TEM8 (H-140) Antibody: sc-15406

ATR/TEM8 Background Information
The tripartite toxin secreted by Bacillus anthraci is the causative agent of anthrax evading the immune system and killing the host during a systemic infection. Two components of the toxin, odemema factor (OF) and lethal factor (LF) enzymatically modify substrates within the cytosol of mammalian cells. The third component, protective antigen (PA), binds to a cellular receptor, designated ATR (anthrax toxin receptor), which mediates the delivery of the enzymatic components to the cytosol. TEM8 (tumor endothelial marker 8) is one of the tumor specific endothelial markers (TEMs) whose N-terminus encodes ATR. TEM8 is highly expressed in tumor endothelial cells but not in normal endothelial cells. TEMs have elevated expression during tumor angiogenesis. Four TEM genes, TEM1, TEM5, TEM7 and TEM8, encode the TEM proteins, which contain putative transmembrane domains. ATR is a type I membrane protein with an extracellular von Willebrand factor A domain that binds directly to PA. The first 364 amino acids of ATR protein are identical to those of TEM8. However, the C-terminal ends of the ATR and TEM8 proteins are different, presumably due to alternative splicing. A soluble version of von Willebrand factor A domain seems to protect cells from the toxin action.