title: p56lck phosphorylation by Ca2+/calmodulin-dependent protein kinase type II.
abstract: Ca2+/calmodulin-dependent protein kinases are implicated in regulating the Ca2+ signaling involved in T cell activation and in thymocyte selection. One of the earliest events in signaling through the T cell antigen receptor is activation of the protein tyrosine kinase p56lck. Following T cell activation or signaling through the IL-2 receptor, Ca(2+)-mediated phosphorylation of p56lck occurs on serine/threonine residues. Isoforms of the multifunctional Ca2+/calmodulin-dependent protein kinases, CaM kinase-II and CaM kinase-Gr are found in human T lymphocytes. CaM kinase-II, but not CaM kinase-Gr, phosphorylates the T cell tyrosine kinase p56lck in vitro. Tryptic phosphopeptide maps indicate that CaM kinase-II phosphorylates p56lck on multiple sites in vitro. Kinase assays of p56lck modified by CaM kinase-II indicate that CaM kinase-II modification does not appreciably affect p56lck phosphotransfer activity.
authors.affiliation: Wellcome Research Laboratories, Research Triangle Park, NC 27709.
authors.forename: M M
authors.initials: MM
authors.lastname: Bland
authors.forename: O B
authors.initials: OB
authors.lastname: McDonald
authors.forename: A C
authors.initials: AC
authors.lastname: Carrera
mesh_terms: D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D004533:Egtazic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D008297:Male; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D016548:Prosencephalon / Q000201:enzymology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000201:enzymology*
chemical_list: D010748:Phosphopeptides; D004533:Egtazic Acid; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D017871:Calcium-Calmodulin-Dependent Protein Kinases