Dephosphorylation or antibody binding to the carboxy terminus stimulates pp60c-src.

摘要: Phosphorylation of pp60c-src at Tyr-527, six residues from the carboxy terminus, has been implicated in regulation protein-tyrosine kinase activity pp60c-src. Here we show that dephosphorylation by phosphatase treatment vitro caused a 10- to 20-fold increase activity. Binding specific antibody region which contains phosphotyrosine-527 also increased Each phosphorylation added substrates and Tyr-416 within similar mechanism involved altered interactions with ATP catalytic rate. We suggest phosphorylated terminus acts as an inhibitor protein domain pp60c-src, unless its conformation is either or binding. The additionally stimulated forms had reduced gel mobility, much like those reactions containing activated polyomavirus medium tumor antigen. These experiments provide models for activation cells transformed polyomavirus. autophosphorylation Tyr-527 occurs only very limited extent vitro, even when made available phosphatase. This suggests other kinases may normally phosphorylate regulate cell.