PACSIN2 is a regulator of the metalloprotease/disintegrin ADAM13

ADAM13 is a cell surface metalloprotease expressed in cephalic neural crest cells during early Xenopus development. The cytoplasmic domain of ADAM13 c ontains three potential SH3 (Src homology type 3) binding sites, suggesting that this region may support interactions with intracellular proteins. In this report we describe the identification, by a new strategy, of three pro teins that bind the ADAM13 cytoplasmic domain in vitro: X-Src1, X-An4, and X-PACSIN2. We focused our study on X-PACSIN2 protein because it colocalizes with ADAIM13 in migrating neural crest cells during embryonic development. Using pull-down experiments we show that X-PACSIN2 binds to ADAM13 in vitr o. Using Xenopus XTC cells, we demonstrate that ADAM13 and X-PACSIN2 coloca lize to membrane ruffles and cytoplasmic vesicles. We also show that X-PACS IN2 overexpression can rescue developmental alterations induced by overexpr ession of ADAM13, suggesting that both protein's interact in vivo. Finally, our results suggest that X-PACSIN2 overexpression reduces endogenous ADAM1 3 function while a truncated X-PACSIN2 (Delta SH3) increases this activity in cephalic neural crest cells. We propose that X-PACSIN2 may regulate ADAM 13 activity by influencing either its subcellular localization or its catal ytic activity. In agreement with this model, elimination of the ADAM13 cyto plasmic domain increased developmental alterations attributable to ADAM13 p roteolytic activity, (C) 2000 Academic Press.