V-Set And Immunoglobulin Domain Containing Protein 4 (VSIG4)

VSIG4 encodes a v-set and immunoglobulin-domain containing protein that is structurally related to the B7 family of immune regulatory proteins. This protein is also a receptor for the complement component 3 fragments C3b and iC3b. Alternate splicing results in multiple transcript variants.The deduced 399-amino acid transmembrane protein contains a signal peptide, a V-type Ig-like domain, a C2-type Ig-like domain, several potential O-glycosylation sites, and an intracellular domain with 2 potential phosphorylation sites. Northern blot analysis revealed expression of a 1.9-kb transcript in adult lung but not in other tissues tested. PCR analysis of cDNA libraries, however, detected ubiquitous expression of Z39IG in fetal and adult tissues, although the levels were relatively low in adult brain and skeletal muscle.