Calcium indirectly regulates immunochemical reactivity and functional activities of the N-domain of thrombospondin-1.

ABSTRACT: Conformational changes induced in thrombospondin-1 by removal of calcium regulate interactions with some ligands of its N-modules. Because calcium binds primarily to elements of the C-terminal signature domain of thrombospondin-1, which are distant from the N-modules, such regulation was unexpected. To clarify the mechanism for this regulation, we compared ligand binding to the N-modules of thrombospondin-1 in the full-length protein and recombinant trimeric thrombospondin-1 truncated prior to the signature domain. Three monoclonal antibodies were identified that recognize the N-modules, two of which exhibit calcium-dependent binding to native thrombospondin-1 but not to the truncated trimeric protein. These antibodies or calcium selectively modulate interactions of fibronectin, heparin, s

SUBMITTER: Calzada MJ 

PROVIDER: S-EPMC2442560 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature