ADAMTS1/METH1 inhibits endothelial cell proliferation by direct binding and sequestration of VEGF₁₆₅

ADAMTS1 is a metalloprotease previously shown to inhibit angiogenesis in a variety of in vitro and in vivo assays. In the present study, we demonstrate that ADAMTS1 significantly blocks VEGFR2 phosphorylation with consequent suppression of endothelial cell proliferation. The effect on VEGFR2 function was due to direct binding and sequestration of VEGF₁₆₅ by ADAMTS1. Binding was confirmed by co-immunoprecipitation and cross-linking analysis. Inhibition of VEGF function was reversible, as active VEGF could be recovered from the complex. The interaction required the heparin-binding domain of the growth factor, because VEGF₁₂₁ failed to bind to ADAMTS1. Structure/function analysis with independent ADAMTS1 domains indicated that binding to VEGF₁₆₅ was mediated by the carboxyl-terminal (CT) region. ADAMTS1 and VEGF₁₆₅ were also found in association in tumor extracts. These findings provide a mechanism for the anti-angiogenic activity of ADAMTS1 and describe a novel modulator of VEGF bioavailability.