- Cytokine receptor
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Cytokine receptors are receptors that bind cytokines.[1]
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 immunodeficiency states. In this regard, and also because the redundancy and pleiotropy of cytokines are, in fact, a consequence of their homologous receptors, many authorities are now of the opinion that a classification of cytokine receptors would be more clinically and experimentally useful.
Contents
Classification
A classification of cytokine receptors based on their three-dimensional structure has been attempted. (Such a classification, though seemingly cumbersome, provides several unique perspectives for attractive pharmacotherapeutic targets.)
- Type I cytokine receptors, whose members have certain conserved motifs in their extracellular amino-acid domain. The IL-2 receptor belongs to this chain, whose γ-chain (common to several other cytokines) deficiency is directly responsible for the x-linked form of Severe Combined Immunodeficiency (X-SCID).
- Type II cytokine receptors, whose members are receptors mainly for interferons.
- Immunoglobulin (Ig) superfamily, which are ubiquitously present throughout several cells and tissues of the vertebrate body
- Tumor necrosis factor receptor family, whose members share a cysteine-rich common extracellular binding domain, and includes several other non-cytokine ligands like CD40, CD27 and CD30, besides the ligands on which the family is named (TNF).
- Chemokine receptors, two of which acting as binding proteins for HIV (CXCR4 and CCR5). They are G protein coupled receptors.
- TGF beta receptors
Comparison
Type Examples Structure Mechanism type I cytokine receptor - Type 1 interleukin receptors
- Erythropoietin receptor
- GM-CSF receptor
- G-CSF receptor
- growth hormone receptor
- prolactin receptor
- Oncostatin M receptor
- Leukemia inhibitory factor receptor
Certain conserved motifs in their extracellular amino-acid domain. Connected to Janus kinase (JAK) family of tyrosine kinases JAK phosphorylate and activate downstream proteins involved in their signal transduction pathways type II cytokine receptor - Type II interleukin receptors
- interferon-alpha/beta receptor
- interferon-gamma receptor
Many members of the immunoglobulin superfamily Share structural homology with immunoglobulins (antibodies), cell adhesion molecules, and even some cytokines. Tumor necrosis factor receptor family cysteine-rich common extracellular binding domain chemokine receptors - Interleukin-8 receptor
- CCR1
- CXCR4
- MCAF receptor
- NAP-2 receptor
Seven transmembrane helix G protein-coupled TGF beta receptors Solubility
Cytokine receptors may be both membrane-bound and soluble. Soluble cytokine receptors are extremely common regulators of cytokine function.
See also
References
- ^ Richard Coico; Geoffrey Sunshine (2009). Immunology: a short course. Wiley-Blackwell. pp. 174–. ISBN 9780470081587. http://books.google.com/books?id=Lxcj-PlALiIC&pg=PA174. Retrieved 28 November 2010.
External links
Cytokine receptors Chemokine receptor
(GPCRs)OtherTNF receptor 1-1011-2021-25JAK-STAT OtherIg superfamily IL-17 family S/T B trdu: iter (nrpl/grfl/cytl/horl), csrc (lgic, enzr, gprc, igsr, intg, nrpr/grfr/cytr), itra (adap, gbpr, mapk), calc, lipd; path (hedp, wntp, tgfp+mapp, notp, jakp, fsap, hipp, tlrp) This membrane protein-related article is a stub. You can help Wikipedia by expanding it. This article about a biochemical receptor is a stub. You can help Wikipedia by expanding it.