WSXWS motif

In the extracellular region, cytokine receptors have characteristic sequence sections that specify the particular receptor type. Cys-rich domains, fibronectin type Ill-like domains and immimoglobulin-like domains can be differentiated. Cytokine receptors of type I often have a conserved WSXWS motif in the extracellular region. 

The P-chain (a polypeptide with 70 to 75kDa, called p70 or p75, CD 122) is a member of the receptor family characterized by the WSXWS motif and is expressed coordinately with the y-chain (a 64-kDa polypeptide, also a member of the WSXWS family) forming a complex designated IL-2Rafly. This is the intermediate-affinity receptor (iQ 10 M) for IL-2, expressed constitutively by resting T lymphocytes (also by CDS T cytotoxic cells). It is not expressed by CD4 Th... 

IL-IOR is a single-chain receptor. IL-IOR belongs to the class II cytokine receptor family that also includes the IFN receptors (IFNy and IFNap receptors). The extracellular region consists of two homologous fibronectin type III domains that are without the WSXWS motif characteristic of class I cytokine receptors. It is expressed on B cells, thymocytes, and other cellular lines such as mast cells and macrophages. Human IL-IOR mRNA is restricted mostly to hematopoietic cells and cell lines. ... 

IL-12 is homologous to the IL-6R, containing an Ig domain and a WSXWS motif. Thus, IL-12 appears to be composed of one cytokine-like polypeptide and one receptor-like polypeptide. ... 

In the extracellular region, cytokine receptors have characteristic sequence sections that specify the particular receptor type. Cys-rich domains, fibronectin-type IH-like domains and immunoglobulin-like domains can be differentiated, among others. Cytokine receptors of type I often have a conserved WSXWS motif in the extracellular region. With the exception of ciliary neurotrophic receptor, which is membrane-anchored via a GPI anchor (see Section 3.7.4), all receptors have a single transmembrane domain of 22 - 28 amino acids. Two motifs, called box 1 and box 2, are relatively conserved in the membrane-proximal part of the cytoplasmic domain. However, no known catalytic domain is found on the cytoplasmic part of the receptors. 

Fig. 11.3 Schematic model of the IL-6/gpl 30 receptor system. The specific cytokine-binding subunits and gpl30 belong to a cytokine receptor family characterized by four positionally conserved cysteine and a WSXWS motif. Functional receptor complexes are induced by the different cytokines IL-6 and IL-11 induce gpl30 homodimerization. CNTF, LIF, CT-1 and OSM induce LIFRa/gpl30...

Fig. 11.2. Domain structure of cytokine receptors. Schematic representation of the domain structure of selected cytokine receptors. WS motif conserved WSXWS sequence (W tryptophan S serine X non-conserved amino add) IL interleukin EpoR receptor for erythropoietin GHR growth hormone receptor LIF-R leukemia inhibitory factor receptor G-CSFR granulocyte colony stimulating factor receptor IFNR interferon receptor TNFR tumor necrosis factor receptor NGFR nerve growth factor receptor Fas, CD40 transmembrane receptors of lymphocytes.

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