The protein encoded by this gene is a member of the pexin family. It is found in serum and tissues and promotes cell adhesion and spreading, inhibits the membrane-damaging effect of the terminal cytolytic complement pathway, and binds to several serpin serine protease inhibitors. It is a secreted protein and exists in either a single chain form or a clipped, two chain form held together by a disulfide bond. [provided by RefSeq, Jul 2008],domain:The SMB domain mediates interaction with SERPINE1/PAI1. The heparin-binding domain mediates interaction with insulin.,function:Somatomedin-B is a growth hormone-dependent serum factor with protease-inhibiting activity.,function:Vitronectin is a cell adhesion and spreading factor found in serum and tissues. Vitronectin interact with glycosaminoglycans and proteoglycans. Is recognized by certain members of the integrin family and serves as a cell-to-substrate adhesion molecule. Inhibitor of the membrane-damaging effect of the terminal cytolytic complement pathway.,PTM:It has been suggested that the active SMB domain may be permitted considerable disulfide bond heterogeneity or variability, thus two alternate disulfide patterns based on 3D structures are described with 1 disulfide bond conserved in both.,PTM:N- and O-glycosylated.,PTM:Phosphorylation on Thr-69 and Thr-76 favors cell adhesion and spreading.,PTM:Sulfated on 2 tyrosine residues.,similarity:Contains 1 SMB (somatomedin-B) domain.,similarity:Contains 4 hemopexin-like domains.,subunit:Exists in two forms: a single chain 75 kDa form (V75) and a clipped form composed of two chains (65 kDa and 10 kDa) (V65+V10) which are held together by a disulfide bond. Interacts with SERPINE1/PAI1 and insulin.,tissue specificity:Plasma.,