User:Janice C. Telfer/Group B SRCR domains

Group B Scavenger Receptor Cysteine-Rich (SRCR) DomainsGroup B Scavenger Receptor Cysteine-Rich (SRCR) Domains

Members of the group B SRCR domain family include CD5, CD6, DMBT1, Spα, WC1, CD163A, CD163b, and CD163c-α. (reviewed in Sarrias, M.R. 2004 Crit. Rev. in Immunology, 24:1-38; Herzig,C.T. and C.L. Baldwin 2009 BMC Genomics 10:191; and Herzig,C.T. et al 2010 Evol. Biology 10:181.) Some of these (i.e. WC1 and CD163c-α) are multi-gene families.

spinqualitylabelsall models Group B SRCR domain Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Group B SRCR domains are 100-110 amino acids long and are characterized by 6-8 cysteines, with conserved spacing. Disulfide bonds are formed between cysteines 1 and 4, 2 and 7, 3 and 8, and 5 and 6. Cysteines 2 and/or 7 are missing in some group B SRCR domains, resulting in the loss of one of the potential disulfide bonds. The crystal structure of the third SRCR domain of human CD5, which contains 8 cysteines, shows four disulfide bonds (Rodamilans, B. et. al. 2007 J. Biol Chem 282:12669-77 doi M611699200 [pii]10.1074/jbc.M611699200.)

Group B SRCR domains bind to both protein and non-petidic ligands. In the latter class of ligands are molecules found on bacteria, such as lipopolysaccharide (LPS) and lipoteichoic acid (LTA), which suggests that group B SRCR proteins play a role in the host immune response to microorganisms. The group B SRCR domain family member WC1 appears to play an important role in the bovine response to the spirochaete Leptospira as a co-receptor whose tyrosine phosphorylation is required for optimal gamma delta T cell response (Wang, F. et al 2009 Eur. J. Immunol. 39:254-66). There are approximately 15 different WC1 genes in the bovine genome (Herzig,C.T. and C.L. Baldwin 2009 BMC Genomics 10:191), but only a subset of them participate in the immune response to Leptospira (Rogers,A.N. et al 2005 J. Immunol. 174:3386-93). This subset is labelled by an antibody recognizing the first WC1 cloned, known as WC1.1. A subset labelled by an antibody recognizing the second WC1 cloned, known as WC1.2, does not participate in the immune response to Leptospira. Anti-WC1-1 recognizes SRCR domain 1 of WC1-1, WC1-3, WC1-11 and WC1-nd1; anti-WC1.2 recognizes SRCR domain 1 of WC1-4 and WC1-9 (Chen, C. et al 2009 Mol. Immunol. 46:2565-75).