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Receptor (biochemistry)
 
 
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In biochemistry
Biochemistry

Biochemistry is the study of the chemistry processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules....
, a receptor is a protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
 molecule, embedded in either the plasma membrane or cytoplasm
Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
 of a cell, to which a mobile signaling (or "signal") molecule may attach. A molecule which binds to a receptor is called a "ligand
Ligand (biochemistry)

In biochemistry, a ligand is a Chemical substance that is able to bind to and form a Complex with a biomolecule to serve a biological purpose....
," and may be a peptide (such as a neurotransmitter
Neurotransmitter

Neurotransmitters are chemistry which relay, amplify and modulate signals between a neuron and another cell . Neurotransmitters are packaged into vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of...
), a hormone
Hormone

Hormones are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism....
, a pharmaceutical drug, or a toxin, and when such binding occurs, the receptor goes into a conformational change which ordinarily initiates a cellular response.






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In biochemistry
Biochemistry

Biochemistry is the study of the chemistry processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules....
, a receptor is a protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
 molecule, embedded in either the plasma membrane or cytoplasm
Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
 of a cell, to which a mobile signaling (or "signal") molecule may attach. A molecule which binds to a receptor is called a "ligand
Ligand (biochemistry)

In biochemistry, a ligand is a Chemical substance that is able to bind to and form a Complex with a biomolecule to serve a biological purpose....
," and may be a peptide (such as a neurotransmitter
Neurotransmitter

Neurotransmitters are chemistry which relay, amplify and modulate signals between a neuron and another cell . Neurotransmitters are packaged into vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of...
), a hormone
Hormone

Hormones are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism....
, a pharmaceutical drug, or a toxin, and when such binding occurs, the receptor goes into a conformational change which ordinarily initiates a cellular response. However, some ligands merely block receptors without inducing any response (e.g. antagonists). Ligand-induced changes in receptors result in physiological changes which constitute the biological activity of the ligands.

Overview

The shapes and actions of receptors are studied by 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 scatters into many different directions....
 and computer modelling, which have advanced the understanding of drug action
Drug action

The action of drugs on the human body is called pharmacodynamics, and what the body does with the drug is called pharmacokinetics. The drugs that enter the human tend to stimulate certain receptors, ion channels, act on enzymes or transporter proteins....
 at the binding sites of receptors. Depending on their functions and ligands
Ligand (biochemistry)

In biochemistry, a ligand is a Chemical substance that is able to bind to and form a Complex with a biomolecule to serve a biological purpose....
, several types of receptors may be identified:
  • Some receptor proteins are peripheral membrane protein
    Peripheral membrane protein

    Peripheral membrane proteins are proteins that adhere only temporarily to the biological membrane with which they are associated. These molecules attach to integral membrane proteins, or penetrate the peripheral regions of the lipid bilayer....
    s.
  • Many hormone
    Hormone receptor

    A hormone receptor is a receptor protein on the surface of a cell or in its interior that binds to a specific hormone. The hormone causes many changes to take place in the cell....
     and neurotransmitter receptor
    Neurotransmitter receptor

    A neurotransmitter receptor is a receptor protein on the surface of a Cell that binds to a specific ligand, or receptors on the surface of the postsynaptic cell, such as a neurotransmitter, receptor antagonist, biogenic amines, etc....
    s are transmembrane proteins
    Transmembrane receptor

    Transmembrane receptors are integral membrane proteins, which reside and operate typically within a cell's plasma membrane, but also in the biological membrane of some subcellular compartments and organelles....
    : transmembrane receptors are embedded in the phospholipid bilayer of cell membrane
    Cell membrane

    The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
    s, that allow the activation of signal transduction
    Signal transduction

    In biology, 'signal transduction' refers to any process by which a cell converts one kind of signal or stimulus into another. Most processes of signal transduction involve ordered sequences of biochemistry chemical reaction inside the cell, which are carried out by enzymes, activated by Second messenger systems, resulting in a signal tran...
     pathways in response to the activation by the binding molecule, or ligand
    Ligand (biochemistry)

    In biochemistry, a ligand is a Chemical substance that is able to bind to and form a Complex with a biomolecule to serve a biological purpose....
    .
    • Metabotropic receptor
      Metabotropic receptor

      Metabotropic receptor is a subtype of membrane receptors at the surface or in vesicles of eukaryotic cells.In the nervous system, based on their structural and functional characteristics, neurotransmitter receptor can be classified into two broad categories: metabotropic and ionotropic receptors....
      s are coupled to G protein
      G protein

      G proteins, short for guanine nucleotide-binding proteins, are a family of proteins involved in second messenger cascades.G proteins are so called because they function as "molecular switches," alternating between an inactive guanosine diphosphate and active guanosine triphosphate bound state, ultimately going on to regulate down...
      s and affect the cell indirectly through enzyme
      Enzyme

      Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
      s which control ion channel
      Ion channel

      Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of all living cell s by allowing the flow of ions down their electrochemical gradient....
      s.
    • Ionotropic receptors contain a central pore which functions as a ligand-gated ion channel.
  • Another major class of receptors are 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 "....
     proteins such as those for steroid
    Steroid

    A steroid is a terpenoid lipid characterized by a carbon skeleton with four fused rings, generally arranged in a 6-6-6-5 fashion.Steroids vary by the functional groups attached to these rings and the oxidation state of the rings....
     and intracrine
    Intracrine

    Intracrine refers to a hormone that acts inside a cell . Steroid hormones act through cell receptor and are thus considered as intracrines. In contrast, peptide or protein hormones generally act as endocrines, autocrines or paracrines by binding to their receptors present on the cell surface....
     peptide hormone
    Peptide hormone

    Peptide hormones are a class of peptide that are secreted into the blood stream and have endocrine functions in living animals. Peptide hormones are increasingly being identified in plants with important roles in cell-to-cell communication and plant defence....
     receptors. These receptors often can enter the cell nucleus
    Cell nucleus

    In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
     and modulate gene expression
    Gene expression

    Gene expression is the process by which inheritable information from a gene, such as the DNA sequence, is made into a functional gene product, such as protein or RNA....
     in response to the activation by the ligand.


Binding and activation

Ligand binding is an equilibrium
Chemical equilibrium

In a chemical process, chemical equilibrium is the state in which the Activity or concentrations of the reactants and products have no net change over time....
 process. Ligands bind to receptors and dissociate from them according to the law of mass action.

(the brackets stand for concentrations)


One measure of how well a molecule fits a receptor is the binding affinity, which is inversely related to the dissociation constant
Dissociation constant

In chemistry and biochemistry, a dissociation constant is a specific type of equilibrium constant that measures the propensity of a larger object to separate reversibly into smaller components, as...
 Kd. A good fit corresponds with high affinity and low Kd. The final biological response (e.g. second messenger cascade
Second messenger system

In cell physiology, a secondary messenger system is a method of cellular signaling, whereby a diffusable signaling molecule is rapidly produced/secreted which can then go on to activate effector proteins within the cell to exert a cellular response....
 or muscle contraction), is only achieved after a significant number of receptors are activated.

If the receptor exists in two states (see ), then the ligand binding must account for these two receptor states. For a more detailed discussion of two-state binding, which is thought to occur as an activation mechanism in many receptors see .

Constitutive activity

A receptor which is capable of producing its biological response in the absence of a bound ligand is said to display "constitutive activity." The constitutive activity of receptors may be blocked by inverse agonist
Inverse agonist

In pharmacology, an inverse agonist is an agent which binds to the same receptor binding-site as an agonist for that receptor and reverses Receptor #Constitutive activity of receptors....
 binding. Mutations in receptors that result in increased constitutive activity underlie some inherited diseases, such as precocious puberty (due to mutations in luteinizing hormone receptors) and hyperthyroidism (due to mutations in thyroid-stimulating hormone receptors). Psychostimulant
Psychostimulant

A psychostimulant is a substance that enhances locomotor behavior. Examples of psychostimulants include amphetamine, methamphetamine, cocaine, methylphenidate, and arecoline, the most widely used psychostimulant....
s act as inverse agonists on dopamine receptors.

For the use of statistical mechanics
Statistical mechanics

Statistical mechanics is the application of probability theory, which includes Mathematics tools for dealing with large populations, to the field of mechanics, which is concerned with the motion of particles or objects when subjected to a force....
 in a quantitative study of the ligand-receptor binding affinity, see the comprehensive article on the configuration integral
Configuration integral

The classical configuration integral, more commonly called the partition function , andsometimes referred to asthe configurational partition function,...
.

Agonist
Agonist

An agonist is a term used to describe a type of Ligand or drug that binds and alters the activity of a Receptor . The ability to alter the activity of a receptor, also known as the agonist's efficacy is a property that distinguishes it from receptor antagonist, a type of receptor ligand which also binds a receptor but which does not alter t...
s versus antagonists
Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a Receptor , but blocks or dampens agonist-mediated responses....
 

Not every ligand that binds to a receptor also activates the receptor. The following classes of ligands exist:

  • (Full) agonists are able to activate the receptor and result in a maximal biological response. Most natural ligands are full agonists.
  • Partial agonists do not activate receptors thoroughly, causing responses which are partial compared to those of full agonists.
  • Antagonists bind to receptors but do not activate them. This results in receptor blockage, inhibiting the binding of other agonists.
  • Inverse agonists reduce the activity of receptors by inhibiting their constitutive activity.


Peripheral membrane protein receptors


Transmembrane receptors


Metabotropic receptors


G protein-coupled receptors
These receptors are also known as seven transmembrane receptors or 7TM receptors, because they pass through the membrane seven times.
  • Muscarinic acetylcholine receptor
    Muscarinic acetylcholine receptor

    Muscarinic receptors, or mAChRs, are G protein-coupled receptor acetylcholine receptors found in the plasma membranes of certain neurons and other Cell s....
     (Acetylcholine
    Acetylcholine

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

    Muscarine, L--muscarine, or muscarin is a Secondary metabolite found in certain mushrooms, particularly in Inocybe and Clitocybe species, such as the deadly Clitocybe dealbata....
    )
  • Adenosine receptor
    Adenosine receptor

    The adenosine receptors are a class of purinergic receptors, G-protein coupled receptors with adenosine as endogenous ligand.In humans, there are four adenosine receptors....
    s (Adenosine
    Adenosine

    Adenosine is a nucleoside composed of a molecule of adenine attached to a ribose sugar molecule moiety via a ?-N9-glycosidic bond....
    )
  • Adrenoceptors (also known as Adrenergic receptor
    Adrenergic receptor

    The adrenergic receptors are a class of G protein-coupled receptors that are targets of the catecholamines. Adrenergic Receptor s specifically bind and are activated by their endogenous ligands, the catecholamines adrenaline and noradrenaline ....
    s, for adrenaline, and other structurally related hormone
    Hormone

    Hormones are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism....
    s and drugs
    Medication

    A pharmaceutical drug, also referred to as medicine or medicament, can be loosely defined as any substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease....
    )
  • GABA receptor
    GABA receptor

    The GABA receptors are a class of Receptor that respond to the neurotransmitter Gamma-aminobutyric acid , the chief inhibitory neurotransmitter in the vertebrate central nervous system....
    s, Type-B (?-Aminobutyric acid
    Gamma-aminobutyric acid

    γ-Aminobutyric acid is the chief inhibitory neurotransmitter in the mammalian central nervous system. It plays an important role in regulating neuronal excitability throughout the nervous system....
     or GABA)
  • Angiotensin receptor
    Angiotensin receptor

    The angiotensin receptors are a class of G protein-coupled receptors with angiotensins as Ligand s. They are important in the renin-angiotensin system: they are responsible for the signal transduction of the main effector hormone....
    s (Angiotensin
    Angiotensin

    Angiotensin causes blood vessels to constrict, and drives blood pressure up. It is part of the renin-angiotensin-aldosterone system, which is a major target for drugs that lower blood pressure....
    )
  • Cannabinoid receptor
    Cannabinoid receptor

    The cannabinoid receptors are a class of Receptor s under the G-protein coupled receptor superfamily. Their ligand s are known as cannabinoids or endocannabinoids depending on whether they come from external or internal sources, respectively....
    s (Cannabinoids
    Cannabinoids

    Cannabinoids are a group of terpenephenolic compounds present in Cannabis . The broader definition of cannabinoids refers to a group of substances that are structurally related to tetrahydrocannabinol or that bind to cannabinoid receptors....
    )
  • Cholecystokinin receptor
    Cholecystokinin receptor

    Cholecystokinin receptors or CCK receptors are a group of G-protein coupled receptors which bind the peptide hormones cholecystokinin or gastrin....
    s (Cholecystokinin
    Cholecystokinin

    Cholecystokinin is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein. Cholecystokinin, previously called pancreozymin, is synthesised by I-cells in the mucosal epithelium of the small intestine and secreted in the duodenum, the first segment of the small intestine, and ca...
    )
  • Dopamine receptor
    Dopamine receptor

    Dopamine receptors are a class of metabotropic receptor G protein-coupled receptors that are prominent in the vertebrate central nervous system ....
    s (Dopamine
    Dopamine

    Dopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the human brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors ? D1, D2, D3, D4 and D5, and their variants....
    )
  • Glucagon receptor
    Glucagon receptor

    The glucagon receptor is a 62 kDa peptide that is activated by glucagon and is a member of the G-protein coupled family of receptors, coupled to Gs alpha subunit....
    s (Glucagon
    Glucagon

    Glucagon is an important hormone involved in carbohydrate metabolism. Produced by the pancreas, it is released when the glucose level in the blood is low , causing the liver to convert stored glycogen into glucose and release it into the bloodstream....
    )
  • Metabotropic glutamate receptor
    Metabotropic glutamate receptor

    The metabotropic glutamate receptors, or mGluRs, are a type of glutamate receptor which are active through an indirect metabotropic receptor process....
    s (Glutamate)
  • Histamine receptor
    Histamine receptor

    The histamine receptors are a class of G-protein coupled receptors with histamine as their endogenous ligand.There are four known histamine receptors:...
    s (Histamine
    Histamine

    Histamine is a biogenic amine involved in local immune system as well as regulating physiological function in the gut and acting as a neurotransmitter....
    )
  • Olfactory receptor
    Olfactory receptor

    Olfactory receptors expressed in the cell membranes of olfactory receptor neurons are responsible for the detection of odor molecules. Activated olfactory receptors are the initial player in a signal transduction cascade which ultimately produces a nerve impulse which is transmitted to the brain....
    s (for the sense of smell
    Olfaction

    Olfaction refers to the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates....
    )
  • Opioid receptor
    Opioid receptor

    Opioid receptors are a group of G-protein coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins and nociceptin....
    s (Opioid
    Opioid

    An opioid is a chemical substance that has a morphine-like action in the body. The main use is for analgesia. These agents work by binding to opioid receptors, which are found principally in the central nervous system and the gastrointestinal tract....
    s)
  • Rhodopsin
    Rhodopsin

    Rhodopsin, also known as visual purple, is a pigment of the retina that is responsible for both the formation of the photoreceptor cells and the first events in the perception of light....
     (a photoreceptor
    Photoreceptor

    A photoreceptor, or photoreceptor cell, is a specialized type of neuron found in the eye's retina that is capable of phototransduction....
    )
  • Secretin receptor
    Secretin receptor

    Human secretin receptor is a G protein-coupled receptor which binds secretin and is the leading member of the class B GPCR subfamily....
    s (Secretin
    Secretin

    Secretin is a peptide hormone produced in the S cells of the duodenum in the crypts of Lieberk?hn. Its primary effect is to regulate the pH of the duodenal contents via the control of gastric acid secretion and buffering with bicarbonate....
    )
  • Serotonin receptors, except Type-3 (Serotonin
    Serotonin

    Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
    , also known as 5-Hydroxytryptamine or 5-HT)
  • Somatostatin receptor
    Somatostatin receptor

    There are five known somatostatin receptors:* somatostatin receptor 1 * somatostatin receptor 2 * somatostatin receptor 3 * somatostatin receptor 4 ...
    s (Somatostatin
    Somatostatin

    Somatostatin is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G-protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones....
    )
  • Calcium-sensing receptor
    Calcium-sensing receptor

    The calcium-sensing receptor is a G-protein coupled receptor which senses extracellular levels of calcium ion. In the parathyroid gland, the calcium-sensing receptor controls calcium homeostasis by regulating the release of parathyroid hormone....
     (Calcium
    Calcium

    Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft grey alkaline earth metal, and is the fifth most abundant element by mass in the earth's Crust ....
    )
  • Chemokine receptors (Chemokines)
  • many more ...


Receptor tyrosine kinases
These receptors detect ligands and propagate signals via the tyrosine kinase
Tyrosine kinase

A tyrosine kinase is an enzyme that can transfer a phosphate group from Adenosine triphosphate to a tyrosine residue in a protein. Tyrosine kinases are a subgroup of the larger class of protein kinases....
 of their intracellular domains. This family of receptors includes;
  • Erythropoietin receptor
    Erythropoietin receptor

    The erythropoietin receptor is a 66 atomic mass unit peptide consisting of two peptide chains and is a member of the cytokine receptor family. Upon binding of a 34 kDa ligand erythropoietin , the two chains of the EpoR undergo a conformational change resulting in the autophosphorylation of Jak2 kinases that are pre-associated with the recept...
     (Erythropoietin
    Erythropoietin

    Erythropoietin, or its alternative erythropoetin or EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production....
    )
  • Insulin receptor
    Insulin receptor

    In molecular biology, the insulin receptor is a transmembrane receptor receptor that is activated by insulin. It belongs to the large class of tyrosine kinase receptors....
     (Insulin
    Insulin

    Insulin is a hormone with extensive effects on both metabolism and several other body systems . Insulin causes most of the body's cells to take up glucose from the blood , storing it as glycogen in the liver and muscle, and stops use of fat as an energy source....
    )
  • Eph receptor
    Eph receptor

    In molecular biology, ephrins and Eph Receptor are components of cell signaling pathways involved in animal developmental biology, and implicated in some cancers....
    s
  • Insulin-like growth factor 1 receptor
  • various other growth factor
    Growth factor receptor

    A growth factor receptor is a Receptor which binds to growth factor.External links...
     and cytokine receptor
    Cytokine receptor

    A Cytokine receptor is a Receptor which binds cytokines.In recent years, the cytokine receptors have come to demand the attention of more investigators than cytokines themselves, partly because of their remarkable characteristics, and partly because a deficiency of cytokine receptors has now been directly linked to certain debilitating imm...
    s
  • ....


Guanylyl cyclase receptors
  • GC-A & GC-B: receptors for Atrial-natriuretic peptide (ANP) and other natriuretic peptides
  • GC-C: Guanylin
    Guanylin

    Guanylin is a 15 amino acid peptide that is secreted by goblet cells in the Colon . Guanylin acts as an agonist of the guanylyl cyclase receptor GC-C and regulates electrolyte and water transport in intestinal and renal epithelia....
     receptor


Ionotropic receptors

Ionotropic receptors are heteromeric or homomeric
Homomeric

A substance which is made out of any number of identical products or molecules. e.g. A homomeric peptide = glutathione A peptide which is made up of only a single type of amino acid subunit; e.g., alanylalanylalanine...
 oligomers . They are receptors that respond to extracellular ligands and receptors that respond to intracellular ligands.

Extracellular ligands
Receptor Ligand Ion current
Nicotinic acetylcholine receptor
Nicotinic acetylcholine receptor

Nicotinic acetylcholine receptors, or nAChRs, are cholinergic receptors that form ligand-gated ion channels in the plasma membranes of certain neurons....
 		 Acetylcholine
Acetylcholine

The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including homo sapiens....
, Nicotine
Nicotine

Nicotine is an alkaloid found in the nightshade family of plants which constitutes approximately 0.6?3.0% of dry weight of tobacco, with biosynthesis taking place in the roots, and accumulating in the leaves....
 		 Na+, K+, Ca2+
Glycine receptor
Glycine receptor

The glycine receptor, or GlyR, is the receptor for the amino acid neurotransmitter glycine. It is one of the most widely distributed inhibitory receptors in the central nervous system and has important roles in a variety of physiological processes, especially in mediating inhibitory neurotransmission in the spinal cord and brain ste...
 (GlyR) 		Glycine
Glycine

Glycine is the organic compound with the chemical formula NH2CH2COOH. It is the smallest of the 20 amino acids commonly found in proteins, coded by codons GGU, GGC, GGA and GGG....
, Strychnine
Strychnine

Strychnine is a very toxic , colorless crystalline alkaloid used as a pesticide, particularly for killing small vertebrates such as birds and rodents....
  		Cl- > HCO-3
GABA receptor
GABA receptor

The GABA receptors are a class of Receptor that respond to the neurotransmitter Gamma-aminobutyric acid , the chief inhibitory neurotransmitter in the vertebrate central nervous system....
s: GABA-A, GABA-C 		GABA
Gabā

Gab? or gabaa, for the Cebuano people , is the concept of a non-human and non-divine, imminent Retributive justice. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions....
  		Cl- > HCO-3
Glutamate receptor
Glutamate receptor

Glutamate receptors are transmembrane receptors located on neuron membranes. These receptors bind the neurotransmitter glutamate....
s: NMDA receptor
NMDA receptor

The NMDA receptor is an ionotropic receptor for glutamate . Activation of NMDA receptors results in the opening of an ion channel that is nonselective to ion....
, AMPA receptor
AMPA receptor

The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor is a non-NMDA-type ionotropic receptor transmembrane receptor for glutamate that mediates fast synapse transmission in the central nervous system ....
, and Kainate receptor
Kainate receptor

Kainate receptors, or KARs, are non-NMDA ionotropic receptors which respond to the neurotransmitter glutamate. They were first identified as a distinct receptor type through their selective activation by the agonist kainate, a drug first isolated from red alga Digenea simplex....
 		 Glutamate Na+, K+, Ca2+
5-HT3 receptor Serotonin
Serotonin

Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
 		 Na+, K+
P2X receptors ATP
Adenosine triphosphate

This article is about the chemical used by cells as an energy carrier. For other uses, see ATP .Adenosine-5'-triphosphate is a multifunctional nucleotide, and plays an important role in cell biology as a coenzyme that is the "molecule unit of currency" of intracellular energy transfer....
 		 Ca2+, Na+, Mg2+


Intracellular ligands
Receptor Ligand Ion current
cyclic nucleotide-gated ion channel
Cyclic nucleotide-gated ion channel

A cyclic nucleotide-gated ion channel is any ion channel that opens in the presence of cyclic nucleotides....
s 		cGMP
Cyclic guanosine monophosphate

Cyclic guanosine monophosphate is a cyclic nucleotide derived from guanosine triphosphate . cGMP acts as a second messenger much like cyclic AMP, most notably by activating intracellular protein kinases in response to the binding of cell membrane-impermeable peptide hormones to the external cell surface....
 (vision
Visual system

The visual system is the part of the central nervous system which allows organisms to visual perception.It interprets the information from visible light to build a representation of the world surrounding the body....
), cAMP
Cyclic adenosine monophosphate

Cyclic adenosine monophosphate is a second messenger that is important in many biological processes. cAMP is derived from adenosine triphosphate and used for intracellular signal transduction in many different organisms....
 and cGTP (olfaction
Olfaction

Olfaction refers to the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates....
) 		Na+, K+
IP3 receptor
Inositol triphosphate receptor

Inositol triphosphate receptor is a membrane glycoprotein complex acting as calcium channel activated by inositol triphosphate . The IP3 receptor was first purified from rat cerebellum....
 		 IP3
Inositol triphosphate

Inositol trisphosphate or inositol 1,4,5-trisphosphate , together with diglyceride, is a secondary messenger molecule used in signal transduction in cell s....
 		 Ca2+
Intracellular ATP
Adenosine triphosphate

This article is about the chemical used by cells as an energy carrier. For other uses, see ATP .Adenosine-5'-triphosphate is a multifunctional nucleotide, and plays an important role in cell biology as a coenzyme that is the "molecule unit of currency" of intracellular energy transfer....
 receptors 		ATP
Adenosine triphosphate

This article is about the chemical used by cells as an energy carrier. For other uses, see ATP .Adenosine-5'-triphosphate is a multifunctional nucleotide, and plays an important role in cell biology as a coenzyme that is the "molecule unit of currency" of intracellular energy transfer....
 (closes channel) 		K+
Ryanodine receptor
Ryanodine receptor

Ryanodine receptors form a class of intracellular calcium channels in various forms of excitable animal tissue like muscles and neurons. It is the major cellular mediator of calcium-induced calcium release in animal cell s....
 		 Ca2+ Ca2+


The entire repertoire of human plasma membrane receptors is listed at the Human Plasma Membrane Receptome (http://www.receptome.org).

Intracellular receptors


Transcription factors

  • nuclear receptor
    Nuclear receptor

    In the field of molecular biology, nuclear receptors are a class of proteins found within the interior of cells that are responsible for sensing the presence of hormone and certain other molecules....
    :
    • Steroid hormone receptor
      Steroid hormone receptor

      Steroid hormone receptors are found on the plasma membrane, in the cytosol and also in the nucleus of target cells. They are generally intracellular receptors and initiate signal transduction for steroid hormones which lead to changes in gene expression over a time period of hours to days....


Various

  • Ionotropic receptors (IP3 receptor
    Inositol triphosphate receptor

    Inositol triphosphate receptor is a membrane glycoprotein complex acting as calcium channel activated by inositol triphosphate . The IP3 receptor was first purified from rat cerebellum....
     above)
  • sigma1
    Sigma-1 receptor

    The sigma-1 receptor is a Chaperone at the endoplasmatic reticulum that modulates calcium signaling through the IP3 receptor.The sigma-1 receptor is a transmembrane protein expressed in many different tissue types....
     (neurosteroids
    Neuroactive steroid

    Neuroactive steroids rapidly alter neuronal excitability through interaction with neurotransmitterligand-gated ion channels. In addition, these steroids may also exert effects on gene expression via intracellular steroid hormone receptors....
    )
  • G protein-coupled receptors


Role in Genetic Disorders

Many genetic disorder
Genetic disorder

A genetic disorder is an illness caused by abnormalities in genes or chromosomes. While some diseases, such as cancer, are due in part to a genetic disorders, they can also be caused by Environment factors....
s involve hereditary defects in receptor genes. Often, it is hard to determine whether the receptor is nonfunctional or the hormone
Hormone

Hormones are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism....
 is produced at decreased level; this gives rise to the "pseudo-hypo-" group of endocrine disorders
Endocrinology

Endocrinology is a branch of medicine dealing with disorder of the endocrine system and its specific secretions called hormones....
, where there appears to be a decreased hormonal level while in fact it is the receptor that is not responding sufficiently to the hormone.

Receptor Regulation

Cells can increase (upregulate) or decrease (downregulate) the number of receptors to a given hormone
Hormone

Hormones are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism....
 or neurotransmitter
Neurotransmitter

Neurotransmitters are chemistry which relay, amplify and modulate signals between a neuron and another cell . Neurotransmitters are packaged into vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of...
 to alter its sensitivity to this molecule. This is a locally acting feedback
Feedback

Feedback describes the situation when output from an event or phenomenon in the past will influence the same event/phenomenon in the present or future....
 mechanism.

Receptor desensitization Ligand-bound desensitation Vol. 135. No. 5 2130-2136
  • Uncoupling of receptor effector molecules.
  • Receptor sequestration (internalization).


In immune system

The main receptors in the immune system
Immune system

An immune system is a collection of biological processes within an organism that protects against disease by identifying and killing pathogens and tumour cells....
 are pattern recognition receptors (PRRs), Toll-like receptor
Toll-like receptor

Toll-like receptors are a class of proteins that play a key role in the innate immune system. They are single membrane-spanning non-catalytic Receptor that recognize structurally conserved molecules derived from microbes....
s (TLRs), killer activated and killer inhibitor receptors (KARs and KIRs), complement receptor
Complement receptor

A complement receptor is a receptor of the complement system, a part of the mediated innate immune system. Complement receptors are responsible for detecting pathogens by mechanisms not mediated by antibody....
s, Fc receptors, B cell receptors and T cell receptor
T cell receptor

The T cell receptor or TCR is a molecule found on the surface of T lymphocytes that is, in general, responsible for recognizing antigens bound to major histocompatibility complex molecules....
s.

See also

  • Signal transduction
    Signal transduction

    In biology, 'signal transduction' refers to any process by which a cell converts one kind of signal or stimulus into another. Most processes of signal transduction involve ordered sequences of biochemistry chemical reaction inside the cell, which are carried out by enzymes, activated by Second messenger systems, resulting in a signal tran...
  • Neuropsychopharmacology
    Neuropsychopharmacology

    Technical advancements in recent years have allowed progress toward the understanding of the brain and how psychoactive drug can be made to affect it....
  • Schild regression
    Schild regression

    Schild regression analysis, named for Heinz Otto Schild, is a useful tool for studying the effects of agonists and antagonists on the cellular response caused by the receptor or on ligand-receptor binding....
     for ligand receptor inhibition
  • Ki Database
    Ki Database

    The Ki Database is a public domain database of published dissociation constant of drugs and chemical compounds for receptor , neurotransmitter transporters, ion channels, and enzymes....
  • Wikipedia:MeSH D12.776#MeSH D12.776.543.750 --- receptors.2C cell surface


External links