The MET tyrosine kinase is the hepatocyte growth factor/scatter factor (HGF/SF) receptor, which elicits multiple biological responses in epithelial cells, including cell survival. We previously demonstrated that in stress conditions, the MET receptor is cleaved by caspases within its juxtamembrane region, generating a pro-apoptotic intracellular fragment of 40 kDa. The caspase cleavage site at aspartic acid D1000 is adjacent to tyrosine Y1001, which when phosphorylated upon MET activation, is involved in CBL recruitment, allowing receptor ubiquitination and down regulation. Scanning mutagenesis of the MET juxtamembrane region led us to demonstrate that V999 and D1000 are essential for the caspase cleavage, while D1000 and Y1001 are essential for CBL recruitment. By examining whether overlapping of these sites leads to a functional interference, an inverse relationship was found between generation of p40 MET and phosphorylation of MET, with a direct involvement of phosphorylated Y1001 in protecting MET against its caspase cleavage. A molecular modeling analysis of caspase 3 interaction with the juxtamembrane region of MET confirmed that phosphorylation of this tyrosine is not compatible with its recognition by active caspase 3. These data demonstrate a direct protection mechanism of an activated phosphorylated MET receptor, against its caspase-dependent cleavage.
We have not found any resources mentioned in this publication.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to SciCrunch, however this is not currently a free service.