Investigation of factors that influence phosphorylation of pp60c-src on tyrosine 527.
Phosphorylation at tyrosine 527 of the proto-oncogene product, pp60c-src, has been proposed to decrease the tyrosine kinase activity of the enzyme. We have investigated potential factors that might influence phosphorylation at this site by making mutant variants of the pp60c-src protein. By effectively eliminating the site of N-terminal myristylation, we demonstrated that stable membrane association is not necessary for tyrosine 527 phosphorylation. Furthermore, mutational elimination of the enzymatic activity of this mutant pp60c-src protein did not alter the efficiency of phosphorylation at tyrosine 527. These data are consistent with the proposal that pp60c-src may be phosphorylated at tyrosine 527 by a cellular tyrosine kinase distinct from pp60c-src. In addition, using detergent-permeabilized cells, we established conditions that allow efficient phosphorylation of tyrosine 527 in vitro.
Schuh
S M
SM
Department of Microbiology, State University of New York, Stony Brook 11794.
Brugge
J S
JS
D000936:Antigen-Antibody Complex / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D009154:Mutation; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D010449:Peptide Mapping; D010766:Phosphorylation; D010957:Plasmids; D011494:Protein Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src); D012333:RNA, Messenger / Q000096:biosynthesis; D014443:Tyrosine / Q000378:metabolism*
D000936:Antigen-Antibody Complex; D009227:Myristic Acids; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D019814:Myristic Acid; D014443:Tyrosine; D011494:Protein Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)