Molecular determinants of Xolloid action in vivo.

摘要: Xld (Xolloid) is a member of the Tolloid family metalloproteases found in embryos frog Xenopus laevis. It cleaves Chordin, an inhibitory binding protein for BMP2/4, releasing fragments with reduced affinity these important ventralizing signals. As consequence, increasing activity ventralizes embryos. We have used this phenotype as assay to determine requirement C-terminal, nonprotease component vivo activity. This part composed five complement C1r/C1s-sea urchin epidermal growth factor-BMP1 (CUB) and two factor domains, which are thought be involved protein-protein interactions may confer substrate specificity. Our results show that protease coupled CUB1 CUB2 minimum domain structure required ventralize block dorsal axis-inducing Chordin. Xld-CUB1-CUB2 protease-inactive version co-precipitates indicate first second CUB domains bind Chordin present it domain. Protease-inactive blocks cleavage by wild-type dorsalizes injected find does not share all C-terminal generate dorsalized phenotype.