Analysis of the sites in p56lck whose phosphorylation is induced by tetradecanoyl phorbol acetate.
p56lck is a member of the src family of tyrosine kinases that is expressed almost exclusively in lymphocytes. Previous studies have shown that treatment of T cells with activators of protein kinase C induces serine phosphorylation of p56lck. We show here that treatment of Jurkat cells with 12-O-tetradecanoyl phorbol-13-acetate also induces threonine phosphorylation of p56lck. Chymotryptic mapping shows that at least three sites in p56lck undergo phosphorylation in TPA-treated Jurkat cells. Cyanogen bromide cleavage analysis demonstrates that these new phosphorylation sites are located in an amino-terminal 32 kDa fragment containing amino acid residues 14-261.
Luo
K X
KX
Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92138.
Sefton
B M
BM
D002460:Cell Line; D002918:Chymotrypsin / Q000494:pharmacology; D003488:Cyanogen Bromide / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D015458:Leukemia, T-Cell / Q000473:pathology; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D010449:Peptide Mapping; D010748:Phosphopeptides / Q000032:analysis; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000502:physiology; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D010748:Phosphopeptides; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D012697:Serine Endopeptidases; D002918:Chymotrypsin; C028344:glutamyl endopeptidase; D013755:Tetradecanoylphorbol Acetate; D003488:Cyanogen Bromide