cDNA cloning and characterization of vascular apoptosis-inducing protein 1

Hemorrhagic snake venom induces apoptosis in vascular endothelial cells (VE C). In previous reports, we described the purification from crude venom of Crotalus atrox of two vascular apoptosis-inducing proteins (VAP1 and VAP2) that specifically induce apoptosis in vascular endothelial cells. We report here the cDNA cloning and characterization of VAP1. VAP1 cDNA encoded a pr otein with 610 amino acid residues. The amino acid sequence predicted from the cDNA indicated that VAP1 belongs to the metalloprotease/disintegrin fam ily and that it is a multidomain polypeptide with a proprotein domain, a me talloprotease domain, a disintegrin-like domain, and a cysteine-rich domain . In the disintegrin-like domain, the sequence DECD replaces the RGD sequen ce that has frequently been found in such domains. We demonstrated that VAP 1 has Zn2+-dependent metalloprotease activity and degrades fibrinogen. Afte r incubation in the presence of either EDTA or EGTA, VAP1 was hardly able t o degrade fibrinogen and to induce apoptosis in VEC. Our results indicated that VAP1 is a new type of snake venom metalloprotease/disintegrin and sugg est that the metalloprotease activity of VAP1 might be involved in the indu ction of apoptosis by VAP1 in VEC. (C) 2000 Academic Press.