title: Mapping of the novel protein kinase catalytic domain of Dictyostelium myosin II heavy chain kinase A.
abstract: Myosin heavy chain kinase A (MHCK A) in Dictyostelium was identified as a biochemical activity that phosphorylates threonine residues in the myosin II tail domain and regulates myosin filament assembly. The catalytic domain of MHCK A has now been mapped through the functional characterization of a series of MHCK A truncation mutants expressed in Escherichia coli. A recombinant protein comprising the central nonrepetitive domain of MHCK A (residues 552-841) was isolated in a soluble form and shown to phosphorylate Dictyostelium myosin II, myelin basic protein, and a synthetic peptide substrate. The functionally mapped catalytic domain of MHCK A shows no detectable sequence similarity to known classes of eukaryotic protein kinases but shares substantial sequence similarity with a transcribed Caenorhabditis elegans gene and with the mammalian elongation factor-2 kinase (calcium/calmodulin-dependent protein kinase III). We suggest that MHCK A represents the prototype for a novel, widely occurring protein kinase family.
authors.affiliation: Department of Biochemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada.
authors.forename: G P
authors.initials: GP
authors.lastname: Côté
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.forename: M B
authors.initials: MB
authors.lastname: Murphy
authors.forename: T T
authors.initials: TT
authors.lastname: Egelhoff
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004023:Dictyostelium; D004926:Escherichia coli; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D011494:Protein Kinases / Q000235:genetics*; D015800:Protozoan Proteins; D011994:Recombinant Proteins / Q000235:genetics; D016415:Sequence Alignment; D017421:Sequence Analysis
chemical_list: D015800:Protozoan Proteins; D011994:Recombinant Proteins; D011494:Protein Kinases; C093485:110 kDa protein kinase, Dictyostelium