Plexin B2: ProductsPlexin B2 is a 240 kDa member of the B subfamily, Plexin family of semaphorin receptors. It is expressed by cerebellar granule cells, neuroepithelium and chondrocytes and serves as a receptor for Sema4C. Mature human Plexin B2 is 1819 amino acid (aa) in length. It is a type I transmembrane (TM) glycoprotein that contains an 1178 aa extracellular domain (ECD) plus a 620 aa cytoplasmic region. The ECD contains one semaphorin domain (aa 20 - 466) and three IPT repeats (aa 803 - 1092). The ECD may be cleaved into two subunits, a 170 kDa alpha-chain (aa 20 - 1164) and an 80 kDa TM beta-chain that remain noncovalently-linked. Multiple splice variants may exist. One shows an alternate start site at Met1369, while a second shows a deletion of aa 67 - 638. Over aa 20 - 1160, human Plexin B2 is 82% aa identical to mouse Plexin B2.