Semaphorin 4D, Fc Chimera, Recombinant, Human, aa22-734 (A8, BB18, CD100, COLL-4, M-sema-G, SEMA4D, SEMAJ)

Blue Ice

110135

Supplied as a lyophilized powder in PBS. BSA free. Reconstitute in 250ul sterile PBS.

Semaphorin 4D (Sema4D/CD100, previously Sem J, G or C­like 2) is a 150kD type I transmembrane glycoprotein that belongs to the Class 4 family of transmembrane immune and nervous system semaphorins (1­3). The human Sema4D cDNA encodes 862 amino acids (aa) that include a 21aa signal sequence, a 713aa extracellular domain (ECD), a 21aa transmembrane segment and a 107aa cytoplasmic tail. The Sema4D ECD contains one sema, PSI and immunoglobulin-like domain, and over the full ECD (aa22­734), human Sema4D shares 85%, 85%, 86% and 80% aa sequence identity with mouse, rat, porcine and canine Sema4D ECDs, respectively. Sema4D is active as a homodimer that utilizes both a membrane­proximal intermolecular disulfide bond and two hydrophobic interactions involving Phe244 and Phe246 (4, 5). Proteolysis by metalloproteinases such as TACE/ADAM17 and MMP­14 (MT1­MMP) produce a soluble, active 120kD form that may also exist as a dimer (5­7). Sema4D, produced by T cells, activated B cells and dendritic cells acts through a low affinity receptor termed CD72 in the immune system (1, 2). Unligated CD72 inhibits antigen presenting cells that express it, and this inhibition is relieved by Sema4D binding (8). Sema4D thus causes enhanced B cell survival, differentiation of macrophages and DC, and enhanced T cell antigen priming (2, 8, 9). In the CNS, Sema4D and a high affinity receptor Plexin B1 are expressed in complimentary patterns in several regions of the brain, and their interaction assists in the guidance of developing neurons (10). Intermediate affinity Sema4D:Plexin B2 binding also occurs during development, and enhances both radial and tangential neuronal migration (11). In cancer, Sema4D can also be produced by tumor­associated macrophages, and bind to endothelial cell Plexin B1, thus promoting tumor angiogenesis (3, 6, 7, 12). While this suggests facilitation of the metastatic process, it is also recognized that semaphorins in general show both tumor promoter and suppressor functions (13, 14). For Sema4D, this is reflected in its ability to inhibit ovarian carcinoma cell survival. Finally, receptors that associate in cis with plexins, such as Met and ErbB2, are known to alter Sema4D­mediated activities (3).

Source:
Recombinant protein corresponding to aa22-734 from human Semaphorin 4D Fc Chimera, CHO-derived.

Molecular Weight:
~110-135kD

Endotoxin:
<0.01EU/1ug (LAL method)

Storage and Stability:
Lyophilized and reconstituted products are stable for 6 months after receipt at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.