Membrane receptor - AbsoluteAstronomy.com

Cell surface receptors (membrane receptors, transmembrane receptors) are specialized integral membrane protein

Integral membrane protein

An integral membrane protein is a protein molecule that is permanently attached to the biological membrane. Proteins that cross the membrane are surrounded by "annular" lipids, which are defined as lipids that are in direct contact with a membrane protein...

s that take part in communication between the cell and the outside world. Extracellular signaling molecule

Signaling molecule

A signaling molecule is a chemical involved in transmitting information between cells. Such molecules are released from the cell sending the signal, cross over the gap between cells by diffusion, and interact with specific receptors in another cell, triggering a response in that cell by activating...

s (usually hormone

Hormone

A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

s, neurotransmitters, cytokines, growth factors or cell recognition molecules

Cell adhesion molecule

Cell Adhesion Molecules are proteins located on the cell surface involved with the binding with other cells or with the extracellular matrix in the process called cell adhesion....

) attach to the receptor

Receptor (biochemistry)

In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

, triggering changes in the function of the cell

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

. This process is called signal transduction

Signal transduction

Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...

: The binding initiates a chemical change on the intracellular

Intracellular

Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...

side of the membrane. In this way the receptors play a unique and important role in cellular communications and signal transduction.

Structure and mechanism

Many transmembrane receptors are composed of two or more protein subunit

Protein subunit

In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles with other protein molecules to form a protein complex: a multimeric or oligomeric protein. Many naturally occurring proteins and enzymes are multimeric...

s which operate collectively and may dissociate when ligand

Ligand (biochemistry)

In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. In a narrower sense, it is a signal triggering molecule, binding to a site on a target protein.The binding occurs by intermolecular forces, such as ionic bonds, hydrogen...

s bind, fall off, or at another stage of their "activation" cycles. They are often classified based on their molecular structure

Tertiary structure

In biochemistry and molecular biology, the tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates.-Relationship to primary structure:...

, or because the structure is unknown in any detail for all but a few receptors, based on their hypothesized (and sometimes experimentally verified) membrane topology

Membrane topology

In biochemistry, the membrane topology of an transmembrane protein describes which portions of the amino-acid sequence of the protein lie within the plane of the surrounding lipid bilayer and which portions protrude into the watery environment on either side...

. The polypeptide chains

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

of the simplest are predicted to cross the lipid bilayer

Lipid bilayer

The lipid bilayer is a thin membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around cells. The cell membrane of almost all living organisms and many viruses are made of a lipid bilayer, as are the membranes surrounding the cell nucleus...

only once, while others cross as many as seven times (for example, the so-called G-protein coupled receptor

G protein-coupled receptor

G protein-coupled receptors , also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors , comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal...

s).

There are various kinds, such as glycoprotein

Glycoprotein

Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...

and lipoprotein

Lipoprotein

A lipoprotein is a biochemical assembly that contains both proteins and lipids water-bound to the proteins. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are lipoproteins...

. Hundreds of different receptors are known and many more are yet to be discovered. Almost all known membrane receptors are transmembrane protein

Transmembrane protein

A transmembrane protein is a protein that goes from one side of a membrane through to the other side of the membrane. Many TPs function as gateways or "loading docks" to deny or permit the transport of specific substances across the biological membrane, to get into the cell, or out of the cell as...

s. A certain cell membrane can have several membrane receptors with various amounts on its surface. A certain receptor may also exist at varying concentrations on different membrane surfaces, depending on the membrane and cell function. Since receptors usually form “clusters” on the membrane surface, the distribution of receptors on membrane surface is mostly heterogeneous.

Domains

Like any integral membrane protein, a transmembrane receptor may be subdivided into three parts or domains.

Extracellular domain

The extracellular domain is the part of the receptor that sticks out of the membrane on the outside of the cell or organelle

Organelle

In cell biology, an organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid bilayer....

. If the polypeptide chain of the receptor crosses the bilayer several times, the external domain can comprise several "loops" sticking out of the membrane. By definition, a receptor's main function is to recognize and respond to a specific ligand, for example, a neurotransmitter

Neurotransmitter

Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...

or hormone

Hormone

(although certain receptors respond also to changes in transmembrane potential), and in many receptors these ligands bind to the extracellular domain.

Transmembrane domain

In the majority of receptors for which structural evidence exists, transmembrane alpha helices

Transmembrane helix

Transmembrane domain usually denotes a single transmembrane alpha helix of a transmembrane protein. It is called a "domain" because an alpha-helix in a membrane can fold independently from the rest of the protein, similar to domains of water-soluble proteins...

make up most of the transmembrane domain. In certain receptors, such as the nicotinic acetylcholine receptor

Acetylcholine receptor

An acetylcholine receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.-Classification:...

, the transmembrane domain forms a protein-lined pore through the membrane, or ion channel

Ion channel

Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of cells by allowing the flow of ions down their electrochemical gradient. They are present in the membranes that surround all biological cells...

. Upon activation of an extracellular domain by binding of the appropriate ligand, the pore becomes accessible to ions, which then pass through. In other receptors, the transmembrane domains are presumed to undergo a conformational change upon binding, which exerts an effect intracellularly. In some receptors, such as members of the 7TM superfamily

G protein-coupled receptor

, the transmembrane domain may contain the ligand binding pocket (evidence for this and for much of what else is known about this class of receptors is based in part on studies of bacteriorhodopsin

Bacteriorhodopsin

Bacteriorhodopsin is a protein used by Archaea, the most notable one being Halobacteria. It acts as a proton pump; that is, it captures light energy and uses it to move protons across the membrane out of the cell...

, the detailed structure of which has been determined by crystallography

Crystallography

Crystallography is the experimental science of the arrangement of atoms in solids. The word "crystallography" derives from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and grapho = write.Before the development of...

Intracellular domain

The intracellular (or cytoplasm

Cytoplasm

The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

ic) domain of the receptor interacts with the interior of the cell or organelle, relaying the signal. There are two fundamentally different ways for this interaction:

The intracellular domain communicates via specific protein-protein-interactions with effector proteins, which in turn send the signal along a signal chain to its destination.
With enzyme-linked receptor
Enzyme-linked receptor
An enzyme-linked receptor is a transmembrane receptor, where the binding of an extracellular ligand causes enzymatic activity on the intracellular side.These are found in all living species....

s, the intracellular domain has enzymatic activity
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

. Often, this is a tyrosine kinase
Tyrosine kinase
A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to a protein in a cell. It functions as an "on" or "off" switch in many cellular functions....

activity. The enzymatic activity can also be located on an enzyme associated with the intracellular domain.

Signal transduction

Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...

processes through membrane receptors involve the External Reactions, in which the ligand binds to a membrane receptor, and the Internal Reactions, in which intracellular response is triggered.

Signal transduction through membrane receptors usually requires four characters:

Extracellular signal molecule: an extracellular signal molecule is produced by one cell and is capable of traveling to neighboring cells, or to cells that may be far away.
Receptor protein: the cells in an organism must have cell surface receptor proteins that bind to the signal molecule and communicate its presence inward into the cell.
Intracellular signaling proteins: these distribute the signal to the appropriate parts of the cell. The binding of the signal molecule to the receptor protein will activate intracellular signaling proteins that initiate a signaling cascade (a series of intracellular signaling molecules that act sequentially).
Target proteins: the conformations or other properties of the target proteins are altered when a signaling pathway is active and changes the behavior of the cell.

Based on structural and functional similarities, membrane receptors are mainly divided into 3 classes: The ion channel-linked receptor

Ligand-gated ion channel

Ligand-gated ion channels are one type of ionotropic receptor or channel-linked receptor. They are a group of transmembrane ion channels that are opened or closed in response to the binding of a chemical messenger , such as a neurotransmitter.The binding site of endogenous ligands on LGICs...

; The enzyme-linked receptor

Enzyme-linked receptor

An enzyme-linked receptor is a transmembrane receptor, where the binding of an extracellular ligand causes enzymatic activity on the intracellular side.These are found in all living species....

and G protein-coupled receptor

G protein-coupled receptor

Ion channel linked receptors
Ion channel linked receptors
Ion channel linked receptors are cell membrane bound receptors. They act through synaptic signaling on electrically excitable cells. The ion channels opening and closing is controlled by neurotransmitters....

are ion-channels (including cation-channels and anion-channels) themselves and constitute a large family of multipass transmembrane proteins. They are involved in rapid signaling events most generally found in electrically excitable cells such as neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

s and are also called ligand-gated ion channel
Ligand-gated ion channel
Ligand-gated ion channels are one type of ionotropic receptor or channel-linked receptor. They are a group of transmembrane ion channels that are opened or closed in response to the binding of a chemical messenger , such as a neurotransmitter.The binding site of endogenous ligands on LGICs...

s. Opening and closing of Ion channels are controlled by neurotransmitters.

Enzyme-linked receptor
Enzyme-linked receptor
An enzyme-linked receptor is a transmembrane receptor, where the binding of an extracellular ligand causes enzymatic activity on the intracellular side.These are found in all living species....

s are either enzymes themselves, or are directly associated with the enzymes that they activate. These are usually single-pass transmembrane receptors, with the enzymatic portion of the receptor being intracellular. The majority of enzyme-lined receptors are protein kinases, or associate with protein kinases.

G protein-coupled receptor
G protein-coupled receptor
G protein-coupled receptors , also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors , comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal...

s are integral membrane proteins that possess seven membrane-spanning domains or transmembrane helices. These receptors activate a G protein
G protein
G proteins are a family of proteins involved in transmitting chemical signals outside the cell, and causing changes inside the cell. They communicate signals from many hormones, neurotransmitters, and other signaling factors. G protein-coupled receptors are transmembrane receptors...

ligand binding. G-protein is a trimeric protein. The 3 subunits are called α、β and γ. The α subunit can bind with guanosine diphosphate
Guanosine diphosphate
Guanosine diphosphate, abbreviated GDP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside guanosine. GDP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase guanine....

, GDP. This causes phosphorylation
Phosphorylation
Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....

of the GDP to guanosine triphosphate
Guanosine triphosphate
Guanosine-5'-triphosphate is a purine nucleoside triphosphate. It can act as a substrate for the synthesis of RNA during the transcription process...

, GTP, and activates the α subunit, which then dissociates from the β and γ subunits. The activated α subunit can further affect intracellular signaling proteins or target functional proteins directly.

Ion channel-linked receptor

In the signal transduction event in a neuron, the neurotransmitter binds with the receptor and alters the conformation of the protein, which opens the ion-channel, allowing extracellular ions go into the cell. The ion permeability of the plasma membrane is altered, and this will instantaneously convert the extracellular chemical signal into intracellular electric signal, which will alter the excitability of the cell.

Acetylcholine

Acetylcholine

The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...

receptor is a kind of cation-channel linked receptor. The protein consists of 4 subunits: α, β, γ, and δ subunits. There are two α subunits, containing one acetylcholine binding site each. This receptor can exist in three different conformations. The unoccupied-closed state is the protein at its original conformation. After two molecules of acetylcholine bind simultaneously to the binding sites on α subunits, the conformation of the receptor is altered and the gate is opened, allowing for the penetration of many ions and small molecules. However, this occupied-open state can only last for a very short period of time and then the gate is closed again, forming the occupied-closed state. The two molecules of acetylcholine will quickly dissociate from the receptor and the receptor will returns to its unoccupied-closed state and is ready for next transduction cycle again.

Enzyme-linked receptors

As of 2009, there are 6 known types of enzyme-linked receptors: Receptor tyrosine kinase

Tyrosine kinase

A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to a protein in a cell. It functions as an "on" or "off" switch in many cellular functions....

s; Tyrosine kinase associated receptors; Receptor-like tyrosine phosphatases

Protein tyrosine phosphatase

Protein tyrosine phosphatases are a group of enzymes that remove phosphate groups from phosphorylated tyrosine residues on proteins. Protein tyrosine phosphorylation is a common post-translational modification that can create novel recognition motifs for protein interactions and cellular...

; Receptor serine

Serine

Serine is an amino acid with the formula HO2CCHCH2OH. It is one of the proteinogenic amino acids. By virtue of the hydroxyl group, serine is classified as a polar amino acid.-Occurrence and biosynthesis:...

/threonine kinases; Receptor Guanylyl cyclases

Guanylate cyclase

-Reaction:Guanylate cyclase catalyzes the reaction of guanosine triphosphate to 3',5'-cyclic guanosine monophosphate and pyrophosphate:-Types:...

and Histidine kinase

Histidine kinase

Histidine Kinases are multifunctional, typically transmembrane, proteins of the transferase class that play a role in signal transduction across the cellular membrane. The vast majority of HKs are homodimers that exhibit autokinase, phosphotransfer, and phosphatase activity. HKs can act as...

associated receptors. Receptor tyrosine kinases is the one kind with the largest population and most widely application. The majority of these molecules are receptors for growth factor

Growth factor

A growth factor is a naturally occurring substance capable of stimulating cellular growth, proliferation and cellular differentiation. Usually it is a protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes....

s and hormones like epidermal growth factor

Epidermal growth factor

Epidermal growth factor or EGF is a growth factor that plays an important role in the regulation of cell growth, proliferation, and differentiation by binding to its receptor EGFR...

(EGF), platelet derived growth factor

Platelet-derived growth factor

In molecular biology, platelet-derived growth factor is one of the numerous growth factors, or proteins that regulate cell growth and division. In particular, it plays a significant role in blood vessel formation , the growth of blood vessels from already-existing blood vessel tissue. Uncontrolled...

(PDGF), fibroblast growth factor (FGF), hepatocyte growth factor (HGF), insulin, nerve growth factor (NGF) etc.

Most of these receptors will dimerize after binding with their ligands in order to activate further signal transductions. For example, after the epidermal growth factor (EGF)

Epidermal growth factor

Epidermal growth factor or EGF is a growth factor that plays an important role in the regulation of cell growth, proliferation, and differentiation by binding to its receptor EGFR...

receptor binds with its ligand EGF, two receptors dimerize and then undergo phosphorylation

Phosphorylation

Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....

of the tyrosine

Tyrosine

Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...

residues in the enzyme portion of each receptor molecule, which will activate the tyrosine protein kinase

Tyrosine kinase

A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to a protein in a cell. It functions as an "on" or "off" switch in many cellular functions....

and analyze further intracellular reactions.

G protein-linked receptors

G protein-coupled receptors comprise a large protein

Protein

family transmembrane receptors. They are found only in eukaryote

Eukaryote

A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear...

s. The ligands

Ligand (biochemistry)

that bind and activate these receptors include light-sensitive compounds, odor

Odor

An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...

s, pheromone

Pheromone

A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...

s, hormone

Hormone

s, and neurotransmitter

Neurotransmitter

s, and vary in size from small molecules to peptide

Peptide

Peptides are short polymers of amino acid monomers linked by peptide bonds. They are distinguished from proteins on the basis of size, typically containing less than 50 monomer units. The shortest peptides are dipeptides, consisting of two amino acids joined by a single peptide bond...

s to large protein

Protein

s. G protein-coupled receptors are involved in many diseases, and are also the target of around half of all modern medicinal drugs.

There are two principal signal transduction pathways involving the G-protein coupled receptors: cAMP

Cyclic adenosine monophosphate

Cyclic adenosine monophosphate is a second messenger important in many biological processes...

signal pathway and Phosphatidylinositol

Phosphatidylinositol

Phosphatidylinositol is a negatively charged phospholipid and a minor component in the cytosolic side of eukaryotic cell membranes....

signal pathway. Both activate a G protein

G protein

G proteins are a family of proteins involved in transmitting chemical signals outside the cell, and causing changes inside the cell. They communicate signals from many hormones, neurotransmitters, and other signaling factors. G protein-coupled receptors are transmembrane receptors...

ligand binding. G-protein is a trimeric protein. The 3 subunits are called α、β and γ. The α subunit can bind with guanosine diphosphate

Guanosine diphosphate

Guanosine diphosphate, abbreviated GDP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside guanosine. GDP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase guanine....

, GDP. This causes phosphorylation

Phosphorylation

Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....

of the GDP to guanosine triphosphate

Guanosine triphosphate

Guanosine-5'-triphosphate is a purine nucleoside triphosphate. It can act as a substrate for the synthesis of RNA during the transcription process...

, GTP, and activates the α subunit, which then dissociates from the β and γ subunits. The activated α subunit can further affect intracellular signaling proteins or target functional proteins directly.

Membrane receptor-related disease

If the membrane receptors are altered directly or deficient for some reason, the signal transduction can be hindered and cause diseases. Some diseases are caused by membrane receptor function disorder due to deficiency or disorder of the receptor induced by the change in the genes that encode the receptor protein. Scientists recently have found that the membrane receptor TM4SF5

TM4SF5

Transmembrane 4 L6 family member 5 is a protein that in humans is encoded by the TM4SF5 gene.-Further reading:...

has something to do with the migration ability of hepatic cells and hepatoma. and that the cortical NMDA receptor properties and membrane fluidity are altered in Alzheimer's disease. Also, when the cell is infected by nonenveloped virus, the virus first binds with certain membrane receptors and then somehow the virus or some subviral component ends up on the cytoplasmic side of a cellular membrane, the plasma membrane for some viruses or the membrane of an endosomal vesicle for others. In the case of poliovirus

Poliovirus

Poliovirus, the causative agent of poliomyelitis, is a human enterovirus and member of the family of Picornaviridae.Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA genome that is about 7500 nucleotides long. The viral particle is...

, it is known that interactions with receptors in vitro will lead to conformational rearrangements of the virion that result in the release of one of the virion proteins, called VP4.The N terminal of VP4 is myristylated and thus hydrophobic【myristic acid

Myristic acid

Myristic acid, also called tetradecanoic acid, is a common saturated fatty acid with the molecular formula CH312COOH. A myristate is a salt or ester of myristic acid....

=CH₃(CH₂)₁₂COOH】. It is proposed that the conformational changes induced by receptor binding result in the insertion of the myristic acid on VP4 into the cell membrane and the formation of a channel through which the RNA can enter the cell.

Structure-based drug design

As methods such as X-ray crystallography

X-ray crystallography

X-ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X-rays strikes a crystal and causes the beam of light to spread into many specific directions. From the angles and intensities of these diffracted beams, a crystallographer can produce a...

and NMR spectroscopy

NMR spectroscopy

Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei to determine physical and chemical properties of atoms or the molecules in which they are contained...

develop, the amount of information about 3D structures of biomolecular targets has increased dramatically, as well as the structural dynamic and electronic information about the ligands. This stimulates rapid development of structure-based drug design. Some of these new drugs target membrane receptors. Current methods for structure-based drug design can be divided roughly into two categories. The first category is about “finding” ligands for a given receptor. This is usually referred to as database searching. In this case, a large number of potential ligand molecules are screened to find those fitting the binding pocket of the receptor. This method is usually referred to as ligand-based drug design. The key advantage of database searching is that it saves synthetic effort to obtain new lead compounds. Another category of structure-based drug design methods is about “building” ligands, which is usually referred to as receptor-based drug design. In this case, ligand molecules are built up within the constraints of the binding pocket by assembling small pieces in a stepwise manner. These pieces can be either atoms or fragments. The key advantage of such a method is that novel structures, not contained in any database, can be suggested.

External links

IUPHAR GPCR Database

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Structure and mechanism

Domains

Extracellular domain

Transmembrane domain

Intracellular domain

Signal transduction

Ion channel-linked receptor

Enzyme-linked receptors

G protein-linked receptors

Membrane receptor-related disease

Structure-based drug design

See also

Other examples

External links