title: Activation of Tsk and Btk tyrosine kinases by G protein beta gamma subunits.
abstract: Tsk/Itk and Btk are members of the pleckstrin-homology (PH) domain-containing tyrosine kinase family. The PH domain has been demonstrated to be able to interact with beta gamma subunits of heterotrimeric guanine nucleotide-binding proteins (G proteins) (G beta gamma) and phospholipids. Using cotransfection assays, we show here that the kinase activities of Tsk and Btk are stimulated by certain G beta gamma subunits. Furthermore, using an in vitro reconstitution assay with purified bovine brain G beta gamma subunits and the immunoprecipitated Tsk, we find that Tsk kinase activity is increased by G beta gamma subunits and another membrane factor(s). These results indicate that this family of tyrosine kinases could be an effector of heterotrimeric G proteins.
authors.affiliation: Department of Physiology, Cornell University Medical College, New York, NY 10021, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Langhans-Rajasekaran
authors.forename: Y
authors.initials: Y
authors.lastname: Wan
authors.forename: X Y
authors.initials: XY
authors.lastname: Huang
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D002451:Cell Compartmentation; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011487:Protein Conformation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C080813:emt protein-tyrosine kinase; D019204:GTP-Binding Proteins