title: Activation of myosin-I by members of the Ste20p protein kinase family.
abstract: The heavy chain of myosin-ID isolated from Dictyostelium was identified as an in vitro substrate for members of the Ste20p family of serine/threonine protein kinases which are thought to regulate conserved mitogen-activated protein kinase pathways. Yeast Ste20p and Cla4p and mammalian p21-activated protein kinase (PAK) phosphorylated the heavy chain to 0.5-0.6 mol of Pi/mol and stimulated the actin-dependent Mg2+-ATPase activity to an extent equivalent to that of the Ste20p-like myosin-I heavy chain kinase isolated from Dictyostelium. PAK purified from rat brain required GTPgammaS-Cdc42 to express full activity, whereas recombinant mouse mPAK3 fused to glutathione S-transferase and purified from bacteria, and Ste20p and Cla4p purified from yeast extracts were fully active without GTPgammaS-Cdc42. These results suggest, together with the high degree of structural and functional conservation of Ste20p family members and myosin-I isoforms, that myosin-I activation by Ste20p family protein kinases may contribute to the regulation of morphogenetic processes in organisms ranging from yeast to mammalian cells.
authors.affiliation: Eukaryotic Genetics Group, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec H4P 2R2, Canada. EKKEHARD.LEBERER@NRC.CA
authors.forename: C
authors.initials: C
authors.lastname: Wu
authors.forename: S F
authors.initials: SF
authors.lastname: Lee
authors.forename: E
authors.initials: E
authors.lastname: Furmaniak-Kazmierczak
authors.forename: G P
authors.initials: GP
authors.lastname: Côté
authors.forename: D Y
authors.initials: DY
authors.lastname: Thomas
authors.forename: E
authors.initials: E
authors.lastname: Leberer
mesh_terms: D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D004023:Dictyostelium; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D008954:Models, Biological; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D029701:Saccharomyces cerevisiae Proteins; D054462:p21-Activated Kinases
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C095212:CLA4 protein, S cerevisiae; C515912:Pak3 protein, mouse; C515913:Pak3 protein, rat; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; C078754:STE20 protein, S cerevisiae; D017301:Ca(2+) Mg(2+)-ATPase; D019204:GTP-Binding Proteins; D009218:Myosins