Spectrins its structure,function and role in animal cells
•Download as PPTX, PDF•
1 like•1,571 views
Spectrin is a cytoskeletal protein that forms a structural network just inside the cell membrane. It plays several important roles in animal cells. Spectrin forms pentagonal or hexagonal arrangements that help maintain plasma membrane integrity and cytoskeletal structure. It exists as heterotetramers of alpha and beta subunits and interacts with other proteins like ankyrin. Spectrin stabilizes membrane domains and assists in organizing membrane proteins and complexes. It also contributes to cell morphology, mechanical strength, adhesion, signaling pathways, and plays a role in processes like cell division and DNA repair.
Report
Share
Report
Share
Recommended
Conjugation Microbiology powerpoint presentation
Bacterial conjugation involves the transfer of genetic material between bacteria through direct contact. It was first discovered in 1946 by Lederberg and Tatum in E. coli K12 strains. The process involves a donor bacterium containing an F plasmid transferring it to a recipient bacterium. The F plasmid encodes for sex pili that allow the transfer of genetic material. During conjugation, the recipient bacterium receives part of the donor's DNA and may gain traits like antibiotic resistance.
Prions
- In the 1950s, a disease called kuru was observed among the Fore people of New Guinea that caused trembling, loss of motor control, and ultimately death.
- Kuru and other transmissible spongiform encephalopathies (TSEs) are caused by prion proteins, which are unique infectious proteins that can reproduce on their own and convert normal prion proteins into the abnormal infectious form.
- Prions are extremely resistant to heat and chemicals and can survive in the environment for many years. They infect the central nervous system and cause neurodegeneration through a chain reaction that multiplies copies of the infectious prion protein.
Viral taxonomy
The document discusses different systems for classifying viruses. The main systems are the International Committee on Taxonomy of Viruses (ICTV) system and the Baltimore classification system. The ICTV system is based on phenotypic characteristics and defines virus taxonomy, naming conventions, and species. It aims to develop and maintain a universal virus taxonomy. The Baltimore classification system places viruses into one of seven groups based on their nucleic acid and replication strategy.
Group translocation
This is my first presentation here in this platform.
Hope this will be helpful for students and others to understand.
Mitochondrial biogenesis.pptx
Mitochondrial biogenesis is the process by which cells increase mitochondrial numbers. It was first described by John Holloszy in the 1960s, when it was discovered that physical endurance training induced higher mitochondrial content levels, leading to greater glucose uptake by muscles. Mitochondrial biogenesis is activated by numerous different signals during times of cellular stress or in response to environmental stimuli, such as aerobic exercise.
Transposable Elements or Transposition
Transposable elements, also known as transposons or jumping genes, are sequences of DNA that can change positions within a genome. Barbara McClintock discovered transposons in maize in the 1940s. There are two main mechanisms of transposition - replicative transposition, where the transposon replicates before moving to a new location, and non-replicative transposition, where the transposon cuts and pastes without replicating. Major bacterial transposons include insertion sequences, Tn3, and Tn10, which use different transposition mechanisms. Eukaryotic transposons were first discovered in maize and include the Ac and Ds elements, which alter maize kernel color, as
Transposition
transposable element is called transposons.it"s also known as jupping gene . it involves replicative and non replicative mechanism.
Transformation
The document provides information about bacterial transformation. It describes that transformation is the process by which bacteria take up extracellular DNA from their environment. Frederick Griffith first discovered transformation in 1928 while working with pneumococcus bacteria. His experiments showed that a non-virulent rough form could be transformed into a virulent smooth form by DNA from a heat-killed smooth strain. Later experiments by Avery, Macleod and McCarty demonstrated that DNA is the transforming principle and genetic material of bacteria. The document then discusses various methods of bacterial transformation including chemical and physical methods like electroporation and use of calcium chloride. It also explains the molecular mechanism of transformation involving DNA binding, penetration, synapsis formation and integration into the bacterial chromosome.
Recommended
Conjugation Microbiology powerpoint presentation
Bacterial conjugation involves the transfer of genetic material between bacteria through direct contact. It was first discovered in 1946 by Lederberg and Tatum in E. coli K12 strains. The process involves a donor bacterium containing an F plasmid transferring it to a recipient bacterium. The F plasmid encodes for sex pili that allow the transfer of genetic material. During conjugation, the recipient bacterium receives part of the donor's DNA and may gain traits like antibiotic resistance.
Prions
- In the 1950s, a disease called kuru was observed among the Fore people of New Guinea that caused trembling, loss of motor control, and ultimately death.
- Kuru and other transmissible spongiform encephalopathies (TSEs) are caused by prion proteins, which are unique infectious proteins that can reproduce on their own and convert normal prion proteins into the abnormal infectious form.
- Prions are extremely resistant to heat and chemicals and can survive in the environment for many years. They infect the central nervous system and cause neurodegeneration through a chain reaction that multiplies copies of the infectious prion protein.
Viral taxonomy
The document discusses different systems for classifying viruses. The main systems are the International Committee on Taxonomy of Viruses (ICTV) system and the Baltimore classification system. The ICTV system is based on phenotypic characteristics and defines virus taxonomy, naming conventions, and species. It aims to develop and maintain a universal virus taxonomy. The Baltimore classification system places viruses into one of seven groups based on their nucleic acid and replication strategy.
Group translocation
This is my first presentation here in this platform.
Hope this will be helpful for students and others to understand.
Mitochondrial biogenesis.pptx
Mitochondrial biogenesis is the process by which cells increase mitochondrial numbers. It was first described by John Holloszy in the 1960s, when it was discovered that physical endurance training induced higher mitochondrial content levels, leading to greater glucose uptake by muscles. Mitochondrial biogenesis is activated by numerous different signals during times of cellular stress or in response to environmental stimuli, such as aerobic exercise.
Transposable Elements or Transposition
Transposable elements, also known as transposons or jumping genes, are sequences of DNA that can change positions within a genome. Barbara McClintock discovered transposons in maize in the 1940s. There are two main mechanisms of transposition - replicative transposition, where the transposon replicates before moving to a new location, and non-replicative transposition, where the transposon cuts and pastes without replicating. Major bacterial transposons include insertion sequences, Tn3, and Tn10, which use different transposition mechanisms. Eukaryotic transposons were first discovered in maize and include the Ac and Ds elements, which alter maize kernel color, as
Transposition
transposable element is called transposons.it"s also known as jupping gene . it involves replicative and non replicative mechanism.
Transformation
The document provides information about bacterial transformation. It describes that transformation is the process by which bacteria take up extracellular DNA from their environment. Frederick Griffith first discovered transformation in 1928 while working with pneumococcus bacteria. His experiments showed that a non-virulent rough form could be transformed into a virulent smooth form by DNA from a heat-killed smooth strain. Later experiments by Avery, Macleod and McCarty demonstrated that DNA is the transforming principle and genetic material of bacteria. The document then discusses various methods of bacterial transformation including chemical and physical methods like electroporation and use of calcium chloride. It also explains the molecular mechanism of transformation involving DNA binding, penetration, synapsis formation and integration into the bacterial chromosome.
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
This document summarizes the discovery and mechanisms of bacterial conjugation. Joshua Lederberg and Edward Tatum discovered conjugation in 1946 while experimenting with E. coli strains. They found that when two auxotrophic strains were mixed on minimal media, prototrophs grew, indicating genetic transfer. Bernard Davis provided evidence for direct cell-to-cell contact in 1950 using a filter to separate strains. Conjugation involves an F plasmid transferring via pili from an F+ donor cell to an F- recipient. This can involve the whole chromosome in Hfr cells. The mechanisms of F+, F-, and Hfr conjugation and their genetic crosses are then described.
Genetic material
The document discusses the evidence that led scientists to determine that DNA is the genetic material of living organisms. It describes key experiments including Griffith's experiment with pneumonia bacteria strains that showed cell debris could transform one strain into another, and Hershey and Chase's experiment using bacteriophage that demonstrated viral DNA, not proteins, enters host cells to direct new virus production. The document also reviews various lines of evidence that supported DNA as the carrier of hereditary information, such as its location in cell nuclei and ability to accurately replicate.
DNA Supercoiling
This contains DNA Supercoiling , relation between Linking no,Twist and Writhe and a brief explanation of Topoisomerase
Bacterial gene mapping
This document discusses bacterial gene mapping techniques. It describes how interrupted conjugation can be used to map genes by determining the order and time at which donor alleles enter recipient bacterial cells. Recombination between donor and recipient DNA during conjugation allows for mapping analysis. Higher resolution mapping can be done by measuring recombinant frequencies between specific genes to determine smaller map distances. Interrupted conjugation experiments provide an initial rough map that is refined through additional experiments measuring recombinant frequencies between different gene combinations.
Second genetic code overlapping and split genes
1) Eukaryotic genes can be organized in complex ways, including overlapping genes where coding sequences partially overlap, and split genes where coding sequences are interrupted by non-coding intron sequences.
2) Overlapping genes were discovered in bacteriophage X174, where the coding sequences of genes D and E overlap but are translated in different reading frames.
3) Split genes have exons, which are the coding sequences included in mRNA, and introns, which are intervening non-coding sequences not included in mRNA. Split genes were first observed in animal viruses in 1977.
Protein sorting and targeting
protein sorting and targeting ,
protein generation and their distribution to various organelles and out of the cell.
Rolling Circle Replication ppt
Definition - Rolling circle replication is a process of unidirectional nucleic acid replication.
* can rapidly synthesize multiple copies of circular molecules of DNA or RNA, such as plasmids.
* Eucaryotic also replicate.
* widely used in molecular biology & biomedical
nanotechnology, especially in the field of
biosensing (as a method of signal Amplification).
Steps:
Circular ds DNA will be “nicked”
3` end is elongated →Leading strand
5` end displaced → Lagging strand
made up of double stranded by OKAZAKI fragments.
4) Replication of both “ unnicked” and displaced ss DNA
5) Displaced DNA circulates and synthesis its own complementary strand.
Initation-- phosphate ends, by the action of:
a) Helicase
b) Topoisomerases
c) Single stranded binding proteins(SSBPs)
Elongation-OH group of broken strand, using the unbroken strand as a template. The polymerase will start to move in a circle for elongation, due to which it is named as Rolling Circle Model.
end will be displaced and will grow out like a waving thread.
Termination-* At the point of termination, the linear DNA molecule is cleaved from the circle resulting in a double stranded circular DNA molecule and a single- stranded linear DNA molecule.
* The linear single stranded molecule is circularized by the action of ligase and then replication to double stranded circular plasmid molecule.
Example- Conjugation of F+ and F- bacteria
Diagrammatic representation of Rolling circle
some Examples-Viral DNA
* Human herpes virus
* Human papilloma virus
* Geminivirus
Viral RNA
* pospiviridiae
* Avsunviridiae
Reference:- https://en. m. wikipedia.org
what- when- how.com
https//www.sciencedirect.com
www.slideshare.com
Genetics-notes.wikispace.com
you tube
Prescott 5th edition page.no: 236, 237
Brock biology of microorganism , page.no: 253,616
Transduction Feb 2015
Transduction is the transfer of genes between bacteria through bacteriophages. There are two main types: generalized transduction, where any bacterial gene can be transferred via a lytic phage, and specialized transduction, where only certain genes near the phage insertion site are transferred via a temperate phage. Transduction was first discovered in 1952 and shows how phages can pick up bacterial DNA and transfer it to new hosts, altering their genetic characteristics and demonstrating the evolutionary relationship between phages and bacteria.
Dot blotting
Dot blotting involves spotting small amounts of protein samples onto a nitrocellulose or PVDF membrane. The membrane is then blocked and incubated with primary and secondary antibodies. Finally, it is imaged using a chemiluminescent substrate. Dot blotting allows for a quick assay to test antibody binding and determine the appropriate primary antibody concentration for Western blot. It has advantages over Western blot in being faster and less expensive.
homologus recombination
This document summarizes homologous recombination in eukaryotes and bacteria. In eukaryotes, homologous recombination repairs double-strand DNA breaks through either the double-strand break repair (DSBR) pathway or synthesis-dependent strand annealing (SDSA) pathway. The DSBR pathway forms double Holliday junctions that are resolved to result in crossover or non-crossover products. In bacteria, the RecBCD pathway repairs double-strand breaks and the RecF pathway repairs single-strand gaps. Both pathways involve strand invasion and branch migration to facilitate homologous recombination.
Enumeration of viruses
This document discusses methods for enumerating viruses, including direct and indirect methods. Direct enumeration methods like direct electron microscopic count can directly count virus particles but have difficulties. The latex bead method helps minimize issues by adding beads of known concentration. Indirect methods rely on infectivity, including plaque assays where each plaque indicates one infective virus particle, and pock assays used for viruses like pox that form visible lesions. Both indirect methods involve serial dilutions and counting visible plaques or pocks to calculate virus concentration in the original sample.
Reproduction of bacteriophages
Reproduction of bacteriophagesVishwasrao Naik Arts, Commerce And Baba Naik Science Mahavidyalaya, Shirala
1) Bacteriophages reproduce by inserting their nucleic acid into host bacteria and using the host's machinery to produce new virus particles.
2) A one-step growth experiment involves infecting host bacteria with phages and measuring the number of new infectious particles over time. This reveals three phases: a latent period during which no new particles are produced, a burst period where particle numbers rise rapidly as infected cells lyse, and a plateau period where no new infections occur.
3) For example, the T2 bacteriophage has a latent period of around 22 minutes, a burst period of 10 minutes where it produces over 100 new particles per infected cell, and a plateau period of 30 minutes.Synthesis and targeting of mitochondrial proteins
Mitochondrial proteins are essential for processes like oxidative phosphorylation and ATP synthesis. They are synthesized on cytosolic ribosomes and targeted to mitochondria. The precursor proteins contain an N-terminal targeting sequence that binds receptor proteins on the mitochondrial surface. The precursor proteins then pass through membrane channels into the mitochondrial matrix, where the targeting sequence is cleaved off and the proteins fold with the help of chaperones. This import process is tightly regulated and requires coordination between the nuclear and mitochondrial genomes.
Ionophores
the ionophores are the a part of membrane transport system. these slides include general concept of ionophores. useful for the paramedical, medical students.
repetitive and non repetitive dna.pptx
1. Eukaryotic DNA contains repetitive and non-repetitive segments. Repetitive DNA makes up around 50% of the human genome and consists of sequences that are present in copies numbering over a million.
2. Repetitive DNA is divided into highly, moderately, and uniquely repetitive sequences based on copy number. Highly repetitive sequences are present in over 100,000 copies and include satellite and centromeric DNA. Moderately repetitive sequences have between 100-10,000 copies, like ribosomal RNA genes.
3. Non-repetitive or unique sequences make up around 50% of the human genome and contain protein-coding genes and other sequences required for gene expression that generally exist in only
Bacterial transposable elements
Transposable elements are DNA sequences that can change their position within a genome. They are common in bacteria and include insertion sequences (IS elements) and larger transposons. IS elements are short sequences that can insert into bacterial chromosomes, while transposons are composed of IS elements flanking additional genes. Transposition occurs via either replicative or conservative mechanisms, with replicative resulting in duplication of the transposable element. Transposition can cause mutations but also increases genome flexibility and is useful for genetic engineering applications like insertional mutagenesis.
Mitochondrial and bacterial electron transport, oxidation reduction by Akshay...
The document summarizes mitochondrial and bacterial electron transport. It describes the key components of the electron transport chain (ETC) in mitochondria, including four complexes and coenzyme Q that transfer electrons and pump protons. Bacterial ETCs can resemble mitochondria but vary in electron carriers and branches. They are usually shorter and less efficient than mitochondrial ETC. The ETC couples electron transfer with proton pumping to build a proton gradient and facilitate ATP synthesis through oxidative phosphorylation.
Bacteriophage and replication
The document summarizes information about bacteriophages T4 and lambda. It discusses that bacteriophages are viruses that infect bacteria and both T4 and lambda contain dsDNA. T4 is large at 90nm by 200nm with an icosahedral head and long helical tail. Lambda is smaller at 55nm with a non-contractile tail. Both phages can undergo lytic or lysogenic cycles. The lysogenic cycle involves the viral DNA integrating into the host chromosome as a prophage.
DNA TOPOLOGY
DNA topology studies the geometric properties and spatial relationships of DNA that are unaffected by changes in shape or size. It includes phenomena like supercoiling, knots, and catenanes that involve the linking and twisting of the two DNA strands. DNA topology is characterized by parameters like the linking number, which represents the number of times the two strands are twisted around each other. Enzymes called topoisomerases regulate DNA topology by introducing temporary breaks in the DNA strands to allow strand passage and control supercoiling levels.
Complementation test
This document presents information on complementation tests. It defines complementation tests as a method used to determine if two mutations are in the same gene or different genes. It explains that if the mutations are complementary (in different genes), the offspring will show the parental phenotypes, but if they are not complementary (in the same gene), the offspring will show a new phenotype. Three examples of using complementation test results to determine the number of genes involved are provided. The document concludes by citing a reference for more information on assigning mutations to genes using complementation tests.
1. Introduction To Cells
The document defines key cell biology terms and concepts, including:
- Cells are the basic unit of all living things. Animal cells contain structures like the nucleus, cytoplasm, and cell membrane.
- Plant cells also contain a cell wall and chloroplasts. Microscopes are used to observe cell structures.
- Diffusion and osmosis allow movement of substances in and out of cells through selectively permeable membranes down concentration gradients.
Plant and animal cells slideshow
This document discusses and compares the organelles found in plant and animal cells. It describes the cell membrane, cell wall, cytoplasm, nucleus, chloroplasts, vacuoles, mitochondria, endoplasmic reticulum, ribosomes, lysosomes, and Golgi complex. The cell membrane shapes the cell and regulates what enters and exits, while the cell wall provides structure and protection only in plant cells. Chloroplasts perform photosynthesis in plant cells. Vacuoles provide structure, storage, and waste disposal and are larger in plant cells. Other organelles like the nucleus, mitochondria, ER, ribosomes, lysosomes, and Golgi complex have similar functions in both plant and animal cells, such as generating energy
More Related Content
What's hot
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
This document summarizes the discovery and mechanisms of bacterial conjugation. Joshua Lederberg and Edward Tatum discovered conjugation in 1946 while experimenting with E. coli strains. They found that when two auxotrophic strains were mixed on minimal media, prototrophs grew, indicating genetic transfer. Bernard Davis provided evidence for direct cell-to-cell contact in 1950 using a filter to separate strains. Conjugation involves an F plasmid transferring via pili from an F+ donor cell to an F- recipient. This can involve the whole chromosome in Hfr cells. The mechanisms of F+, F-, and Hfr conjugation and their genetic crosses are then described.
Genetic material
The document discusses the evidence that led scientists to determine that DNA is the genetic material of living organisms. It describes key experiments including Griffith's experiment with pneumonia bacteria strains that showed cell debris could transform one strain into another, and Hershey and Chase's experiment using bacteriophage that demonstrated viral DNA, not proteins, enters host cells to direct new virus production. The document also reviews various lines of evidence that supported DNA as the carrier of hereditary information, such as its location in cell nuclei and ability to accurately replicate.
DNA Supercoiling
This contains DNA Supercoiling , relation between Linking no,Twist and Writhe and a brief explanation of Topoisomerase
Bacterial gene mapping
This document discusses bacterial gene mapping techniques. It describes how interrupted conjugation can be used to map genes by determining the order and time at which donor alleles enter recipient bacterial cells. Recombination between donor and recipient DNA during conjugation allows for mapping analysis. Higher resolution mapping can be done by measuring recombinant frequencies between specific genes to determine smaller map distances. Interrupted conjugation experiments provide an initial rough map that is refined through additional experiments measuring recombinant frequencies between different gene combinations.
Second genetic code overlapping and split genes
1) Eukaryotic genes can be organized in complex ways, including overlapping genes where coding sequences partially overlap, and split genes where coding sequences are interrupted by non-coding intron sequences.
2) Overlapping genes were discovered in bacteriophage X174, where the coding sequences of genes D and E overlap but are translated in different reading frames.
3) Split genes have exons, which are the coding sequences included in mRNA, and introns, which are intervening non-coding sequences not included in mRNA. Split genes were first observed in animal viruses in 1977.
Protein sorting and targeting
protein sorting and targeting ,
protein generation and their distribution to various organelles and out of the cell.
Rolling Circle Replication ppt
Definition - Rolling circle replication is a process of unidirectional nucleic acid replication.
* can rapidly synthesize multiple copies of circular molecules of DNA or RNA, such as plasmids.
* Eucaryotic also replicate.
* widely used in molecular biology & biomedical
nanotechnology, especially in the field of
biosensing (as a method of signal Amplification).
Steps:
Circular ds DNA will be “nicked”
3` end is elongated →Leading strand
5` end displaced → Lagging strand
made up of double stranded by OKAZAKI fragments.
4) Replication of both “ unnicked” and displaced ss DNA
5) Displaced DNA circulates and synthesis its own complementary strand.
Initation-- phosphate ends, by the action of:
a) Helicase
b) Topoisomerases
c) Single stranded binding proteins(SSBPs)
Elongation-OH group of broken strand, using the unbroken strand as a template. The polymerase will start to move in a circle for elongation, due to which it is named as Rolling Circle Model.
end will be displaced and will grow out like a waving thread.
Termination-* At the point of termination, the linear DNA molecule is cleaved from the circle resulting in a double stranded circular DNA molecule and a single- stranded linear DNA molecule.
* The linear single stranded molecule is circularized by the action of ligase and then replication to double stranded circular plasmid molecule.
Example- Conjugation of F+ and F- bacteria
Diagrammatic representation of Rolling circle
some Examples-Viral DNA
* Human herpes virus
* Human papilloma virus
* Geminivirus
Viral RNA
* pospiviridiae
* Avsunviridiae
Reference:- https://en. m. wikipedia.org
what- when- how.com
https//www.sciencedirect.com
www.slideshare.com
Genetics-notes.wikispace.com
you tube
Prescott 5th edition page.no: 236, 237
Brock biology of microorganism , page.no: 253,616
Transduction Feb 2015
Transduction is the transfer of genes between bacteria through bacteriophages. There are two main types: generalized transduction, where any bacterial gene can be transferred via a lytic phage, and specialized transduction, where only certain genes near the phage insertion site are transferred via a temperate phage. Transduction was first discovered in 1952 and shows how phages can pick up bacterial DNA and transfer it to new hosts, altering their genetic characteristics and demonstrating the evolutionary relationship between phages and bacteria.
Dot blotting
Dot blotting involves spotting small amounts of protein samples onto a nitrocellulose or PVDF membrane. The membrane is then blocked and incubated with primary and secondary antibodies. Finally, it is imaged using a chemiluminescent substrate. Dot blotting allows for a quick assay to test antibody binding and determine the appropriate primary antibody concentration for Western blot. It has advantages over Western blot in being faster and less expensive.
homologus recombination
This document summarizes homologous recombination in eukaryotes and bacteria. In eukaryotes, homologous recombination repairs double-strand DNA breaks through either the double-strand break repair (DSBR) pathway or synthesis-dependent strand annealing (SDSA) pathway. The DSBR pathway forms double Holliday junctions that are resolved to result in crossover or non-crossover products. In bacteria, the RecBCD pathway repairs double-strand breaks and the RecF pathway repairs single-strand gaps. Both pathways involve strand invasion and branch migration to facilitate homologous recombination.
Enumeration of viruses
This document discusses methods for enumerating viruses, including direct and indirect methods. Direct enumeration methods like direct electron microscopic count can directly count virus particles but have difficulties. The latex bead method helps minimize issues by adding beads of known concentration. Indirect methods rely on infectivity, including plaque assays where each plaque indicates one infective virus particle, and pock assays used for viruses like pox that form visible lesions. Both indirect methods involve serial dilutions and counting visible plaques or pocks to calculate virus concentration in the original sample.
Reproduction of bacteriophages
Reproduction of bacteriophagesVishwasrao Naik Arts, Commerce And Baba Naik Science Mahavidyalaya, Shirala
1) Bacteriophages reproduce by inserting their nucleic acid into host bacteria and using the host's machinery to produce new virus particles.
2) A one-step growth experiment involves infecting host bacteria with phages and measuring the number of new infectious particles over time. This reveals three phases: a latent period during which no new particles are produced, a burst period where particle numbers rise rapidly as infected cells lyse, and a plateau period where no new infections occur.
3) For example, the T2 bacteriophage has a latent period of around 22 minutes, a burst period of 10 minutes where it produces over 100 new particles per infected cell, and a plateau period of 30 minutes.Synthesis and targeting of mitochondrial proteins
Mitochondrial proteins are essential for processes like oxidative phosphorylation and ATP synthesis. They are synthesized on cytosolic ribosomes and targeted to mitochondria. The precursor proteins contain an N-terminal targeting sequence that binds receptor proteins on the mitochondrial surface. The precursor proteins then pass through membrane channels into the mitochondrial matrix, where the targeting sequence is cleaved off and the proteins fold with the help of chaperones. This import process is tightly regulated and requires coordination between the nuclear and mitochondrial genomes.
Ionophores
the ionophores are the a part of membrane transport system. these slides include general concept of ionophores. useful for the paramedical, medical students.
repetitive and non repetitive dna.pptx
1. Eukaryotic DNA contains repetitive and non-repetitive segments. Repetitive DNA makes up around 50% of the human genome and consists of sequences that are present in copies numbering over a million.
2. Repetitive DNA is divided into highly, moderately, and uniquely repetitive sequences based on copy number. Highly repetitive sequences are present in over 100,000 copies and include satellite and centromeric DNA. Moderately repetitive sequences have between 100-10,000 copies, like ribosomal RNA genes.
3. Non-repetitive or unique sequences make up around 50% of the human genome and contain protein-coding genes and other sequences required for gene expression that generally exist in only
Bacterial transposable elements
Transposable elements are DNA sequences that can change their position within a genome. They are common in bacteria and include insertion sequences (IS elements) and larger transposons. IS elements are short sequences that can insert into bacterial chromosomes, while transposons are composed of IS elements flanking additional genes. Transposition occurs via either replicative or conservative mechanisms, with replicative resulting in duplication of the transposable element. Transposition can cause mutations but also increases genome flexibility and is useful for genetic engineering applications like insertional mutagenesis.
Mitochondrial and bacterial electron transport, oxidation reduction by Akshay...
The document summarizes mitochondrial and bacterial electron transport. It describes the key components of the electron transport chain (ETC) in mitochondria, including four complexes and coenzyme Q that transfer electrons and pump protons. Bacterial ETCs can resemble mitochondria but vary in electron carriers and branches. They are usually shorter and less efficient than mitochondrial ETC. The ETC couples electron transfer with proton pumping to build a proton gradient and facilitate ATP synthesis through oxidative phosphorylation.
Bacteriophage and replication
The document summarizes information about bacteriophages T4 and lambda. It discusses that bacteriophages are viruses that infect bacteria and both T4 and lambda contain dsDNA. T4 is large at 90nm by 200nm with an icosahedral head and long helical tail. Lambda is smaller at 55nm with a non-contractile tail. Both phages can undergo lytic or lysogenic cycles. The lysogenic cycle involves the viral DNA integrating into the host chromosome as a prophage.
DNA TOPOLOGY
DNA topology studies the geometric properties and spatial relationships of DNA that are unaffected by changes in shape or size. It includes phenomena like supercoiling, knots, and catenanes that involve the linking and twisting of the two DNA strands. DNA topology is characterized by parameters like the linking number, which represents the number of times the two strands are twisted around each other. Enzymes called topoisomerases regulate DNA topology by introducing temporary breaks in the DNA strands to allow strand passage and control supercoiling levels.
Complementation test
This document presents information on complementation tests. It defines complementation tests as a method used to determine if two mutations are in the same gene or different genes. It explains that if the mutations are complementary (in different genes), the offspring will show the parental phenotypes, but if they are not complementary (in the same gene), the offspring will show a new phenotype. Three examples of using complementation test results to determine the number of genes involved are provided. The document concludes by citing a reference for more information on assigning mutations to genes using complementation tests.
What's hot (20)
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
Conjugation: Discovery, F+, F- and Hfr conjugation, F- genetic crosses
Mitochondrial and bacterial electron transport, oxidation reduction by Akshay...
Mitochondrial and bacterial electron transport, oxidation reduction by Akshay...
Viewers also liked
1. Introduction To Cells
The document defines key cell biology terms and concepts, including:
- Cells are the basic unit of all living things. Animal cells contain structures like the nucleus, cytoplasm, and cell membrane.
- Plant cells also contain a cell wall and chloroplasts. Microscopes are used to observe cell structures.
- Diffusion and osmosis allow movement of substances in and out of cells through selectively permeable membranes down concentration gradients.
Plant and animal cells slideshow
This document discusses and compares the organelles found in plant and animal cells. It describes the cell membrane, cell wall, cytoplasm, nucleus, chloroplasts, vacuoles, mitochondria, endoplasmic reticulum, ribosomes, lysosomes, and Golgi complex. The cell membrane shapes the cell and regulates what enters and exits, while the cell wall provides structure and protection only in plant cells. Chloroplasts perform photosynthesis in plant cells. Vacuoles provide structure, storage, and waste disposal and are larger in plant cells. Other organelles like the nucleus, mitochondria, ER, ribosomes, lysosomes, and Golgi complex have similar functions in both plant and animal cells, such as generating energy
Ppt defence thesis 3
DMT-1 is a transporter protein that facilitates the transport of divalent metal ions like iron, manganese, zinc, and cadmium across biological membranes. This study examined DMT-1 expression and localization in placentas from women living in cadmium-contaminated and non-contaminated areas of Thailand. Placental and blood cadmium levels were higher in the contaminated area group. DMT-1 protein was localized to the syncytiotrophoblast layer and fetal blood vessels of the placenta. DMT-1 mRNA and protein levels in placentas were positively associated with maternal blood and placental cadmium levels. This suggests cadmium exposure increases
Animal cell structure_and_function_(teacher)
This document provides a quiz to test knowledge of organelles in animal cells. It begins with an overview of the organelles and their numbers on a diagram of a cell. The multiple choice quiz then tests identification of 15 organelles based on images and states their functions. On completion, it congratulates the user and reviews the key things one should know about animal cell structure and function.
Specialized cells presentation
Specialized cells have specific jobs in multicellular organisms and differ from typical cells. Examples include skin, blood, nerve, liver and muscle cells which perform distinct functions. Specialized cell types allow complex organisms to carry out different processes through cellular specialization rather than relying on one cell type alone.
4. Adaptations
This document covers plant and animal adaptations for maintaining water balance. It discusses how plants transport water and regulate transpiration through structures like stomata. It also examines the challenges of osmoregulation for freshwater and saltwater fish, and the adaptations of salmon, eels, and desert mammals to balance water in their environments. Adaptations include physiological processes, structural features, and behavioral responses that help organisms survive where they live.
Animal cells and plant cells
The document summarizes the key parts and functions of animal and plant cells. For animal cells, the main parts are the cell membrane, cytoplasm, and nucleus. The cell membrane controls what enters and exits the cell. The cytoplasm is the jelly-like interior where cell activities occur. The nucleus acts as the control center storing DNA. For plant cells, the main parts are the cell wall, cell membrane, cytoplasm, chloroplasts, and nucleus. The cell wall provides structure, while chloroplasts facilitate photosynthesis to produce food. Both cell types share a nucleus that controls the cell and cytoplasm for internal processes.
Cell structure and organisation
This document discusses cell structure and organization. It defines key terms like organelle, cell membrane, nucleus, cytoplasm and compares typical plant and animal cells. It explains how cell structure relates to function in cells like root hair cells, xylem vessels and red blood cells. Finally, it describes how cells work together to form tissues, organs and organ systems within multicellular organisms.
Specialized Cells, Biology
Specialized cells in plants and animals have unique structures and functions. The document discusses several types of specialized cells including red blood cells, white blood cells, nerve cells, muscle cells, sperm cells, egg cells, root hair cells, palisade cells, and xylem cells. Red blood cells carry oxygen throughout the body while white blood cells protect the body by killing bacteria. Nerve cells carry electrical signals and coordinate functions. Muscle cells allow movement by contracting. Sperm and egg cells are reproductive cells that combine during fertilization. Root hair cells absorb water and minerals in plant roots. Palisade cells contain chloroplasts to perform photosynthesis. Xylem cells transport water and provide structure in plant stems.
Viewers also liked (9)
Similar to Spectrins its structure,function and role in animal cells
Role of Tyrosine Kinase in cancer
This presentation gives the basic idea, about the information on the role of tyrosine kinases in cancer. I have also included a phylogenetic tree for finding the relatedness between different organisms.
NGUYENTHINHI-W9.pptx
1. The document reports on a study investigating the role of insulin signaling in pancreatic β cells using Cre-loxP mediated recombination to generate βIRKO mice lacking the insulin receptor in β cells.
2. Results showed βIRKO mice exhibited impaired glucose tolerance and insulin secretion compared to controls. Expression of genes CENP-A and PLK1 were decreased in βIRKO cells.
3. Further experiments demonstrated insulin stimulates FoxM1 binding to the CENP-A and PLK1 genes, and CENP-A expression is reduced in type 2 diabetes patient islets. Knockout of CENP-A in β cells decreased proliferation.
Dystrophin-glycoprotein-complex PPT.pptx
This document discusses the dystrophin glycoprotein complex (DGC) and staining of muscle tissue. It begins with an introduction to muscle contraction and the role of the DGC in providing a mechanical link from the cytoskeleton to the extracellular matrix. It then describes the various proteins that make up the DGC, including dystrophin, dystroglycan, sarcoglycans, dystrobrevins, syntrophins, sarcospan, caveolin-3, and nitric oxide synthase. It details the structure and functions of these proteins. Finally, it discusses techniques for staining muscle tissue, including hematoxylin and eosin staining and NADH staining, which can identify different muscle fiber types.
Molecular chaperones
This document provides an overview of molecular chaperones. It defines chaperones as proteins that assist in protein folding but are not part of the final structure. Chaperones exist in all cellular compartments and help prevent protein misfolding and aggregation. They are classified as intra-molecular or inter-molecular. The best characterized system is the GroEL/GroES complex which uses ATP to encapsulate proteins and facilitate folding. Chaperones have implications for developing treatments for diseases like cancers and lysosomal storage disorders.
Novel drug target-Enzymes
ROCK (Rho-associated protein kinase) is a kinase enzyme that regulates the shape and movement of cells through effects on the cytoskeleton. It has two isoforms, ROCK1 and ROCK2, that are highly similar. ROCK phosphorylates several substrates that regulate actin filament organization and cellular contractility. Due to its role in many physiological processes, ROCK has implications for diseases like diabetes, neurodegeneration, pulmonary hypertension and cancer. ROCK inhibitors thus have potential as novel therapeutics.
PROTEOMICS IN BLOOD BANKING. DIFFERENT TYPES OF PROTEOMICS
Proteomics is the study of the proteome, which is the complete set of proteins expressed by a genome or cell. It uses technologies like mass spectrometry and genetic analysis to study protein activities, modifications, localization, and interactions. Proteomics can provide diagnostic tools for diseases by identifying disease-associated proteins before clinical symptoms appear. Some applications of proteomics include structural proteomics to predict protein structure and function, functional proteomics to analyze protein networks, and expression proteomics to study quantitative protein expression changes. Key techniques in proteomics include protein separation methods like 1D and 2D gel electrophoresis, peptide mass fingerprinting using mass spectrometry to identify proteins, and databases to analyze mass spectrometry data. Proteomics has
Extracellular Matrix : Session 3
The document summarizes several bone proteins found in the extracellular matrix. It discusses the roles of osteocalcin, osteopontin, osteonectin, BMP, and other proteins in bone formation, mineralization, and regulation of cellular activity. Osteocalcin is involved in mineralization and glucose metabolism. Osteopontin anchors osteoclasts to bone and regulates inflammation. Osteonectin binds tightly to hydroxyapatite and regulates mineralization. BMPs induce bone and cartilage formation through signaling pathways.
Dentin -kunal parekh..advancd oral biology
1. Odontoblasts differentiate from dental papilla cells under the influence of inner dental epithelium and form dentin.
2. Initial odontoblast differentiation requires a fibronectin-rich substratum, aperiodic fibrils, TGF-β1, calcium, and enamel matrix proteins.
3. Mature odontoblasts are polarized cells that synthesize and secrete dentin matrix proteins such as collagen type I, dentin sialophosphoprotein, dentin phosphoprotein, and proteoglycans via the rough endoplasmic reticulum, Golgi complex, and secretory granules.
PI3 kinase pathway
The PI3-Kinase pathway is a complex signaling pathway that regulates many important cellular processes like growth, translation, and apoptosis. Studies in simpler organisms helped illuminate the basic pathway but it is more complex in mammals. At its core, extracellular signals activate PI3K which catalyzes the formation of PIP3 from PIP2 to transmit signals by recruiting proteins to the membrane like AKT. AKT then phosphorylates many substrates to influence processes like cell growth, survival and metabolism. Deregulation of this pathway through mutations in genes like PI3K, PTEN and AKT is strongly implicated in cancer development.
Seminario manuela rios
The document summarizes a study that investigated bone mass and mitochondria in osteogenic cells of ovariectomized mice with genetic deletion of PINK1. The study used techniques like PCR, Western blot, and RT-PCR to analyze proteins and identify specific sequences. The results are presented in figures 2, 3, and 6. The discussion reviews how estrogens and androgens protect osteoblasts from oxidative stress and how PINK1 stimulates mitochondria generation. The conclusion states that suppressing PINK1 activity during osteoblast differentiation is related to mitochondrial quality control and reactive oxygen species production. Continuing this research could help treatments for osteoporosis by understanding PINK1's molecular role in osteoblast differentiation.
Epithelium- Role in defense.ppt
Gingival epithelium acts as an important part of the innate immune response. It expresses toll-like receptors that recognize pathogens and produce chemokines. The epithelium also produces antimicrobial peptides like defensins and has antigen presenting cells that link the innate and adaptive immune responses. This represents a paradigm shift from the gingiva being considered a passive physical barrier to an active player in the host defense against bacterial challenges.
Chaperones
Chaperones are a functionally related group of proteins that assist the covalent folding or unfolding and the assembly or disassembly of other macromolecular structures.
Eicosanoids
Eicosanoids is the class of lipids derived from arachidonic acid. Eicosanoids play an important role in the growth and development, cellular signalling, drug response, platelet action and maintenance of body homeostasis.
Wnt-Signalling in Endocrinology
Wnt signaling pathways play an important role in many endocrine functions and diseases. Wnt signaling regulates pancreatic beta cell proliferation, adipose tissue development, steroidogenesis in the adrenal cortex, bone mineral metabolism, and sex development. Therapies targeting Wnt signaling show promise for diseases like osteoporosis, with anti-sclerostin therapies approved to treat post-menopausal osteoporosis. Future therapies may target TCF7L2 to prevent diabetes or treat adrenal tumors by modulating Wnt signaling.
proteomics scope and its importance by aniqa atta
Title: proteomics scope and its importance
this lect will cover that what is proteomics? why it is important and also this helps us in understanding biological processes and advancing the field of system biology. for identification of proteins in normal and diseadse condition etc. this lecture will help all the students in field of biotechnology, molecular biology and field of proteomics students,
Prostaglandins.docx
Prostaglandins, leukotrienes, angiotensin, bradykinin, and substance P are biologically active lipid mediators that play important roles in inflammation and other physiological processes. Prostaglandins and leukotrienes are derived from arachidonic acid and function as autacoids. Angiotensin is derived from angiotensinogen and regulates blood pressure and sodium balance. Bradykinin is formed from kininogens and causes vasodilation. Substance P functions as a neurotransmitter and mediates pain, inflammation, and vasodilation. These mediators act through G-protein coupled receptors and have diverse effects in various organ systems.
Characterising the Interactome of EZH2 in Embryonic Stem Cells (3)
This study aimed to characterize the interactome of Ezh2, the core catalytic subunit of the PRC2 complex, in embryonic stem cells using mass spectrometry. Ezh2 and PRC2 are important for maintaining pluripotency and regulating stem cell differentiation through epigenetic modifications. The experimental interactome was enriched for chromatin remodeling proteins and transcriptional regulators as expected, as well as splicing factors, which prompted further analysis. Characterizing the interaction between splicing factors and PRC2 could provide insight into how stem cell differentiation is controlled while maintaining stemness, and how aberrations can cause cancer. Mass spectrometry identified potential high-confidence Ezh2 interactors and bioinformatics analysis revealed the complexity of the Ezh2 interactome
cell cell communication
This document discusses cell-to-cell communication through signaling molecules that bind to membrane receptors. It describes three main types of membrane receptors - channel-linked receptors that open or close ion channels, catalytic receptors that activate intracellular signaling pathways, and G-protein-linked receptors that activate second messengers through G proteins. It also discusses the association of the plasma membrane and cytoskeleton through integrin proteins and the role of this connection in determining cell shape.
Lecture_Chromatin remodelling_slideshare.pdf
1. Chromatin remodeling complexes use ATP hydrolysis to modify nucleosome structure and expose DNA for gene expression. The main classes are ATP-independent complexes and ATP-dependent complexes like ISWI and SWI/SNF.
2. Post-translational modifications of histone tails like acetylation, methylation, and phosphorylation can affect chromatin structure and transcription by altering DNA-histone interactions.
3. Chromatin remodeling is important for differential gene expression in specialized cell types and controlling DNA accessibility for transcription.
Similar to Spectrins its structure,function and role in animal cells (20)
PROTEOMICS IN BLOOD BANKING. DIFFERENT TYPES OF PROTEOMICS
PROTEOMICS IN BLOOD BANKING. DIFFERENT TYPES OF PROTEOMICS
Apoptosis : caspases, extrinsic and intrinsic pathways.
Apoptosis : caspases, extrinsic and intrinsic pathways.
Characterising the Interactome of EZH2 in Embryonic Stem Cells (3)
Characterising the Interactome of EZH2 in Embryonic Stem Cells (3)
Recently uploaded
How to Download & Install Module From the Odoo App Store in Odoo 17
Custom modules offer the flexibility to extend Odoo's capabilities, address unique requirements, and optimize workflows to align seamlessly with your organization's processes. By leveraging custom modules, businesses can unlock greater efficiency, productivity, and innovation, empowering them to stay competitive in today's dynamic market landscape. In this tutorial, we'll guide you step by step on how to easily download and install modules from the Odoo App Store.
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 8 - CẢ NĂM - FRIENDS PLUS - NĂM HỌC 2023-2024 (B...
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 8 - CẢ NĂM - FRIENDS PLUS - NĂM HỌC 2023-2024 (B...Nguyen Thanh Tu Collection
https://app.box.com/s/nrwz52lilmrw6m5kqeqn83q6vbdp8yzpGeography as a Discipline Chapter 1 __ Class 11 Geography NCERT _ Class Notes...
Geography as discipline
Accounting for Restricted Grants When and How To Record Properly
In this webinar, member learned how to stay in compliance with generally accepted accounting principles (GAAP) for restricted grants.
CapTechTalks Webinar Slides June 2024 Donovan Wright.pptx
Slides from a Capitol Technology University webinar held June 20, 2024. The webinar featured Dr. Donovan Wright, presenting on the Department of Defense Digital Transformation.
How to Manage Reception Report in Odoo 17
A business may deal with both sales and purchases occasionally. They buy things from vendors and then sell them to their customers. Such dealings can be confusing at times. Because multiple clients may inquire about the same product at the same time, after purchasing those products, customers must be assigned to them. Odoo has a tool called Reception Report that can be used to complete this assignment. By enabling this, a reception report comes automatically after confirming a receipt, from which we can assign products to orders.
Level 3 NCEA - NZ: A Nation In the Making 1872 - 1900 SML.ppt
The History of NZ 1870-1900.
Making of a Nation.
From the NZ Wars to Liberals,
Richard Seddon, George Grey,
Social Laboratory, New Zealand,
Confiscations, Kotahitanga, Kingitanga, Parliament, Suffrage, Repudiation, Economic Change, Agriculture, Gold Mining, Timber, Flax, Sheep, Dairying,
220711130100 udita Chakraborty Aims and objectives of national policy on inf...
Aims and objectives of national policy on information and communication technology(ICT) in school education in india
欧洲杯下注-欧洲杯下注押注官网-欧洲杯下注押注网站|【网址🎉ac44.net🎉】
【网址🎉ac44.net🎉】欧洲杯下注在体育博彩方面，不难发现，欧洲杯下注多为英式运动提供投注。欧洲杯下注为丰富多彩的体育项目提供投注，如足球、赛马、板球和飞镖，但这不是欧洲杯下注的唯一优势。在欧洲杯下注，全世界玩家都可以找到自己感兴趣的比赛进行投注。欧洲杯下注为网球和美式运动如棒球、美式足球、篮球、冰球开出的投注同样值得关注。在夏季或冬季奥运会方面，欧洲杯下注为玩家开出了丰富多彩的服务，是你的不二之选。你还可以投注水球、自行车和班迪球等小众体育项目，甚至可以为武术、拳击和综合格斗投注。欧洲杯下注为众多体育项目开出滚球投注。
THE SACRIFICE HOW PRO-PALESTINE PROTESTS STUDENTS ARE SACRIFICING TO CHANGE T...
The recent surge in pro-Palestine student activism has prompted significant responses from universities, ranging from negotiations and divestment commitments to increased transparency about investments in companies supporting the war on Gaza. This activism has led to the cessation of student encampments but also highlighted the substantial sacrifices made by students, including academic disruptions and personal risks. The primary drivers of these protests are poor university administration, lack of transparency, and inadequate communication between officials and students. This study examines the profound emotional, psychological, and professional impacts on students engaged in pro-Palestine protests, focusing on Generation Z's (Gen-Z) activism dynamics. This paper explores the significant sacrifices made by these students and even the professors supporting the pro-Palestine movement, with a focus on recent global movements. Through an in-depth analysis of printed and electronic media, the study examines the impacts of these sacrifices on the academic and personal lives of those involved. The paper highlights examples from various universities, demonstrating student activism's long-term and short-term effects, including disciplinary actions, social backlash, and career implications. The researchers also explore the broader implications of student sacrifices. The findings reveal that these sacrifices are driven by a profound commitment to justice and human rights, and are influenced by the increasing availability of information, peer interactions, and personal convictions. The study also discusses the broader implications of this activism, comparing it to historical precedents and assessing its potential to influence policy and public opinion. The emotional and psychological toll on student activists is significant, but their sense of purpose and community support mitigates some of these challenges. However, the researchers call for acknowledging the broader Impact of these sacrifices on the future global movement of FreePalestine.
How to Setup Default Value for a Field in Odoo 17
In Odoo, we can set a default value for a field during the creation of a record for a model. We have many methods in odoo for setting a default value to the field.
220711130083 SUBHASHREE RAKSHIT Internet resources for social science
Internet resources for social science
INTRODUCTION TO HOSPITALS & AND ITS ORGANIZATION
The document discuss about the hospitals and it's organization .
Recently uploaded (20)
How to Download & Install Module From the Odoo App Store in Odoo 17
How to Download & Install Module From the Odoo App Store in Odoo 17
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 8 - CẢ NĂM - FRIENDS PLUS - NĂM HỌC 2023-2024 (B...
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 8 - CẢ NĂM - FRIENDS PLUS - NĂM HỌC 2023-2024 (B...
Geography as a Discipline Chapter 1 __ Class 11 Geography NCERT _ Class Notes...
Geography as a Discipline Chapter 1 __ Class 11 Geography NCERT _ Class Notes...
Accounting for Restricted Grants When and How To Record Properly
Accounting for Restricted Grants When and How To Record Properly
CapTechTalks Webinar Slides June 2024 Donovan Wright.pptx
CapTechTalks Webinar Slides June 2024 Donovan Wright.pptx
SWOT analysis in the project Keeping the Memory @live.pptx
SWOT analysis in the project Keeping the Memory @live.pptx
220711130088 Sumi Basak Virtual University EPC 3.pptx
220711130088 Sumi Basak Virtual University EPC 3.pptx
Level 3 NCEA - NZ: A Nation In the Making 1872 - 1900 SML.ppt
Level 3 NCEA - NZ: A Nation In the Making 1872 - 1900 SML.ppt
220711130100 udita Chakraborty Aims and objectives of national policy on inf...
220711130100 udita Chakraborty Aims and objectives of national policy on inf...
THE SACRIFICE HOW PRO-PALESTINE PROTESTS STUDENTS ARE SACRIFICING TO CHANGE T...
THE SACRIFICE HOW PRO-PALESTINE PROTESTS STUDENTS ARE SACRIFICING TO CHANGE T...
220711130083 SUBHASHREE RAKSHIT Internet resources for social science
220711130083 SUBHASHREE RAKSHIT Internet resources for social science
Spectrins its structure,function and role in animal cells
- 1. Spectrins its structure,function and role in animal cells
- 2. INTRODUcTION • Spectrin is a cytoskeletal protein. • First isolated as a major protein component of human red blood cells. • Forms pentagonal or hexagonal arrangements, playing an important role in maintenance of plasma membrane integrity and cytoskeletal structure.
- 3. Spectrins: several genes and numerous isoforms widely distributed in all metazoan cells • Exist mainly as heterotetramers made of various a and b subunit isoforms. • SPTA1 and SPTAN,SPTB,SPTBN1, SPTBN2, SPTBN4 & SPTBN5 • C.elegans and D.melanogaster-a- spectrin bG & bH-spectrin. • a-Spectrins contain 20 spectrin repeats, b-spectrins are made of 17 spectrin repeats (b1-b17), while the heavy bV-spectrins contain 30 repeats. • Ankyrin, 4.1 complex-which includes actin, dematin,adducin, tropomyosin and tropomodulin, glycophorin C.
- 4. Spectrins are a structural platform for stabilization and activation of membrane microdomains • Spectrin-based skeleton participates in the organization of specialized membranes. • No accumulation of membrane partners at the appropriate site within the membrane. • Spinocerebellar ataxia type 5 (SCA5) and neurodegenerative disease. • Tremors and contraction of the hindlimbs-mice. • Loss of Na+K+ ATPase from the basolateral domain of epithelial cells- Drosophila.
- 5. Spectrins are multifunctional proteins involved in regulation of cell morphology and mechanical properties • Hereditary hemolytic anemia associated with mutations in both aI- and bI-spectrins. • In epithelial cells, knockdown of bII-spectrin results in loss of the lateral membrane, expansion of the apical and basal membrane area, and conversion of cells from columnar to squamous morphology. • a- and b-spectrins are required during nervous system development-NCAM.
- 6. Spectrins, cell cycle and DNA repair • The presence of spectrin in a complex including TGFb-R1- Beckwith-Wiedemann syndrome (BWS). • Spectrin depleted melanoma cells cell cycle arrest in the G1 phase. • aII-spectrin binds to DNA at the sites of damage and acts as a scaffold, recruiting of repair proteins. • Decreased cell growth and survival.
- 7. Spectrin contributes with actin to cell adhesion and spreading • Spectrin depleted cells exhibited modifications of the actin cytoskeleton,such as loss of stress fibers, alterations of focal contacts and modified expression of some integrins.
- 8. Control of activation of transmembrane proteins • Spectrin-based skeleton via its two major proteins, spectrin and ankyrin, directly binds CD45 in lymphocytes. • Spectrin aggregates contain several proteins, such as hsp70, receptor for activated C kinase-1 (RAC-1) and PKCh. • Participation of spectrin in signaling function in lymphocytes. • PKCh relationship to spectrin and its participation in regulating early steps of apoptosis.
- 9. Spectrin functions can be regulated by posttranslational modifications Spectrin posttranslational regulation- apoptosis/necrosis,secretion/ endocytosis, vertebrate lens development,pathologies in the central nervous system. • b-Spectrin phosphorylation essential in destabilization of the erythrocyte membrane skeleton. • Proteolysis of spectrin .
- 10. Spectrin Plays a Critical Role in Platelet Formation • Diane Krause, MD, PhD http://www.hematology.org/P ublications/Hematologist/201 1/6988.aspx September 1, 2011 • Using a novel spectrin tetramer-disrupting protein • During megakaryocyte maturation, an extensive invaginated membrane system forms. Without intact spectrin tetramers, megakaryocytes lacked this extensive membrane structure.
- 11. Shigella flexneri utilize the spectrin cytoskeleton during invasion and comet tail generation • http://www.ncbi.nlm.nih.gov/pub med/22424399 • Tyson J Ruetz1, Ann E Lin1 and Julian A Guttman* 2012 Mar 16 • Following internalization, all three proteins are recruited to the internalized bacteria, spectrin recruitment to those structures in the absence of adducin or p4.1. • Invasion of intestinal epithelial cells and comet tail-based motility in host cells are key for S. flexneri to access replicative niches and disseminate throughout host tissues [2].
- 12. BIBLIOGRAPHY • www.ncbi.nlm.nih.gov/pubmed/22424399 • www.hematology.org/Publications/Hematologist/2011/6988. • Spectrin-based skeleton as an actor in cell signaling B. Machnicka • R. Grochowalska • D. M. Bogusławska •A. F. Sikorski • M. C. Lecomte Published: 30 August 2011 Springerlink.com • en.wikipedia.org/wiki/Spectrin