Fig. 4.

Molecular interaction between thrombospondin1 (TSP1) and ADAMTS13. (A) To test for interactions between thrombospondin1 and ADAMTS13 in cells, we transfected 293A cells with cDNAs for thrombospondin1 and ADAMTS13, either singly or in combination.We immunoprecipitated ADAMTS13 using the Flag antibody from cell lysates and probed precipitated proteins by immunoblotting. Thrombospondin1 protein coprecipitated with ADAMTS13 only in cotransfected cells. (B) To test for interaction in vitro, we adsorbed ADAMTS13 or bovine serum albumin (BSA) to plastic dishes. Labeled thrombospondin1 was applied to dishes at increasing doses and then detected using a scanner. Dose-dependent binding was observed. Thrombospondin1 does not appreciably bind to BSA. These experiments were replicated twice.