Semaphorin 4A Products

Description

Semaphorin 4A (Sema4A), also known as Semaphorin-B (SEMB), is a Class 4 transmembrane Semaphorin with activity in the immune and nervous systems (1). Semaphorins are a large family of secreted and membrane-bound glycoproteins, divided into eight subclasses, that were initially implicated in axon guidance and neural development. Mature Sema4a consists of an extracellular domain (ECD) containing sema, PSI and C2-type immunoglobulin domains, a transmembrane domain, and a cytoplasmic domain with two Ser/Thr phosphorylation sites. The ECD of mature mouse Sema4A shares 87% and 94% amino acid sequence identity with human and rat Sema4a, respectively. Several splice variants have been reported with varying truncations in the ECD, transmembrane or cytoplasmic domains (3). Sema4A was first described as a molecule that enhances T cell activation and interacts with TIM-2 (T cell immunoglobulin and mucin domain-2 (4). Sema4a has also been shown to bind to the receptor ILT-4 on activated CD4+ cells (5). Mice with targeted disruption of Sema4A show defects in dendritic cell-mediated T cell priming and Th1 responses (6). Roles for Sema4A have also been identified in the brain, the endothelium and the eye. It mediates hippocampal neuron growth cone collapse in vitro through interaction of the sema domain with plexin-B1 (7). Interaction of Sema4A with endothelial cell plexin-D1 causes opposition to the angiogenic, proliferative, chemotactic and integrin-mediated adhesive actions of VEGF (8). The retina of Sema4A-/- mice shows severe degeneration, and mutations of Sema4A are associated with retinitis pigmentosa and cone rod dystrophy in humans (9, 10).

Bioinformatics

Uniprot	Q62178.2
Product By Gene ID	64218
Alternate Names	CORD10 RP35 Sema B sema domain, immunoglobulin domain (Ig), transmembrane domain (TM) and shortcytoplasmic domain, (semaphorin) 4A SEMA4A SEMAB Semaphorin 4A semaphorin-4A semaphorin-B SEMB SEMBFLJ12287