title: Cloning and characterization of a novel Cdc42-associated tyrosine kinase, ACK-2, from bovine brain.
abstract: Cdc42 plays an important role in intracellular signaling pathways that influence cell morphology and motility and stimulate DNA synthesis. In attempts to determine whether nonreceptor tyrosine kinases play a fundamental role in Cdc42 signaling, we have cloned and biochemically characterized a new Cdc42-associated tyrosine kinase (ACK) from bovine brain. This tyrosine kinase, named ACK-2, has a calculated molecular mass of 83 kDa and shares a number of primary structural domains with the 120-kDa ACK (ACK-1). The main differences between the primary structures of ACK-2 and ACK-1 occur in the amino- and carboxyl-terminal regions. Like ACK-1, ACK-2 binds exclusively to activated (GTP-bound) Cdc42 and does not bind to its closest homologs, e.g. activated Rac. ACK-2 could not be activated by addition of glutathione S-transferase (GST)-Cdc42(Q61L), a GTPase-defective mutant, or by GTPgammaS-loaded GST-Cdc42 in in vitro kinase assays. However, ACK-2 was activated when cotransfected with wild type Cdc42 or Cdc42(Q61L) and stably associated with Cdc42(Q61L) in vivo, indicating that ACK-2 interacts with active Cdc42 in cells. Furthermore, the tyrosine kinase activity of ACK-2 was stimulated both by epidermal growth factor and bradykinin, suggesting that ACK-2 may play a role in the signaling actions of both receptor tyrosine kinases or heterotrimeric G-protein-coupled receptors.
authors.affiliation: Department of Pharmacology, Cornell University, Ithaca, New York 14853-6401, USA.
authors.forename: W
authors.initials: W
authors.lastname: Yang
authors.forename: R A
authors.initials: RA
authors.lastname: Cerione
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001920:Bradykinin / Q000494:pharmacology; D001921:Brain / Q000201:enzymology*; D019556:COS Cells; D002417:Cattle; D002448:Cell Adhesion; D018797:Cell Cycle Proteins / Q000378:metabolism*; D003001:Cloning, Molecular; D017931:DNA Primers; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae
chemical_list: D018797:Cell Cycle Proteins; D017931:DNA Primers; D011994:Recombinant Proteins; D004815:Epidermal Growth Factor; D011505:Protein-Tyrosine Kinases; D019204:GTP-Binding Proteins; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae; D001920:Bradykinin