Decoy receptors, membrane-binding

Fig. 8. Schematic representation of aberrant mFas, which is expected to attenuate the Fas-mediated signaling. Aberrant mFas is functionally and structurally classified into main three types (a) the membrane-binding decoy receptor, (b) the membrane-binding decorative receptor, and (c) the membrane-unstable or soluble receptor. Although both mFas in models (a) and (b) are normally fixed on the membrane, the mFas in the former can bind Fas ligand, but is defective for trimerization, whereas the mFas in the latter would have no ability to bind Fas ligand in vivo because of conformational alteration. Like model (a), the mFas in model (c) can be reactive for Fas ligand, but it cannot transduce the apoptotic signal into the cytoplasmic death cascade because of incomplete trimerization due to an abnormal TM domain or truncation of the 1C domain. The hatched and jagged markings indicate deduced alterations of amino acid sequence or three-dimensional structure, respectively.

When the ODF/ODAR complex activates c-src to form a ruffled membrane, it also activates NFkB to activate the transcription factors that induce cathepsin K and acid phosphatase expression. Because ODF binds to ODAR/RANK, it is also known as the RANK ligand (RANKL). OCIF (OPG), the ODF decoy receptor, is RANK without its transmembrane and cytosolic domains. Thus OCIF = OPG and OPG ligand (OPGL) = RANKL = ODF. ODF, ODAR, and OCIF are related to TNFa or its receptor, TNFa family molecules (Table 10.1). 

As previously mentioned, interferons are cytokines produced by cells to protect them from viral infection, and anti-interferon strategies are a part of the immune evasion repertoire of most viruses. These mechanisms include the production of soluble versions of interferon receptors, which act as decoys. These decoys bind and inactivate interferons before they reach their destination - normal, membrane-bound receptors.22... 

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