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The protein kinase activity associated with pp60src, the transforming protein of Rous sarcoma virus, was found to phosphorylate tyrosine when assayed in an immunoprecipitate. Despite the fact that a protein kinase with this activity has not been described before, several observations suggest that pp60src also phosphorylates tyrosine in vivo. First, chicken(More)
The largest subunit of RNA polymerase II contains a unique C-terminal domain (CTD) consisting of tandem repeats of the consensus heptapeptide sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Two forms of the largest subunit can be separated by SDS-polyacrylamide gel electrophoresis. The faster migrating form termed IIA contains little or no phosphate on the(More)
Immobilon, a membrane of polyvinylidene difluoride to which gel-fractionated proteins can be transferred electrophoretically, was found to be an excellent matrix for the analysis of the phosphoamino acid content of phosphoproteins. Hydrolysis of 32P-labeled proteins bound to Immobilon with 5.7 N HCl resulted in the release of 90% of the 32P in the form of(More)
We have found that the transfer of gel-fractionated proteins to membranes facilitates phosphopeptide mapping. Nitrocellulose proves to be an excellent matrix for both cyanogen bromide cleavage and proteolytic digestion. Digestion of p56lck bound to a nitrocellulose membrane with cyanogen bromide or trypsin generated patterns of phosphopeptides(More)
Vinculin, a protein associated with the cytoplasmic face of the focal adhesion plaques which anchor actin-containing microfilaments to the plasma membrane and attach a cell to the substratum, contains 8-fold more phosphotyrosine in cells transformed by Rous sarcoma virus than in uninfected cells. Because the transforming protein of RSV, p60src, is a protein(More)
Antisera were raised against a synthetic peptide (src-c) containing the six COOH-terminal amino acids of p60src, the transforming protein of Rous sarcoma virus (RSV). Antibodies specific for the src-c peptide were purified by affinity chromatography and then used to study the location of p60src in transformed cells. The distribution of p60src was compared(More)
The CD4 lymphocyte surface glycoprotein and the lck tyrosine protein kinase p56lck are found as a complex in T lymphocytes. We have defined the domains in both proteins that are responsible for this interaction by coexpressing hybrid and deleted forms of the two proteins in HeLa cells. We have found that the unique 32 amino-terminal residues of p56lck and(More)
Incubation of quiescent chicken embryo cells with platelet-derived growth factor, epidermal growth factor, or serum was found to stimulate phosphorylation of two proteins of ca. 42,000 daltons on tyrosine. These proteins are structurally related to each other and to two proteins phosphorylated on tyrosine under similar conditions in mitogen-treated mouse(More)