Inhibitory Receptors and Their Modes of Action
This extract was created in the absence of an abstract.
Excerpt
One of the most remarkable advances in immunologyin the past decade has been recognition and characterization of a family of receptors that function as inhibitors or,minimally, modulators, of activating immune system receptor function. These receptors exhibit several commonfeatures. They are single membrane spanning glycoproteins whose function is triggered when they are co-aggregated by complex ligands with protein tyrosine kinase(PTK)-activating receptors. This activity is dependent onphosphorylation by kinases activated by the co-aggregated PTK-coupled receptor. This phosphorylation occurs on tyrosines located in specific sequence motifswithin the cytoplasmic tail. This motif, termed the immunoreceptor tyrosine-based inhibitor motif, or ITIM,may occur in multiple copies and mediates inhibitory signaling by recruitment of phosphoinositol and/or phosphotyrosine phosphatases. In this paper, we briefly review the breadth of this receptor family and discuss themolecular mode of action of the first recognized memberof the family, FcγRIIB. For more in-depth discussion, thereader is referred to excellent recent reviews by Coggeshall (1998), Long (1999), and Leibson (1997)...
