Premium
Polyoma middle‐sized T antigen can be phosphorylated on tyrosine at multiple sites in vitro.
Author(s) -
Hunter T.,
Hutchinson M.A.,
Eckhart W.
Publication year - 1984
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1984.tb01763.x
Subject(s) - antigen , phosphorylation , biology , microbiology and biotechnology , in vitro , tyrosine , biochemistry , genetics
The polyoma middle‐sized T antigen (MT antigen) is associated with a protein kinase activity which phosphorylates tyrosine residues in polyoma T antigens in vitro. We have studied the sites of tyrosine phosphorylation of MT antigens phosphorylated in immunoprecipitates or in soluble form after partial purification by immunoaffinity chromatography. By analyzing the amino acid sequences of tryptic peptides of MT antigen, and by analyzing deletion mutant MT antigens, we have identified two major sites of phosphorylation in MT antigen, tyrosines 250 and 315. Additional sites were phosphorylated under some conditions. A synthetic peptide (Glu.Glu.Glu.Glu.Tyr.Met.Pro.Met.Glu), corresponding to the sequence around tyrosine 315, was phosphorylated when added to immunoprecipitates containing MT antigen.