Semaphorin-4A (E5N3K) Rabbit Monoclonal Antibody (Alexa Fluor^® 647 Conjugate) #31004

Semaphorin-4A, or Sema4A, is a membrane-type class IV semaphorin family member glycoprotein and is expressed in dendritic cells, B cells, T cells, and endothelial cells (1). The protein structure consists of an N-terminus signal peptide, a sema domain, a C2 type Ig domain, a transmembrane region, and a cytoplasmic tail (2). Semaphorin-4A exerts diverse biological effects through several different receptor-mediated pathways and plays important roles in immunity, angiogenesis, neuronal migration, and tumor progression. Semaphorin-4A enhances T cell activation by interacting with TIM-2, and T cell-derived Semaphorin-4A plays a role in helper T cell (Th) differentiation (3,4). In regulatory T cells (Tregs), Semaphorin-4A plays an important role in enhancing stability through interactions with neuropilin-1 (Nrp1) (5). Semaphorin-4A interacts with Plexin D1, which is expressed in endothelial cells and negatively regulates angiogenesis (6). In presynaptic neurons, Semaphorin-4A promotes the development of inhibitory or excitatory synapses through interactions with Plexin B1 or Plexin B2, respectively (7). Semaphorin-4A has been identified as a therapeutic target to promote antitumor responses, and its expression in the tumor microenvironment (TME) has been suggested as a biomarker to predict response to immunotherapy (8).