The document summarizes key components of the extracellular matrix (ECM). It describes three main classes of ECM molecules: structural proteins like collagen and elastin that provide structure, proteoglycans that embed the structural proteins, and adhesive glycoproteins like fibronectin and laminin that attach cells to the matrix. It provides details on the composition, structure and function of proteoglycans, collagen, elastic fibers, reticular fibers and adhesive glycoproteins. It also discusses how defects in ECM synthesis can lead to diseases and conditions like muscular dystrophy.
The document discusses several proteins including hemoglobin, myoglobin, immunoglobins, actin, and myosin. It provides details on their structure, function, and mechanisms. Hemoglobin transports oxygen in red blood cells. Myoglobin stores oxygen in muscle cells. Immunoglobins recognize and bind pathogens to trigger an immune response. Actin and myosin interact through a sliding filament mechanism to generate muscle contraction powered by ATP hydrolysis.
The document summarizes key components of the extracellular matrix (ECM). It describes three main classes of ECM molecules: structural proteins like collagen and elastin that provide structure, proteoglycans that embed the structural proteins, and adhesive glycoproteins like fibronectin and laminin that attach cells to the matrix. It provides details on the composition, structure and function of proteoglycans, collagen, elastic fibers, reticular fibers and adhesive glycoproteins. It also discusses how defects in ECM synthesis can lead to diseases and conditions like muscular dystrophy.
The document discusses several proteins including hemoglobin, myoglobin, immunoglobins, actin, and myosin. It provides details on their structure, function, and mechanisms. Hemoglobin transports oxygen in red blood cells. Myoglobin stores oxygen in muscle cells. Immunoglobins recognize and bind pathogens to trigger an immune response. Actin and myosin interact through a sliding filament mechanism to generate muscle contraction powered by ATP hydrolysis.
A complete presentation on cholesterol metabolism . covering from introduction of cholesterol to history and complete process of cholesterol synthesis or metabolism. also includes disease related to cholesterol metabolism. hypercholesterolemia and hypocholesterolemia
Lecture 2- Fatty acid activation and carnitine shuttle.pptxArpitaGupte1
This document discusses lipid metabolism, specifically the multi-stage process of fatty acid utilization through beta-oxidation. It describes:
1) Fatty acids must be activated by binding to coenzyme A in the cytosol or ER membranes in an ATP-dependent process forming acyl-CoA.
2) Long chain acyl-CoAs cannot diffuse into mitochondria and are transported using carnitine, which transfers the fatty acid between CoA and its own hydroxyl group.
3) Carnitine palmitoyl transferase I and II facilitate the three step process of transferring the fatty acyl group into the mitochondrial matrix, where it is available for beta-oxidation to produce acetyl
Hormones can be classified in several ways based on their chemical composition, mechanism of action, target effects, and whether they stimulate other endocrine glands. The three main types are steroid hormones, peptide hormones, and amine hormones. Steroid hormones are lipophilic and act via nuclear receptors. Peptide hormones are hydrophilic and act through cell surface receptors and secondary messengers like cAMP. Amine hormones have properties of both peptides and steroids. Hormones also differ in their local versus general actions, kinetic versus metabolic effects, and whether they stimulate other glands via tropic hormones or act directly on tissues.
Integration of metabolism for medical schoolRavi Kiran
The document discusses how metabolism is integrated in multicellular organisms. It describes how different organs specialize in certain metabolic functions and work together to maintain energy homeostasis. The liver plays a central role in processing nutrients from the intestines and regulating fuel levels in the bloodstream. During periods of food intake, the pancreas releases insulin which promotes fuel storage, while glucagon released during fasting mobilizes glycogen and fatty acid reserves. Prolonged starvation results in the liver producing ketone bodies from fatty acids as an alternative fuel for tissues like the brain and heart.
Slide Apparato del Golgi, a cura di Catalano Michele e Galli Valerio (Corso di istologia, L.M. in medicina e chirurgia - a.a. 2011-2012)
http://medmedicine.it
Cell cycle regulation presentation by me and my colleagues. Not the Best work but still it will give a general idea about DNA damage checkpoints, roles of Cdk-Cyclin complexes, Rb proteins, ATM&ATR kinases, p51, etc.
Reference : Nature reviews & The Cell a molecular approach. (cooper)
Dr. Mina Bissell gave a presentation on extracellular matrices. She discussed how ECMs are composed of fibrous proteins and glycosaminoglycans that form an interlocking mesh. ECMs perform important functions such as providing structural support and compartmentalizing tissues. They also present signals to cells and serve as highways for cell migration. Basement membranes are a specialized ECM layer that surround epithelia and other cell types. Collagen and laminins are major ECM proteins that form intricate structures and provide strength. Mutations in these proteins can lead to diseases like osteogenesis imperfecta and muscular dystrophies.
Hormones & related bio signaling compounds (Part 1)Eneutron
This document summarizes several hormones and related compounds involved in the endocrine system. It discusses hormones released by the hypothalamus and pituitary gland, including corticotropin-releasing hormone, somatotropin-releasing hormone, somatostatin, thyrotropin-releasing hormone, and gonadotropin-releasing hormone. It also describes hormones produced by the pituitary gland, such as ACTH, MSH, prolactin, growth hormone, TSH, and LH/FSH. Additionally, it covers insulin, glucagon, thyroid hormones, parathyroid hormone, gastrointestinal hormones like gastrin and cholecystokinin, and the structures and functions of
Signal transduction and hormone receptor complexmuti ullah
This document discusses signal transduction and hormone receptor complexes. It describes how signals like antigens, growth factors, hormones, neurotransmitters and nutrients can influence protein location and cell processes. It discusses ligands that bind receptors to activate or prevent signal transduction. There are different classes of receptors including intracellular receptors, cell surface receptors, G-protein coupled receptors, receptor tyrosine kinases, and nuclear receptors. The document also summarizes the structure and function of insulin receptors and other hormone receptors, as well as the specificity, selectivity and steps of signal transduction.
This document discusses tumor suppressor genes. It begins by explaining that cancer is caused by genetic mutations, and describes the characteristic properties of cancer cells that result from these genetic changes. It then discusses two classes of genes affected in cancer - oncogenes and tumor suppressor genes. Oncogenes contribute to tumor development, while tumor suppressors support tumor development when their function is lost. The rest of the document provides details on specific tumor suppressor genes like RB, p53, PTEN, NF1, and BRCA1/2; their functions in inhibiting cell growth and proliferation; and the genetic and epigenetic mechanisms by which their inactivation can lead to cancer development.
Il presente atlante istologico è stato realizzato dagli alunni Maccaferri Ambra e Ghisellini Alberto (5R 2010-11) nell’ambito di una convenzione stipulata tra l’Istituto Bassi Burgatti e l’ Istituto Ramazzini Cooperativa Sociale Onlus - Centro di Ricerca sul Cancro "Cesare Maltoni" di Bentivoglio (BO)
Peptides and proteins structure and functionsRamesh Gupta
Peptides and proteins are polymers of amino acids. Their structure and function depend on the nature, sequence, and spatial arrangement of amino acids. Peptides generally have fewer than 100 amino acids, while proteins have 100 or more. Many peptides are formed by protein breakdown. Examples of physiologically active peptides include glutathione, bradykinin, angiotensin, vasopressin, oxytocin, and TRH. Proteins perform functions like maintaining pH and osmotic balance. They also include enzymes, hormones, and structural components of tissues.
The extracellular matrix (ECM) is a collection of molecules secreted by cells that provides structural and biochemical support to surrounding cells. It is composed of water, proteins, and polysaccharides. The ECM contains collagens, fibronectin, laminins, and proteoglycans. Collagen is the most abundant protein in the ECM and forms fibrils that provide structure. The ECM regulates cell behavior, provides tissue structure and strength, and mediates cell signaling and homeostasis. Genetic defects in ECM proteins can cause diseases like osteogenesis imperfecta or fibrosis.
Cell adhesion molecules are proteins located on cell surfaces that allow cells to adhere to each other and maintain tissue structure. The most important type are cadherins, which are calcium-dependent transmembrane proteins that connect to other cadherins on adjacent cells and link to the actin cytoskeleton. Cadherins help organize cell layers and tissues during development by promoting adhesion between similar cell types and separation between dissimilar ones. Other classes of cell adhesion molecules include integrins, IgCAMs, and selectins, which provide both calcium-dependent and calcium-independent adhesion between cells and the extracellular matrix.
This document summarizes different types of cell adhesion molecules (CAMs). It discusses cadherins, which are the primary CAMs in adherens junctions and desmosomes. Integrins are heterodimeric receptors that connect the intracellular and extracellular environments and are involved in cell adhesion to the extracellular matrix. The immunoglobulin superfamily of CAMs are calcium-independent transmembrane proteins with immunoglobulin-like domains. Selectins mediate the initial tethering of leukocytes to endothelial cells during inflammation. Cell adhesion molecules play important roles in processes like embryogenesis, immunity, tissue development, and cancer metastasis.
The document discusses the composition and function of the extracellular matrix (ECM). It is composed of cells, fibrillar proteins like collagen and elastin, proteoglycans, and structural glycoproteins. The ECM provides structural support and regulates cell behavior. Collagen is the most abundant protein and forms strong fibrils through post-translational modifications and crosslinking. Proteoglycans are heavily glycosylated proteins that contain glycosaminoglycan chains and help organize the ECM.
Intercellular connections and molecular motorsAnwar Siddiqui
This document summarizes a physiology seminar on intercellular connections and molecular motors. It discusses various cell adhesion molecules like cadherins, selectins, immunoglobulin superfamily molecules, and integrins that mediate cell-cell and cell-matrix adhesion. It also describes different types of intercellular junctions such as tight junctions, desmosomes, and hemidesmosomes. Finally, it provides an overview of molecular motors like kinesin, dynein, and myosin that transport cargo within cells and generate forces through ATP hydrolysis.
A complete presentation on cholesterol metabolism . covering from introduction of cholesterol to history and complete process of cholesterol synthesis or metabolism. also includes disease related to cholesterol metabolism. hypercholesterolemia and hypocholesterolemia
Lecture 2- Fatty acid activation and carnitine shuttle.pptxArpitaGupte1
This document discusses lipid metabolism, specifically the multi-stage process of fatty acid utilization through beta-oxidation. It describes:
1) Fatty acids must be activated by binding to coenzyme A in the cytosol or ER membranes in an ATP-dependent process forming acyl-CoA.
2) Long chain acyl-CoAs cannot diffuse into mitochondria and are transported using carnitine, which transfers the fatty acid between CoA and its own hydroxyl group.
3) Carnitine palmitoyl transferase I and II facilitate the three step process of transferring the fatty acyl group into the mitochondrial matrix, where it is available for beta-oxidation to produce acetyl
Hormones can be classified in several ways based on their chemical composition, mechanism of action, target effects, and whether they stimulate other endocrine glands. The three main types are steroid hormones, peptide hormones, and amine hormones. Steroid hormones are lipophilic and act via nuclear receptors. Peptide hormones are hydrophilic and act through cell surface receptors and secondary messengers like cAMP. Amine hormones have properties of both peptides and steroids. Hormones also differ in their local versus general actions, kinetic versus metabolic effects, and whether they stimulate other glands via tropic hormones or act directly on tissues.
Integration of metabolism for medical schoolRavi Kiran
The document discusses how metabolism is integrated in multicellular organisms. It describes how different organs specialize in certain metabolic functions and work together to maintain energy homeostasis. The liver plays a central role in processing nutrients from the intestines and regulating fuel levels in the bloodstream. During periods of food intake, the pancreas releases insulin which promotes fuel storage, while glucagon released during fasting mobilizes glycogen and fatty acid reserves. Prolonged starvation results in the liver producing ketone bodies from fatty acids as an alternative fuel for tissues like the brain and heart.
Slide Apparato del Golgi, a cura di Catalano Michele e Galli Valerio (Corso di istologia, L.M. in medicina e chirurgia - a.a. 2011-2012)
http://medmedicine.it
Cell cycle regulation presentation by me and my colleagues. Not the Best work but still it will give a general idea about DNA damage checkpoints, roles of Cdk-Cyclin complexes, Rb proteins, ATM&ATR kinases, p51, etc.
Reference : Nature reviews & The Cell a molecular approach. (cooper)
Dr. Mina Bissell gave a presentation on extracellular matrices. She discussed how ECMs are composed of fibrous proteins and glycosaminoglycans that form an interlocking mesh. ECMs perform important functions such as providing structural support and compartmentalizing tissues. They also present signals to cells and serve as highways for cell migration. Basement membranes are a specialized ECM layer that surround epithelia and other cell types. Collagen and laminins are major ECM proteins that form intricate structures and provide strength. Mutations in these proteins can lead to diseases like osteogenesis imperfecta and muscular dystrophies.
Hormones & related bio signaling compounds (Part 1)Eneutron
This document summarizes several hormones and related compounds involved in the endocrine system. It discusses hormones released by the hypothalamus and pituitary gland, including corticotropin-releasing hormone, somatotropin-releasing hormone, somatostatin, thyrotropin-releasing hormone, and gonadotropin-releasing hormone. It also describes hormones produced by the pituitary gland, such as ACTH, MSH, prolactin, growth hormone, TSH, and LH/FSH. Additionally, it covers insulin, glucagon, thyroid hormones, parathyroid hormone, gastrointestinal hormones like gastrin and cholecystokinin, and the structures and functions of
Signal transduction and hormone receptor complexmuti ullah
This document discusses signal transduction and hormone receptor complexes. It describes how signals like antigens, growth factors, hormones, neurotransmitters and nutrients can influence protein location and cell processes. It discusses ligands that bind receptors to activate or prevent signal transduction. There are different classes of receptors including intracellular receptors, cell surface receptors, G-protein coupled receptors, receptor tyrosine kinases, and nuclear receptors. The document also summarizes the structure and function of insulin receptors and other hormone receptors, as well as the specificity, selectivity and steps of signal transduction.
This document discusses tumor suppressor genes. It begins by explaining that cancer is caused by genetic mutations, and describes the characteristic properties of cancer cells that result from these genetic changes. It then discusses two classes of genes affected in cancer - oncogenes and tumor suppressor genes. Oncogenes contribute to tumor development, while tumor suppressors support tumor development when their function is lost. The rest of the document provides details on specific tumor suppressor genes like RB, p53, PTEN, NF1, and BRCA1/2; their functions in inhibiting cell growth and proliferation; and the genetic and epigenetic mechanisms by which their inactivation can lead to cancer development.
Il presente atlante istologico è stato realizzato dagli alunni Maccaferri Ambra e Ghisellini Alberto (5R 2010-11) nell’ambito di una convenzione stipulata tra l’Istituto Bassi Burgatti e l’ Istituto Ramazzini Cooperativa Sociale Onlus - Centro di Ricerca sul Cancro "Cesare Maltoni" di Bentivoglio (BO)
Peptides and proteins structure and functionsRamesh Gupta
Peptides and proteins are polymers of amino acids. Their structure and function depend on the nature, sequence, and spatial arrangement of amino acids. Peptides generally have fewer than 100 amino acids, while proteins have 100 or more. Many peptides are formed by protein breakdown. Examples of physiologically active peptides include glutathione, bradykinin, angiotensin, vasopressin, oxytocin, and TRH. Proteins perform functions like maintaining pH and osmotic balance. They also include enzymes, hormones, and structural components of tissues.
The extracellular matrix (ECM) is a collection of molecules secreted by cells that provides structural and biochemical support to surrounding cells. It is composed of water, proteins, and polysaccharides. The ECM contains collagens, fibronectin, laminins, and proteoglycans. Collagen is the most abundant protein in the ECM and forms fibrils that provide structure. The ECM regulates cell behavior, provides tissue structure and strength, and mediates cell signaling and homeostasis. Genetic defects in ECM proteins can cause diseases like osteogenesis imperfecta or fibrosis.
Cell adhesion molecules are proteins located on cell surfaces that allow cells to adhere to each other and maintain tissue structure. The most important type are cadherins, which are calcium-dependent transmembrane proteins that connect to other cadherins on adjacent cells and link to the actin cytoskeleton. Cadherins help organize cell layers and tissues during development by promoting adhesion between similar cell types and separation between dissimilar ones. Other classes of cell adhesion molecules include integrins, IgCAMs, and selectins, which provide both calcium-dependent and calcium-independent adhesion between cells and the extracellular matrix.
This document summarizes different types of cell adhesion molecules (CAMs). It discusses cadherins, which are the primary CAMs in adherens junctions and desmosomes. Integrins are heterodimeric receptors that connect the intracellular and extracellular environments and are involved in cell adhesion to the extracellular matrix. The immunoglobulin superfamily of CAMs are calcium-independent transmembrane proteins with immunoglobulin-like domains. Selectins mediate the initial tethering of leukocytes to endothelial cells during inflammation. Cell adhesion molecules play important roles in processes like embryogenesis, immunity, tissue development, and cancer metastasis.
The document discusses the composition and function of the extracellular matrix (ECM). It is composed of cells, fibrillar proteins like collagen and elastin, proteoglycans, and structural glycoproteins. The ECM provides structural support and regulates cell behavior. Collagen is the most abundant protein and forms strong fibrils through post-translational modifications and crosslinking. Proteoglycans are heavily glycosylated proteins that contain glycosaminoglycan chains and help organize the ECM.
Intercellular connections and molecular motorsAnwar Siddiqui
This document summarizes a physiology seminar on intercellular connections and molecular motors. It discusses various cell adhesion molecules like cadherins, selectins, immunoglobulin superfamily molecules, and integrins that mediate cell-cell and cell-matrix adhesion. It also describes different types of intercellular junctions such as tight junctions, desmosomes, and hemidesmosomes. Finally, it provides an overview of molecular motors like kinesin, dynein, and myosin that transport cargo within cells and generate forces through ATP hydrolysis.
Proprietà biochimiche e strutturali delle
idrolasi acide, ceramide glicosidasi e
sfingomielinasi, il cui deficit funzionale è
alla base rispettivamente della malattia di Gaucher e di Niemann-Pick.
Esiti esame Bioch Siste Umana del 23.01.2017.
Chi volesse rifiutare il voto: scrivere una mail a francesca.re1@unimib.it entro venedì sera. poi i voti saranno registrati senza possibilità di cambiamenti.
Esito esame Biochimica Sist Umana del 13 dicembre 2016.
SOLO chi RIFIUTA il voto: scrivetemi una mail entro domani alle 12. POI i voti saranno registrati.
Proposte stage 2016-2017. In verde: studenti e relativi periodi GIA' ASSEGNATI.
In giallo: studenti e periodi disponibili ANCORA DA CONFERMARE.
I gialli dovrebbero farmi sapere (VIA MAIL) la loro decisione al più presto per eventuale liberazione di posti. grazie.
1. ORMONI
Il controllo e la coordinazione dei
processi biologici sono ottenuti
attraverso messaggeri chimici
2. Il sistema endocrino
è deputato all'invio di "messaggi" ai
vari organi e tessuti dell'organismo
GHIANDOLE ENDOCRINE
(senza dotto escretore)
GHIANDOLE ESOCRINE
(con dotto escretore)
Sistema neuroendocrino
3.
4. Le funzioni biologiche degli ormoni si svolgono con tre diversi meccanismi:
ENDOCRINO = l’ormone prodotto a livello della ghiandola endocrina raggiunge il
tessuto bersaglio tramite il torrente circolatorio
PARACRINO = l’ormone prodotto a livello della ghiandola endocrina raggiunge il
tessuto bersaglio tramite il liquido extra-cellulare
AUTOCRINO = l’ormone prodotto a livello della ghiandola endocrina ha effetto
sulle stesse cellule che l’hanno prodotto
5.
6. FUNZIONI DEGLI ORMONI
1. Regolazione processi metabolici
2. Controllo crescita, differenziamento
cellulare, processi riproduttivi
3. Controllo apprendimento e memoria
4. Risposta ai cambiamenti ambientali
7. Praticamente TUTTI i processi metabolici sono
controllati e coordinati da uno o più ormoni
ALCUNI ESEMPI:
Pressione sanguigna e bilancio elettrolitico
Differenziamento sessuale, sviluppo e
riproduzione
Regolazione del metabolismo energetico
8. Meccanismo d’azione
degli ormoni
1. Secrezione di ormoni da
cellule specializzate
ormone
blood
2. Trasporto in circolo
3. Raggiungimento della cellula bersaglio
(cellula che risponde all’azione di un dato ormone)
Cellula bersaglio
4. Trasduzione del segnale
Metabolismo Espressione genica
GHIANDOLA
Trasduzione del segnale
Recettore>>>Trasduttore>>>Effettore
SINTESI DI ORMONI
9. TIPI DI ORMONI
1. Ormoni steroidei
2. Ormoni derivati da amminoacidi
3. Ormoni peptidici/polipeptidici
11. ANABOLIZZANTI:
Steroidi anabolizzanti sono usati
illegalmente per migliorare le prestazioni
atletiche (hanno effetti sulla biosintesi
delle proteine)
Un anabolizzante è una sostanza chimica che aumenta l'anabolismo, ossia che stimola la formazione di molecole complesse
(proteine, lipidi complessi e polisaccaridi) a partire da molecole semplici (rispettivamente amminoacidi, acidi grassi e monosaccaridi).
16. Biosintesi ormoni peptidici
1. Sequenza segnale:
indirizzamento verso i granuli
di secrezione e rilascio
extracellulare
2. Sintetizzati come precursori
inattivi: pre-pro-ormone
(attivati per proteolisi)
3. Un singolo pre-pro-ormone
può dar luogo a diversi
ormoni
17. Meccanismo d’azione
degli ormoni
1. Secrezione di ormoni da
cellule specializzate
ormone
blood
2. Trasporto in circolo
3. Raggiungimento della cellula bersaglio
(cellula che risponde all’azione di un dato ormone)
Cellula bersaglio
4. Trasduzione del segnale
Metabolismo Espressione genica
GHIANDOLA
Trasduzione del segnale
Recettore>>>Trasduttore>>>Effettore
TRASPORTO DI ORMONI
19. Meccanismo d’azione
degli ormoni
1. Secrezione di ormoni da
cellule specializzate
ormone
blood
2. Trasporto in circolo
3. Raggiungimento della cellula bersaglio
(cellula che risponde all’azione di un dato ormone)
Cellula bersaglio
4. Trasduzione del segnale
Metabolismo Espressione genica
GHIANDOLA
Trasduzione del segnale
Recettore>>>Trasduttore>>>Effettore
INTERAZIONE CON LA
CELLULA BERSAGLIO
24. I RECETTORI PER GLI ORMONI STEROIDEI
•Si trovano nel compartimento intracellulare
•Il complesso ormone-recettore si lega al DNA attivando uno o più geni
•L’mRNA dirige la sintesi di nuove proteine
25. I RECETTORI PER GLI ORMONI PEPTIDICI
Sono situati sulla membrana cellulare
Determinano la sintesi di secondi messaggeri (cAMP, cGMP, DAG, Ca++)
I secondi messaggeri determinano modificazioni enzimatiche dentro la cellula
26. TIPI DI RECETTORI
Recettori accoppiati a proteine G
Recettori catalitici con un singolo
dominio TM (1-TMS)
Canali ionici oligomerici
27. 7 domini transmembrana
ad a-elica
L’ormone si lega nella tasca
idrofobica inducendo un
cambiamento conformazionale
Es. ADRENALINA
Il cambiamento conformazionale
del recettore attiva la proteina G
28. Porta alla generazione di secondi messaggeri:
cAMP
+ fosfolipasi
Ca2+
PROTEINA G
Eterotrimero
GDP: forma inattiva
GTP: forma attiva
TRASDUZIONE
DEL SEGNALE
SECONDO MESSAGGERO
PRIMO MESSAGGERO
29. GTP/GDP
Il guanosintrifosfato o GTP è un ribonucleotide trifosfato
formato da:
guanina(una base azotata)
ribosio (uno zuccheropentoso)
tre gruppi fosfato
30. La sintesi o il rilascio di un secondo
messaggero è seguita dalla sua rapida
degradazione o rimozione dal citosol
Tutti i secondi messaggeri esercitano i
loro effetti sulla cellula legandosi a una o
più molecole bersaglio
31. BERSAGLI PER LE PROTEINE G
adenil ciclasi: l'enzima responsabile della
formazione del cAMP
fosfolipasi C: l'enzima responsabile della
formazione dell'inositolo trifosfato e del
diacilglicerolo
canali ionici: in particolare i canali del calcio e del
potassio.
46. TIPI DI RECETTORI
Recettori accoppiati a proteine G
Recettori catalitici con un singolo
dominio TM (1-TMS)
Canali ionici oligomerici
47. CANALI IONICI LIGANDO-DIPENDENTI
sono recettori le cui subunità costitutive racchiudono un poro
attraverso il quale avviene il flusso di ioni
Assenza di ligando: sono presenti in una
conformazione strutturale che ostruisce il
poro, impedendo il flusso di ioni.
Presenza di ligando: il recettore cambia la
conformazione strutturale e aprendosi
permettendo agli ioni di attraversare la
membrana.
48. Il legame con il ligando provoca un cambiamento conformazionale dell'N-terminale del
recettore che, causando la dimerizzazione dei domini extracellulari, permette la
diffusione laterale dei domini citoplasmatici, consentendo quindi il contatto tra i C-terminali
e attivando l'attività chinasica.
La dimerizzazione innesca quindi un processo di autofosforilazione, in cui l'attività
chinasica di ogni recettore monomerico fosforila residui dell'altro. Inizialmente vengono
fosforilati i residui di tirosina del labbro di fosforilazione, situato in prossimità del sito
attivo. Questo causa lo spostamento di quest'ansa di attivazione dal sito catalitico,
favorendo così il legame dell'ATP in alcune proteine, direttamente delle proteine
substrato in altre. Successivamente vengono fosforilati altri residui dei domini
citoplasmatici, fornendo il sito d'attacco per le proteine substrato.
