G-protein coupled receptors (GPCRs) are the largest family of membrane receptors that are linked to intracellular effector proteins via G-protein activation. There are several classes of GPCRs classified based on sequence homology. All GPCRs have seven transmembrane domains and signal through heterotrimeric G proteins. When a ligand binds a GPCR, it activates an associated G protein which then regulates downstream effectors like adenylyl cyclase or phospholipase C. These pathways mediate many physiological processes such as vision, smell, immune response, and neuronal signaling.
This document discusses second messengers, which are intracellular molecules that amplify and spread signals from receptors on the cell surface. It describes four main classes of second messengers - cyclic nucleotides, membrane lipid derivatives, calcium ions, and gases like nitric oxide. Specifically, it examines the cAMP, cGMP, IP3/DAG, and calcium-mediated signaling pathways, outlining the ligands, effectors, and downstream effects of each messenger. It also provides details on nitric oxide and calcium signaling within cells.
Transmembrane ion channels are protein pores that regulate the passage of ions across cell membranes. There are two main types - voltage-gated ion channels, which open and close in response to changes in membrane potential, and ligand-gated ion channels, which open when certain chemical messengers bind to them. Key voltage-gated channels include sodium, calcium, and potassium channels. Major ligand-gated channels are nicotinic acetylcholine receptors, GABAA receptors, glutamate receptors, and ATP-sensitive potassium channels. The discovery and study of ion channels over time has provided crucial insights into nerve signaling and other cellular processes.
The document summarizes the JAK-STAT signaling pathway. It discusses how the pathway consists of receptors, Janus kinases (JAKs), and Signal Transducers and Activators of Transcription (STATs). When a ligand binds to a receptor, it activates associated JAKs which phosphorylate STATs. Phosphorylated STATs form dimers and translocate to the nucleus to regulate gene transcription. The pathway is negatively regulated by phosphatases, suppressors of cytokine signaling, and protein inhibitors of activated STATs. Experiments using STAT knockout cells and mice have helped elucidate the specific roles and regulation of the pathway.
Ion channels are membrane proteins that allow ions to pass through their pore, regulating ion flow and electrical signals. There are two main types of gated ion channels: ligand-gated channels, which open when neurotransmitters bind, and voltage-gated channels, which open in response to changes in membrane potential. Ligand-gated channels allow sodium influx upon acetylcholine binding, depolarizing the membrane and triggering action potentials. Voltage-gated channels maintain the resting potential and enable action potential propagation along axons by selectively transporting sodium, potassium, calcium, and chloride ions in response to changes in voltage.
G-protein coupled receptors (GPCRs) are integral membrane proteins that detect molecules outside the cell and activate internal signal transduction pathways. They have seven transmembrane domains and couple with G proteins. Ligand binding causes a conformational change in the receptor that activates the G protein, starting signaling cascades. The main signaling pathways are cAMP, phosphatidylinositol, and Rho/ROCK. GPCRs mediate many physiological processes like vision, smell, immune response, and homeostasis. They are also involved in many diseases and are drug targets.
Intercellular and intracellular cell signaling pathwaySachinGulia12
This document summarizes intercellular and intracellular signaling pathways. It describes four types of intercellular signaling: autocrine, paracrine, endocrine, and juxtacrine. Intracellular signaling pathways involve signal transduction after a ligand binds to a cell surface receptor. Examples of intracellular pathways discussed are G protein-coupled receptors, enzyme-linked receptors, ligand-gated ion channels, and second messenger pathways like cyclic AMP. The document provides details on the mechanisms and key steps in several of these signaling pathways.
Second messengers are intracellular signaling molecules that are released within cells in response to extracellular first messengers like hormones and neurotransmitters. They amplify and propagate intracellular signals. Examples include cyclic AMP (cAMP), cyclic GMP (cGMP), inositol trisphosphate, and calcium. cAMP and cGMP are produced from ATP and GTP by adenylate and guanylate cyclases, respectively. They activate downstream effector proteins like protein kinase A and G. This leads to phosphorylation of various target proteins and physiological responses like metabolism, gene expression, cell survival, proliferation and apoptosis. The document discusses the mechanisms, targets, functions and therapeutic applications of cAMP and cGMP second messenger systems in detail.
G-protein coupled receptors (GPCRs) are the largest family of membrane receptors that are linked to intracellular effector proteins via G-protein activation. There are several classes of GPCRs classified based on sequence homology. All GPCRs have seven transmembrane domains and signal through heterotrimeric G proteins. When a ligand binds a GPCR, it activates an associated G protein which then regulates downstream effectors like adenylyl cyclase or phospholipase C. These pathways mediate many physiological processes such as vision, smell, immune response, and neuronal signaling.
This document discusses second messengers, which are intracellular molecules that amplify and spread signals from receptors on the cell surface. It describes four main classes of second messengers - cyclic nucleotides, membrane lipid derivatives, calcium ions, and gases like nitric oxide. Specifically, it examines the cAMP, cGMP, IP3/DAG, and calcium-mediated signaling pathways, outlining the ligands, effectors, and downstream effects of each messenger. It also provides details on nitric oxide and calcium signaling within cells.
Transmembrane ion channels are protein pores that regulate the passage of ions across cell membranes. There are two main types - voltage-gated ion channels, which open and close in response to changes in membrane potential, and ligand-gated ion channels, which open when certain chemical messengers bind to them. Key voltage-gated channels include sodium, calcium, and potassium channels. Major ligand-gated channels are nicotinic acetylcholine receptors, GABAA receptors, glutamate receptors, and ATP-sensitive potassium channels. The discovery and study of ion channels over time has provided crucial insights into nerve signaling and other cellular processes.
The document summarizes the JAK-STAT signaling pathway. It discusses how the pathway consists of receptors, Janus kinases (JAKs), and Signal Transducers and Activators of Transcription (STATs). When a ligand binds to a receptor, it activates associated JAKs which phosphorylate STATs. Phosphorylated STATs form dimers and translocate to the nucleus to regulate gene transcription. The pathway is negatively regulated by phosphatases, suppressors of cytokine signaling, and protein inhibitors of activated STATs. Experiments using STAT knockout cells and mice have helped elucidate the specific roles and regulation of the pathway.
Ion channels are membrane proteins that allow ions to pass through their pore, regulating ion flow and electrical signals. There are two main types of gated ion channels: ligand-gated channels, which open when neurotransmitters bind, and voltage-gated channels, which open in response to changes in membrane potential. Ligand-gated channels allow sodium influx upon acetylcholine binding, depolarizing the membrane and triggering action potentials. Voltage-gated channels maintain the resting potential and enable action potential propagation along axons by selectively transporting sodium, potassium, calcium, and chloride ions in response to changes in voltage.
G-protein coupled receptors (GPCRs) are integral membrane proteins that detect molecules outside the cell and activate internal signal transduction pathways. They have seven transmembrane domains and couple with G proteins. Ligand binding causes a conformational change in the receptor that activates the G protein, starting signaling cascades. The main signaling pathways are cAMP, phosphatidylinositol, and Rho/ROCK. GPCRs mediate many physiological processes like vision, smell, immune response, and homeostasis. They are also involved in many diseases and are drug targets.
Intercellular and intracellular cell signaling pathwaySachinGulia12
This document summarizes intercellular and intracellular signaling pathways. It describes four types of intercellular signaling: autocrine, paracrine, endocrine, and juxtacrine. Intracellular signaling pathways involve signal transduction after a ligand binds to a cell surface receptor. Examples of intracellular pathways discussed are G protein-coupled receptors, enzyme-linked receptors, ligand-gated ion channels, and second messenger pathways like cyclic AMP. The document provides details on the mechanisms and key steps in several of these signaling pathways.
Second messengers are intracellular signaling molecules that are released within cells in response to extracellular first messengers like hormones and neurotransmitters. They amplify and propagate intracellular signals. Examples include cyclic AMP (cAMP), cyclic GMP (cGMP), inositol trisphosphate, and calcium. cAMP and cGMP are produced from ATP and GTP by adenylate and guanylate cyclases, respectively. They activate downstream effector proteins like protein kinase A and G. This leads to phosphorylation of various target proteins and physiological responses like metabolism, gene expression, cell survival, proliferation and apoptosis. The document discusses the mechanisms, targets, functions and therapeutic applications of cAMP and cGMP second messenger systems in detail.
Dr. Pavani discusses G protein-coupled receptors (GPCRs), which are integral membrane proteins that sense molecules outside the cell and activate internal signal transduction pathways and cellular responses. There are over 800 GPCRs in humans that detect a wide range of ligands and are involved in many physiological processes. GPCRs work by coupling to G proteins, which activate various intracellular effectors like adenylyl cyclase, phospholipase C, and ion channels. Dysregulation of GPCR signaling can lead to many human diseases. Martin Rodbell and Alfred Gilman were awarded the 1994 Nobel Prize in Physiology or Medicine for their discoveries related to G proteins and GPCR signal transduction.
The JAK-STAT signaling pathway transmits signals from extracellular chemicals to the nucleus, activating transcription of target genes. It consists of a cell surface receptor, associated Janus kinases (JAKs), and signal transducers and activators of transcription (STATs). When a ligand binds the receptor, JAKs phosphorylate STATs, which form dimers and translocate to the nucleus to regulate gene expression. The Ras/MAPK pathway similarly relays signals from cell surface receptors via Ras, Raf, MEK, and MAPK proteins to influence transcription. Both pathways are tightly regulated and important for processes like cell growth, differentiation, and apoptosis, with dysregulation contributing to diseases.
Cyclic adenosine monophosphate (cAMP) is an important second messenger in intracellular signal transduction. It is derived from ATP and conveys signals from hormones that bind to cell surface receptors. Many hormones such as epinephrine, glucagon, and others activate adenylate cyclase, which produces cAMP from ATP. cAMP then activates protein kinase A and triggers physiological responses in the cell. The effects of cAMP are terminated by phosphodiesterases that break it down or by phosphatases dephosphorylating protein kinase A. Deregulation of cAMP pathways has been implicated in cancer and cognitive disorders.
The document discusses G-protein coupled receptors (GPCRs), which comprise the largest group of proteins in mammals. GPCRs have 7 transmembrane domains and signal from outside the cell to the interior by coupling to G proteins. They are involved in many human biological processes and about 45% of pharmaceutical drugs target GPCRs. GPCRs activate different intracellular signaling pathways upon ligand binding, including the cAMP pathway, IP3-DAG pathway, and channel regulation pathways, mediated by different G protein subunits.
G protein coupled receptors and their Signaling MechanismFarazaJaved
G protein-coupled receptors (GPCRs) are a large family of receptors that span cell membranes and activate intracellular signaling pathways in response to extracellular stimuli. They are activated by a wide range of ligands including light, hormones, and neurotransmitters. Upon ligand binding, GPCRs activate heterotrimeric G proteins, which then initiate intracellular signaling cascades. The three main G protein families - Gs, Gi, and Gq - activate or inhibit different downstream effector enzymes to elicit a cellular response. Dysregulation of GPCRs and their associated signaling pathways can lead to various diseases.
This document discusses the different types of receptors:
1) Ligand-gated ion channels directly open ion channels in response to neurotransmitters.
2) G-protein coupled receptors activate intracellular second messenger systems through G-proteins.
3) Kinase-linked receptors activate intracellular protein kinases.
4) Nuclear receptors regulate gene transcription by binding to DNA response elements as dimers.
Classification of receptors family by vivek sharmaAnimatedWorld
Definition- Receptor are the biologic molecule to which drug bind and produces a measurable response.
So, enzyme and structural proteins can be considerd to be pharmacologic receptors.
Majorly receptor are of 4 types and the molecule or a drug interact to receptor to give response often called as ligand.
The type of receptor a ligand will bind is depend on the nature of ligand.
Hydrophilliic ligand binds to the receptor found on the cell surface.
Hydrophobic ligand can enter the cell membrane to intract the receptor present on inside the cells.
Classification of Receptors
A. Cell surface receptor
Ligand-gated Ion Channel
G Protein Coupled Receptor
Enzyme linked Receptor
B. Intracellular Receptor
Nuclear Receptor
The document summarizes ion channels and ion channel receptors. It discusses several key points:
1) Ion channels transport specific ions across cell membranes and generate electrical signals. Voltage-gated and ligand-gated ion channels open and close in response to changes in membrane potential or ligand binding.
2) Common types of ion channels include voltage-gated sodium, potassium, and calcium channels, as well as ligand-gated channels like GABA, glycine, and glutamate receptors.
3) Ion channels play important physiological roles in nerve impulse conduction, muscle contraction, and other processes. Dysfunctions can lead to channelopathies and medical conditions. Many drugs target ion channels.
This document discusses G-protein coupled receptors (GPCRs):
- GPCRs are the largest family of transmembrane receptors and play important roles in human senses and physiology. They respond to a wide range of ligands.
- GPCRs are classified into families based on sequence homology and functional similarity. The largest family is rhodopsin-like receptors which have 7 transmembrane domains.
- GPCRs are activated via conformational changes in the transmembrane domains, primarily involving movements of "microswitches" that allow the receptor to activate associated G proteins and downstream signaling.
G-protein coupled receptors (GPCRs) are the largest family of membrane receptors and the target of many drugs. They have seven transmembrane domains and signal through G proteins and second messengers like cAMP or IP3. Upon ligand binding, the GPCR activates a G protein that then activates or inhibits downstream effectors to produce a cellular response. GPCRs regulate many physiological functions and half of all drugs target these receptors. Recent research focuses on deorphaning orphan GPCRs and understanding how GPCR mutations can cause disease.
G protein coupled receptors (GPCRs) are a large family of cell membrane receptors that are linked to intracellular effector proteins. All GPCRs have seven transmembrane alpha helical segments. The receptors activate intracellular signaling pathways upon binding of an agonist ligand. This leads to the exchange of GDP for GTP on associated G proteins, which then activate downstream effectors to induce cellular responses. The major effector pathways activated by GPCRs are adenylyl cyclase/cAMP, phospholipase C/IP3-DAG, and ion channel regulation.
Earl Wilbur Sutherland Jr. discovered cyclic AMP (cAMP) as a second messenger that allows hormones like epinephrine to trigger physiological responses in cells. cAMP is produced from ATP by adenylate cyclase in response to hormone binding and activates protein kinase A. Protein kinase A then phosphorylates other proteins to initiate downstream cellular effects. The actions of cAMP are terminated by phosphodiesterase breaking it down and by dephosphorylation of proteins. cAMP mediates many important processes like glycogen breakdown and gene transcription.
GPCRs are the most dynamic and most abundant all the receptors. The G protein-coupled receptor (GPCR) superfamily comprises the largest and most diverse group of proteins in mammals. GPCRs are responsible for every aspect of human biology from vision, taste, sense of smell, sympathetic and parasympathetic nervous functions, metabolism, and immune regulation to reproduction. GPCRs interact with a number of ligands ranging from photons, ions, amino acids, odorants, pheromones, eicosanoids, neurotransmitters, peptides, proteins, and hormones.
Nevertheless, for the majority of GPCRs, the identity of their natural ligands is still unknown, hence remain orphan receptors.
The simple dogma that underpins much of our current understanding of GPCRs, namely,
one GPCR gene− one GPCR protein− one functional GPCR− one G protein −one response
is showing distinct signs of wear.
Second messengers are small intracellular molecules that amplify signals received at cell surface receptors and help transmit them to target molecules inside the cell. The document discusses four main classes of second messengers - cyclic nucleotides, membrane lipid derivatives, calcium ions, and gases like nitric oxide. It provides details on several important second messengers, including cAMP, cGMP, IP3, DAG, and calcium ions, and how they mediate intracellular signaling pathways and cellular responses.
This document discusses glutamate receptors, including their history, types, roles, and drugs that act on them. It notes that glutamate is the major excitatory neurotransmitter in the central nervous system. There are two main types of glutamate receptors: ionotropic receptors which are ligand-gated ion channels including NMDA, AMPA, and kainate receptors, and metabotropic G protein-coupled receptors divided into groups 1, 2, and 3. The roles of glutamate receptors include synaptic plasticity, learning and memory, and excitotoxicity. Many drugs have been developed that act as agonists or antagonists at glutamate receptors and are being investigated for conditions like Alzheimer's, Parkinson
G-protein coupled receptors (GPCRs) are integral membrane proteins that interact with extracellular signaling molecules and activate intracellular signaling pathways. There are over 1000 known GPCRs that are classified into three main families based on sequence homology. Upon agonist binding, GPCRs activate heterotrimeric G proteins located on the intracellular side of the cell membrane, initiating downstream signaling cascades such as the cAMP pathway or phospholipase C pathway. GPCRs play key roles in many physiological processes and are the targets of about 40% of all modern medicinal drugs.
Neurotransmission (Latin: transmission "passage, crossing" from transmitter "send, let through"), is the process by which signalling molecules called neurotransmitters are released by the axon terminal of a neuron and bind to and react with the receptors on the dendrites of another neuron
1. Second messengers are small intracellular molecules that transmit signals within cells after extracellular signaling molecules (hormones or neurotransmitters) bind to cell surface receptors.
2. There are three main types of second messenger systems: cyclic AMP (cAMP), cyclic GMP (cGMP), and inositol trisphosphate (IP3)/diacylglycerol (DAG). These systems activate protein kinases or trigger the release of calcium ions to produce a physiological response.
3. Second messengers amplify and diversify extracellular signals, allowing for precise regulation of multiple cellular processes. Their roles are important for understanding cell signaling, disease mechanisms, and potential drug targets.
This document discusses receptors and their downstream signaling pathways, including JAK-STAT and MAPK pathways. It defines receptors and describes different receptor types like G protein-coupled and enzyme-linked receptors. It then focuses on the JAK-STAT pathway, identifying its components like JAK kinases and STAT transcription factors, and drugs that target this pathway for conditions like rheumatoid arthritis. Finally, it examines the MAPK pathway, identifying the MAP kinase families involved in key cellular processes and examples of drugs that inhibit parts of this pathway.
1. Toxicology is the study of the biochemical and physiological effects of toxicants on the body and their mechanisms of action, focusing on interactions with target sites. Two factors that determine effect are affinity, how tightly a toxicant binds to a receptor, and intrinsic activity, its ability to activate the receptor and produce a cellular response.
2. Receptors are membrane proteins that toxicants bind to in order to produce effects. There are four main classes of receptors: ligand-gated ion channels, G-protein coupled receptors, enzymatic receptors, and receptors that regulate DNA transcription.
3. G-protein coupled receptors are the largest family and activate distinct effector proteins through G-proteins. Their activation
Dr. Pavani discusses G protein-coupled receptors (GPCRs), which are integral membrane proteins that sense molecules outside the cell and activate internal signal transduction pathways and cellular responses. There are over 800 GPCRs in humans that detect a wide range of ligands and are involved in many physiological processes. GPCRs work by coupling to G proteins, which activate various intracellular effectors like adenylyl cyclase, phospholipase C, and ion channels. Dysregulation of GPCR signaling can lead to many human diseases. Martin Rodbell and Alfred Gilman were awarded the 1994 Nobel Prize in Physiology or Medicine for their discoveries related to G proteins and GPCR signal transduction.
The JAK-STAT signaling pathway transmits signals from extracellular chemicals to the nucleus, activating transcription of target genes. It consists of a cell surface receptor, associated Janus kinases (JAKs), and signal transducers and activators of transcription (STATs). When a ligand binds the receptor, JAKs phosphorylate STATs, which form dimers and translocate to the nucleus to regulate gene expression. The Ras/MAPK pathway similarly relays signals from cell surface receptors via Ras, Raf, MEK, and MAPK proteins to influence transcription. Both pathways are tightly regulated and important for processes like cell growth, differentiation, and apoptosis, with dysregulation contributing to diseases.
Cyclic adenosine monophosphate (cAMP) is an important second messenger in intracellular signal transduction. It is derived from ATP and conveys signals from hormones that bind to cell surface receptors. Many hormones such as epinephrine, glucagon, and others activate adenylate cyclase, which produces cAMP from ATP. cAMP then activates protein kinase A and triggers physiological responses in the cell. The effects of cAMP are terminated by phosphodiesterases that break it down or by phosphatases dephosphorylating protein kinase A. Deregulation of cAMP pathways has been implicated in cancer and cognitive disorders.
The document discusses G-protein coupled receptors (GPCRs), which comprise the largest group of proteins in mammals. GPCRs have 7 transmembrane domains and signal from outside the cell to the interior by coupling to G proteins. They are involved in many human biological processes and about 45% of pharmaceutical drugs target GPCRs. GPCRs activate different intracellular signaling pathways upon ligand binding, including the cAMP pathway, IP3-DAG pathway, and channel regulation pathways, mediated by different G protein subunits.
G protein coupled receptors and their Signaling MechanismFarazaJaved
G protein-coupled receptors (GPCRs) are a large family of receptors that span cell membranes and activate intracellular signaling pathways in response to extracellular stimuli. They are activated by a wide range of ligands including light, hormones, and neurotransmitters. Upon ligand binding, GPCRs activate heterotrimeric G proteins, which then initiate intracellular signaling cascades. The three main G protein families - Gs, Gi, and Gq - activate or inhibit different downstream effector enzymes to elicit a cellular response. Dysregulation of GPCRs and their associated signaling pathways can lead to various diseases.
This document discusses the different types of receptors:
1) Ligand-gated ion channels directly open ion channels in response to neurotransmitters.
2) G-protein coupled receptors activate intracellular second messenger systems through G-proteins.
3) Kinase-linked receptors activate intracellular protein kinases.
4) Nuclear receptors regulate gene transcription by binding to DNA response elements as dimers.
Classification of receptors family by vivek sharmaAnimatedWorld
Definition- Receptor are the biologic molecule to which drug bind and produces a measurable response.
So, enzyme and structural proteins can be considerd to be pharmacologic receptors.
Majorly receptor are of 4 types and the molecule or a drug interact to receptor to give response often called as ligand.
The type of receptor a ligand will bind is depend on the nature of ligand.
Hydrophilliic ligand binds to the receptor found on the cell surface.
Hydrophobic ligand can enter the cell membrane to intract the receptor present on inside the cells.
Classification of Receptors
A. Cell surface receptor
Ligand-gated Ion Channel
G Protein Coupled Receptor
Enzyme linked Receptor
B. Intracellular Receptor
Nuclear Receptor
The document summarizes ion channels and ion channel receptors. It discusses several key points:
1) Ion channels transport specific ions across cell membranes and generate electrical signals. Voltage-gated and ligand-gated ion channels open and close in response to changes in membrane potential or ligand binding.
2) Common types of ion channels include voltage-gated sodium, potassium, and calcium channels, as well as ligand-gated channels like GABA, glycine, and glutamate receptors.
3) Ion channels play important physiological roles in nerve impulse conduction, muscle contraction, and other processes. Dysfunctions can lead to channelopathies and medical conditions. Many drugs target ion channels.
This document discusses G-protein coupled receptors (GPCRs):
- GPCRs are the largest family of transmembrane receptors and play important roles in human senses and physiology. They respond to a wide range of ligands.
- GPCRs are classified into families based on sequence homology and functional similarity. The largest family is rhodopsin-like receptors which have 7 transmembrane domains.
- GPCRs are activated via conformational changes in the transmembrane domains, primarily involving movements of "microswitches" that allow the receptor to activate associated G proteins and downstream signaling.
G-protein coupled receptors (GPCRs) are the largest family of membrane receptors and the target of many drugs. They have seven transmembrane domains and signal through G proteins and second messengers like cAMP or IP3. Upon ligand binding, the GPCR activates a G protein that then activates or inhibits downstream effectors to produce a cellular response. GPCRs regulate many physiological functions and half of all drugs target these receptors. Recent research focuses on deorphaning orphan GPCRs and understanding how GPCR mutations can cause disease.
G protein coupled receptors (GPCRs) are a large family of cell membrane receptors that are linked to intracellular effector proteins. All GPCRs have seven transmembrane alpha helical segments. The receptors activate intracellular signaling pathways upon binding of an agonist ligand. This leads to the exchange of GDP for GTP on associated G proteins, which then activate downstream effectors to induce cellular responses. The major effector pathways activated by GPCRs are adenylyl cyclase/cAMP, phospholipase C/IP3-DAG, and ion channel regulation.
Earl Wilbur Sutherland Jr. discovered cyclic AMP (cAMP) as a second messenger that allows hormones like epinephrine to trigger physiological responses in cells. cAMP is produced from ATP by adenylate cyclase in response to hormone binding and activates protein kinase A. Protein kinase A then phosphorylates other proteins to initiate downstream cellular effects. The actions of cAMP are terminated by phosphodiesterase breaking it down and by dephosphorylation of proteins. cAMP mediates many important processes like glycogen breakdown and gene transcription.
GPCRs are the most dynamic and most abundant all the receptors. The G protein-coupled receptor (GPCR) superfamily comprises the largest and most diverse group of proteins in mammals. GPCRs are responsible for every aspect of human biology from vision, taste, sense of smell, sympathetic and parasympathetic nervous functions, metabolism, and immune regulation to reproduction. GPCRs interact with a number of ligands ranging from photons, ions, amino acids, odorants, pheromones, eicosanoids, neurotransmitters, peptides, proteins, and hormones.
Nevertheless, for the majority of GPCRs, the identity of their natural ligands is still unknown, hence remain orphan receptors.
The simple dogma that underpins much of our current understanding of GPCRs, namely,
one GPCR gene− one GPCR protein− one functional GPCR− one G protein −one response
is showing distinct signs of wear.
Second messengers are small intracellular molecules that amplify signals received at cell surface receptors and help transmit them to target molecules inside the cell. The document discusses four main classes of second messengers - cyclic nucleotides, membrane lipid derivatives, calcium ions, and gases like nitric oxide. It provides details on several important second messengers, including cAMP, cGMP, IP3, DAG, and calcium ions, and how they mediate intracellular signaling pathways and cellular responses.
This document discusses glutamate receptors, including their history, types, roles, and drugs that act on them. It notes that glutamate is the major excitatory neurotransmitter in the central nervous system. There are two main types of glutamate receptors: ionotropic receptors which are ligand-gated ion channels including NMDA, AMPA, and kainate receptors, and metabotropic G protein-coupled receptors divided into groups 1, 2, and 3. The roles of glutamate receptors include synaptic plasticity, learning and memory, and excitotoxicity. Many drugs have been developed that act as agonists or antagonists at glutamate receptors and are being investigated for conditions like Alzheimer's, Parkinson
G-protein coupled receptors (GPCRs) are integral membrane proteins that interact with extracellular signaling molecules and activate intracellular signaling pathways. There are over 1000 known GPCRs that are classified into three main families based on sequence homology. Upon agonist binding, GPCRs activate heterotrimeric G proteins located on the intracellular side of the cell membrane, initiating downstream signaling cascades such as the cAMP pathway or phospholipase C pathway. GPCRs play key roles in many physiological processes and are the targets of about 40% of all modern medicinal drugs.
Neurotransmission (Latin: transmission "passage, crossing" from transmitter "send, let through"), is the process by which signalling molecules called neurotransmitters are released by the axon terminal of a neuron and bind to and react with the receptors on the dendrites of another neuron
1. Second messengers are small intracellular molecules that transmit signals within cells after extracellular signaling molecules (hormones or neurotransmitters) bind to cell surface receptors.
2. There are three main types of second messenger systems: cyclic AMP (cAMP), cyclic GMP (cGMP), and inositol trisphosphate (IP3)/diacylglycerol (DAG). These systems activate protein kinases or trigger the release of calcium ions to produce a physiological response.
3. Second messengers amplify and diversify extracellular signals, allowing for precise regulation of multiple cellular processes. Their roles are important for understanding cell signaling, disease mechanisms, and potential drug targets.
This document discusses receptors and their downstream signaling pathways, including JAK-STAT and MAPK pathways. It defines receptors and describes different receptor types like G protein-coupled and enzyme-linked receptors. It then focuses on the JAK-STAT pathway, identifying its components like JAK kinases and STAT transcription factors, and drugs that target this pathway for conditions like rheumatoid arthritis. Finally, it examines the MAPK pathway, identifying the MAP kinase families involved in key cellular processes and examples of drugs that inhibit parts of this pathway.
1. Toxicology is the study of the biochemical and physiological effects of toxicants on the body and their mechanisms of action, focusing on interactions with target sites. Two factors that determine effect are affinity, how tightly a toxicant binds to a receptor, and intrinsic activity, its ability to activate the receptor and produce a cellular response.
2. Receptors are membrane proteins that toxicants bind to in order to produce effects. There are four main classes of receptors: ligand-gated ion channels, G-protein coupled receptors, enzymatic receptors, and receptors that regulate DNA transcription.
3. G-protein coupled receptors are the largest family and activate distinct effector proteins through G-proteins. Their activation
This document provides an overview of signal transduction mechanisms. It discusses various types of receptors including G protein-coupled receptors, receptor tyrosine kinases, integrins, toll-like receptors and ligand-gated ion channels. It describes how extracellular ligands bind to cell surface receptors and initiate intracellular signaling pathways such as the cAMP pathway and phosphatidylinositol pathway. Defects in these signaling pathways can lead to diseases. The document provides details on the mechanisms of G protein-coupled receptor signaling and downstream effects.
Receptors are binding sites located on cells that bind specific molecules and initiate responses. There are several types of receptors including ionotropic receptors that act as ligand-gated ion channels, G protein-coupled receptors that activate intracellular signaling pathways via G proteins, and intracellular or nuclear receptors that directly influence gene expression. Receptor binding involves various interaction forces and leads to responses by altering cellular functions. Understanding receptor pharmacology is crucial for explaining how drugs produce their effects.
RECEPTORS and its FAMILIES, Detailed PharmacologyAswin Palanisamy
Receptors are macromolecules that bind ligands like drugs and initiate a cellular response. There are several types of receptors including G-protein coupled receptors (GPCRs), ligand gated ion channels, kinase-linked receptors, and nuclear receptors. GPCRs are the largest family and signal through G proteins to regulate effectors like adenylyl cyclase. Ligand gated ion channels directly open or close ion channels. Kinase receptors have enzymatic activity and regulate transcription. Nuclear receptors directly bind DNA to regulate gene expression. Receptors play a key role in many physiological and pharmacological processes.
This document summarizes 5 major categories of transducer mechanisms:
1) G-protein coupled receptors which activate downstream effectors like adenylyl cyclase or phospholipase C.
2) Ion channel receptors which directly open or close ion channels.
3) Transmembrane enzyme-linked receptors which activate intracellular protein kinases.
4) Transmembrane JAK-STAT binding receptors which activate the JAK/STAT signaling pathway.
5) Receptors regulating gene expression which bind intracellularly to directly regulate gene transcription.
G protein coupled receptor and pharmacotherapeuticspriyanka527
This document provides an overview of G-protein coupled receptors (GPCRs) and their role in cell signaling. It discusses the history and structure of GPCRs, how they interact with G-proteins and secondary messengers like cAMP and IP3 to activate intracellular signaling pathways. These pathways regulate key cellular processes and are targets for drug development to treat diseases. The document also categorizes different classes of GPCRs and summarizes the mechanisms and physiological roles of various secondary messenger systems like cAMP, IP3, and ion channels in signal transduction.
cell communications and cellular signalling systems vishnuvishnu priya
This document provides a seminar report on cell communications and cellular signaling systems. It contains an introduction to cellular communication and signaling, different forms of communication between cells, types of signaling, targets of drug action including receptors, ion channels, enzymes and carriers. It discusses cellular aspects related to excitation, contraction and secretion involving calcium regulation and release mechanisms. Finally, it covers conclusions and references. The document provides a comprehensive overview of the key topics in cellular communication and signaling in 3 pages with figures and content organized under headings.
- There are 4 main types of receptors: ligand-gated ion channels, G-protein coupled receptors, kinase-linked receptors, and nuclear receptors.
- Ligand-gated ion channels directly open ion channels, G-protein receptors signal through G-proteins, kinase receptors signal through phosphorylation, and nuclear receptors regulate gene transcription as transcription factors.
- Receptors recognize a wide range of ligands and allow cells to respond to changes in their internal or external environment through second messenger signaling pathways.
Cell signaling / Signal Transduction / Transmembrane signaling.
It is the process by which cells communicate with their environment and respond to external stimuli.
When a signaling molecule(ligand) binds to its receptor, it alters the shape or activity of the receptor, triggering a change inside of the cell such as alteration in the activity of a gene / cell division. Thus the original Intercellular Signal is converted into an Intracellular Signal that triggers as a response.
Cell signaling involves chemical signals binding to cell surface receptors and activating intracellular signal transduction pathways. There are two main ways signals work: by changing the activity of existing proteins or by changing the amount of proteins in the cell. Common types of signals include hormones, growth factors, and neurotransmitters. Signal transduction involves second messengers such as cAMP and IP3 that activate downstream effector proteins like protein kinases. G-protein coupled receptors are a major class of receptors that activate intracellular signaling pathways.
RECEPTORS AS BIOLOGCAL DRUG TARGETS ppt.pptxosmanshaheen
Receptors are biological molecules that bind to specific ligands or drugs to produce a cellular response. There are several types of receptors including cell surface receptors like G-protein coupled receptors and receptor tyrosine kinases, as well as intracellular receptors. When a ligand binds to a receptor, it causes a conformational change in the receptor that propagates a signal through various pathways to produce an effect in the cell. Agonists mimic endogenous ligands to activate receptors, while antagonists bind receptors but prevent activation. The binding of ligands is influenced by various chemical forces including covalent, electrostatic, and hydrophobic interactions. Receptors are important drug targets, and understanding their functions and binding properties is essential for drug development.
Receptors are proteins located on cells that receive signals from outside the cell and trigger a response. There are four main types of receptor families: ligand gated ion channels, G-protein coupled receptors, tyrosine kinase receptors, and nuclear receptors. Secondary messengers are intracellular molecules that transmit signals from receptors to trigger physiological changes in the cell. Common secondary messengers include cyclic AMP, cyclic GMP, calcium ions, IP3, DAG, and nitric oxide. They activate pathways that lead to processes like proliferation, differentiation, and apoptosis.
This document discusses receptor and signal transduction mechanisms. It begins by defining receptors as proteins that bind hormones, neurotransmitters, and other chemicals with specificity and affinity to produce cellular responses. It then describes the main functions of receptors. The document outlines the major categories of signal transduction mechanisms: ion channel linked, G protein coupled, enzyme linked, JAK-STAT binding, and nuclear receptors. For each category, it provides examples and describes the basic process of signal propagation and cellular response. In summary, it provides an overview of receptor types and the main pathways of signal transduction in cells.
The document discusses different types of receptors and how they function. It describes transmembrane receptors like G protein-coupled receptors and ionotropic receptors. It also discusses intracellular receptors like nuclear receptors and receptor tyrosine kinases. The key concepts covered are how ligands bind to receptors and the downstream cell signaling pathways that are activated, including G proteins, second messengers like cAMP and IP3/DAG, and transcriptional regulation. Receptor properties like affinity, efficacy, desensitization, and regulation are also summarized.
1. The document discusses signal transduction and second messengers. It provides examples of epinephrine, insulin, and epidermal growth factor signaling pathways.
2. Key steps in signal transduction pathways include the release of a primary messenger like a hormone, reception by cell surface receptors, transmission of the signal inside the cell by a second messenger, activation of effector proteins, and termination of the signal.
3. Epinephrine signaling involves G protein coupled receptors that activate adenylate cyclase via G proteins, increasing cyclic AMP and activating protein kinase A. Insulin signaling activates its receptor tyrosine kinase, initiating a phosphorylation cascade. Calcium is also a widespread second messenger that activates proteins like calmodulin
This document provides information about a receptor pharmacology course taught by Professor Dr. Md. Shah Amran at the University of Dhaka. It was prepared by 5 students and contains contents on different types of receptors including ligand gated ion channels, G-protein coupled receptors, enzyme linked receptors, nuclear receptors, and a comparison of receptor types. Receptors are important macromolecules that bind drugs and mediate their effects in the body.
This document provides information about a receptor pharmacology course taught by Professor Dr. Md. Shah Amran at the University of Dhaka. It was prepared by 5 students and contains an introduction to receptors, classifications of different receptor types including ligand gated ion channels, G-protein coupled receptors, enzyme linked receptors, and nuclear receptors. It also discusses receptor-drug interactions, affinity, intrinsic activity, and mechanisms of cell surface and intracellular receptors.
The document discusses various types of signal transduction in cells. It describes how extracellular signals like hormones bind to cell surface receptors and trigger intracellular signaling pathways using second messengers. These pathways involve G proteins and the production of molecules like cyclic AMP and inositol triphosphates to activate enzymes like protein kinase A and C. This leads to changes in gene expression, metabolism and cell behavior in response to extracellular signals.
The document discusses second messenger systems. It describes how second messengers relay signals from cell surface receptors to target molecules inside the cell. Some key points discussed include:
- Earl Sutherland discovered cyclic AMP (cAMP) as the second messenger for epinephrine and won the Nobel Prize for this work.
- Common second messenger systems include those using cAMP, cGMP, phosphatidylinositol, and tyrosine kinases as secondary messengers.
- G proteins act as transducers between receptors and effectors and are important drug targets.
- cAMP and cGMP have several downstream targets including protein kinases that phosphorylate other proteins and regulate various cellular processes.
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2. TYPES OF RECEPTOR
Receptors elicit many different types of cellular effect.
Based on molecular structure and the nature of this linkage (the
transduction mechanism),
we can distinguish four receptor types, or superfamilies .
Type 1: ligand-gated ion channels (also known as ionotropic
receptors).
These are membrane proteins with a similar structure to other ion
channels, and incorporate a ligand-binding (receptor) site, usually
in the extracellular domain.
Typically, these are the receptors on which fast neurotransmitters
act.
Examples include the nicotinic acetylcholine receptor (nAChR;
GABAA receptor; and glutamate receptors of the NMDA, AMPA and
kainate types.
3. Molecular structure of TYPE 1 RECEPTOR:
The nicotinic acetylcholine receptor, the first to be
cloned.
It is assembled from 4 different types of subunit, termed
α, β, γ and δ.
The four subunits show marked sequence homology, and
analysis of the hydrophobicity profile, which
determines which sections of the chain are likely to
form membrane-spanning α helices, suggests that they
are inserted into the membrane .
The pentameric structure (α2, β, γ, δ) possesses two
acetylcholine binding sites, each lying at the interface
between one of the two α subunits and its neighbour.
4. The two acetylcholine-binding sites lie on the
extracellular parts of the two α subunits.
One of the transmembrane helices (M2) from each of
the five subunits forms the lining of the ion channel.
The five M2 helices that form the pore are sharply
Linked inwards halfway through the membrane,
forming a constriction.
When acetylcholine molecules bind, the α subunits
twist, causing the kinked M2 segments to swivel out
of the way, thus opening the channel .
5. Structure of the nicotinic acetylcholine receptor (a typical ligand-gated ion channel) in
side view (left) and plan view (right).
The five receptor subunits (α2, β, γ, δ) form a cluster surrounding a central
transmembrane pore, the lining of which is formed by the M2 helical segments of each
subunit.
6. Receptors of this type control the fastest synaptic
events in the nervous system, in which a
neurotransmitter acts on the postsynaptic
membrane of a nerve or muscle cell and transiently
increases its permeability to particular ions.
Most excitatory neurotransmitters, such as
acetylcholine at the neuromuscular junction or
glutamate in the central nervous system, cause an
increase in Na+ and K+s permeability.
This results in a net inward current carried mainly by
Na+, which depolarises the cell and increases the
probability that it will generate an action potential.
7. The action of the transmitter reaches a peak in a
fraction of a millisecond, and usually decays within
a few milliseconds.
In contrast to other receptor families, no intermediate
biochemical steps are involved in the transduction
process.
8.
9. ACTION POTENTIAL:
Action potentials are nerve signals. Neurons generate
and conduct these signals along their processes in
order to transmit them to the target tissues.
Upon stimulation, they will either be stimulated,
inhibited, or modulated in some way. structure and
all the types of the neurons with the following study
unit.
An action potential has several phases;
hypopolarization, depolarization, overshoot,
repolarization and hyperpolarization.
10. DEPOLARISATION:
The threshold potential opens voltage-gated sodium channels
and causes a large influx of sodium ions. This phase is called
the depolarization.
During depolarization, the inside of the cell becomes more and
more electropositive.
REPOLARISATION:
After the overshoot, the sodium permeability suddenly
decreases due to the closing of its channels.
The overshoot value of the cell potential opens voltage-gated
potassium channels, which causes a large potassium efflux,
decreasing the cell’s electropositivity.
This phase is the repolarization phase, whose purpose is to
restore the resting membrane potential.
11. Repolarization always leads first to hyperpolarization,
a state in which the membrane potential is more
negative than the default membrane potential.
But soon after that, the membrane establishes again
the values of membrane potential.
12. Type 2: G-protein-coupled receptors (GPCRs).
These are also known as metabotropic receptors or 7-
transmembrane-spanning (heptahelical) receptors.
They are membrane receptors that are coupled to
intracellular effector systems via a G-protein .
They constitute the largest family,and include
receptors for many hormones and slow
transmitters, for example the muscarinic
acetylcholine receptor (mAChR; , adrenergic
receptorsand chemokine receptors
13. MOLECULAR STRUCTURE OF G-PCR
G-protein-coupled receptors consist of a single
polypeptide chain of up to 1100 residues.
Their characteristic structure comprises seven
transmembrane α helices, similar to those of the ion
channels , with an extracellular N-terminal domain of
varying length, and an intracellular C-terminal domain.
GPCRs are divided into three distinct families.
They share the same seven-helix (heptahelical) structure,
but differ in other respects, principally in the length of
the extracellular N terminus and the location of the
agonist binding domain.
14. Family A is by far the largest, comprising most
monoamine, neuropeptide and chemokine
receptors.
Family B includes receptors for some other peptides,
such as calcitonin and glucagon.
Family C is the smallest, its main members being the
metabotropic glutamate and GABA receptors and
the Ca2+-sensing receptors.
15.
16. The function of the G-protein. The G-protein consists of three subunits (α, β, γ), which are anchored to the membrane
through attached lipid residues. Coupling of the α subunit to an agonist-occupied receptor causes the bound GDP to
exchange with intracellular GTP; the α-GTP complex then dissociates from the receptor and from the βγ complex, and
interacts with a target protein (target 1, which may be an enzyme, such as adenylate cyclase, or an ion channel).
The βγ complex may also activate a target protein (target 2).
The GTPase activity of the α subunit is increased when the target protein is bound, leading to hydrolysis of the bound GTP
to GDP, whereupon the α subunit reunites with βγ
17. G-Protein subunits Main effectors
Gαs Many amine and other receptors
(e.g. catecholamines, histamine,
serotonin)
Stimulates adenylyl cyclase, causing increased
cAMP formation.
Gαi As for Gαs, also opioid,
cannabinoid receptors
Inhibits adenylyl cyclase, decreasing cAMP
formation.
Gαo As for Gαs, also opioid,cannabinoid
receptors
Limited effects of αsubunit (effects mainly due to
βγsubunits)
Gαq Amine, peptide and prostanoid
receptors
Activates phospholipase C, increasing production of
second messengers inositol trisphosphate and
diacylglycerol
Gβγ subunits All GPCRs As for Gα subunits (see above). Also:
• activate potassium channels
• inhibit voltage-gated calcium channels
• activate GPCR kinases (p. 40)
• activate mitogen-activated protein kinase cascade
18. Transduction pathways in GPCR’s
There are 3major effector pathways through which G-
protein coupled receptors function. They are:
a)Adenylcyclase:cAMP pathway
b)Phospholipase C: IP3-DAG Pathway
c)Channel Regulation
19. a)Adenylcyclase:cAMP pathway
cAMP is a nucleotide synthesised within the cell from ATP by the action of a
membrane-bound enzyme, adenylyl cyclase.
It is produced continuously and inactivated by hydrolysis to 5´-AMP, by the action of a
family of enzymes known as phosphodiesterases (PDEs).
Many different drugs, hormones and neurotransmitters act on GPCRs and produce their
effects by increasing or decreasing the catalytic activity of adenylyl cyclase, thus
raising or lowering the concentration of cAMP within the cell.
There are several different molecular isoforms of the enzyme, some of which respond
selectively to Gαs or Gαi
20.
21. b) Phospholipase C: IP3-DAG Pathway
The phosphoinositide system, an important intracellular second messenger system, was
first discovered in the 1950s by Hokin and Hokin.
Activation of PLc hydrolyses the membrane phospholipid phosphatidylionositol 4.5-
bihosphate (PIP2),to generate the second messengers …….IP3 & DAG.
IP3 mobilises Ca+2 from intracellular depots & DAG enhances proten knase C
activation by Ca+2.
Ca+2 …Third messenger is a highly versatile regulator acting through CAM
(Calmodulin),PKc & other effectors.
22.
23. c)Channel Regulation
G-protein-coupled receptors can control ion channel function directly by mechanisms
that do not involve second messengers such as cAMP or inositol phosphates. This
was first shown for cardiac muscle, but it now appears that direct G-protein-channel
interaction may be quite general .
The activated G-proteins can also open or close ionic channels specific for
Ca+2,K+/Na+2 & bring about Hyperpolarisation/ Depolarisation/ changes in
intracellular Ca+2 .
Eg: Gs opens Ca+2 channels in myocardium & skeletal muscles.
Gi & Go opens K+ channels in heart & smooth muscles as well as close Neuronal
Ca+2 channels.
24. These membrane receptors are quite different in structure and function
from either the ligand-gated channels or the GPCRs.
They play a major role in controlling cell division, growth,
differentiation, inflammation, tissue repair, apoptosis and immune
responses.
The main types are as follows:
Receptor tyrosine kinases (RTKs). These receptors have the basic
structure incorporating a tyrosine kinase moiety in the intracellular
region.
They include receptors for many growth factors, such as epidermal
growth factor and nerve growth factor, and also the group of Toll-like
receptors that recognise bacterial lipopolysaccarides and play an
important role in the body's reaction to infection …
The insulin receptor also belongs to the RTK class, although it has a
more complex dimeric structure.
Type 3: Enzymatic Receptors
25. Serine/threonine kinases:
This smaller class is similar in structure to RTKs but phosphorylate
serine and/or threonine residues rather than tyrosine.
The main example is the receptor for transforming growth factor (TGF).
Cytokine receptors:
These receptors lack intrinsic enzyme activity.
When occupied, they associate with, and activate, a cytosolic tyrosine
kinase, such as Jak (the Janus kinase) or other kinases.
Ligands for these receptors include cytokines such as interferons and
colony-stimulating factors(CSF) involved in immunological
responses.
Guanylyl cyclase-linked receptors:
These are similar in structure to RTKs, but the enzymic moiety is
guanylyl cyclase and they exert their effects by stimulating cGMP
formation.
The main example is the receptor for ANF .
26. Two well-defined signal transduction pathways are
summarised in The Ras/Raf pathway mediates the
effect of many growth factors and mitogens.
Ras, which is a proto-oncogene product, functions like a
G-protein, and conveys the signal (by GDP/GTP
exchange) from the SH2 domain protein, Grb, which is
phosphorylated by the RTK.
Activation of Ras in turn activates Raf, which is the first of
a sequence of three serine/threonine kinases, each of
which phosphorylates, and activates, the next in line.
The last of these, mitogen-activated protein (MAP)
kinase, phosphorylates one or more transcription
factors that initiate gene expression, resulting in a
variety of cellular responses, including cell division.
27. This three-tiered MAP kinase cascade forms part of
many intracellular signalling pathways involved in a
wide variety of disease processes, including
malignancy, inflammation, neurodegeneration,
atherosclerosis and much else.
The kinases form a large family, with different
subtypes serving specific roles. They are thought to
represent an important target for future
therapeutic drugs.
Many cancers are associated with mutations in the
genes coding for proteins involved in this cascade,
leading to activation of the cascade in the absence
of the growth factor signal .
28. A second pathway, the Jak/Stat pathway is involved in
responses to many cytokines.
Dimerisation of these receptors occurs when the cytokine
binds, and this attracts a cytosolic tyrosine kinase unit
(Jak) to associate with, and phosphorylate, the receptor
dimer.
Jaks belong to a family of proteins, different members
having specificity for different cytokine receptors.
Among the targets for phosphorylation by Jak are a
family of transcription factors (Stats).
These are SH2 domain proteins that bind to the
phosphotyrosine groups on the receptor-Jak complex,
and are themselves phosphorylated.
Thus activated, Stat migrates to the nucleus and activates
gene expression
31. TYPE 4: NUCLEAR RECEPTORS
The fourth type of receptors we will consider belong
to the nuclear receptor family.
By the 1980s, it was clear that receptors for steroid
hormones such as oestrogen and the
glucocorticoids were present in the cytoplasm of
cells and translocated into the nucleus after binding
with their steroid partner.
Other hormones, such as the thyroid hormone T3 and
the fat-soluble vitamins D and A (retinoic acid) and
their derivatives that regulate growth and
development, were found to act in a similar fashion.
32. Today, it is convenient to regard the entire nuclear
receptor family as ligand-activated transcription
factors that transduce signals by modifying gene
transcription.
The nuclear receptor superfamily consist of two main
classes-together with a third that shares some of
the characteristics of both.
Class I consists largely of receptors for the steroid
hormones, including the glucocorticoid and
mineralocorticoid receptors (GR and MR,
respectively), as well as the oestrogen,
progesterone and androgen receptors (ER, PR, and
AR, respectively).
33. Class I receptors generally recognise hormones that act in
a negative feedback fashion to control biological
events.
Class II nuclear receptors function in a slightly different
way. Their ligands are generally lipids already present to
some extent within the cell.
This group includes the peroxisome proliferator-activated
receptor (PPAR) that recognises fatty acids;
The liver oxysterol (LXR) receptor that recognises and acts
as a cholesterol sensor,
The farnesoid (bile acid) receptor (FXR), a xenobiotic
receptor (SXR; in rodents the PXR) that recognises a
great many foreign substances, including therapeutic
drugs, and
The constitutive androstane receptor (CAR), which not
only recognises the steroid androstane but also some
drugs such as phenobarbital.