Semaphorin-3B (SEMA3B)

Semaphorin-3B is a secreted guidance cue and member of the class 3 semaphorin family with important roles in neural development, particularly in axonal guidance by acting as a chemorepellent[3][5][8]. Structurally, it contains a sema domain, a plexin-semaphorin-integrin (PSI) domain, an immunoglobulin-like C2-type domain, and a basic domain[1][8]. SEMA3B signals through plexin-A family receptors, requiring co-receptors neuropilin-1 and neuropilin-2, and modulates kinase pathways[1][2]. It functions as a tumor suppressor by inhibiting angiogenesis—primarily by antagonizing VEGF165/neuropilin-1 interactions—inducing apoptosis, and blocking cell proliferation[1][2][4]. Loss or proteolytic inactivation of SEMA3B is linked to tumorigenesis in several cancers, and its deletion or decreased expression is a marker of more aggressive disease[2][4]. In addition, SEMA3B has been implicated in vascular development, immune cell regulation, bone remodeling, and fibrosis[1][7]. While currently not a direct drug target, it is considered a potential therapeutic and biomarker candidate, especially in oncology and fibrosis research.

Other names

Semaphorin 3BSEMA3BSEMA5SEMAASema VSemAsemaVLUCA-1sema5Sema A(V)Semaphorin-Vsema domain, immunoglobulin domain (Ig), short basic domain, secreted semaphorin 3Bsemaphorin A

Competes with VEGF165 for neuropilin-1 binding to downregulate tumor angiogenesis; Inhibits endothelial cell proliferation and survival; induces endothelial cell apoptosis; Modulates signal transduction through neuropilin-1 and neuropilin-2 co-receptors.