Phosphorylation of threonine residues on cloned fragments of the Dictyostelium myosin heavy chain.
A tail fragment of Dictyostelium discoideum myosin has been cloned and expressed as a fusion protein with the N-terminal region of MS-2 polymerase. The cloned fragment was phosphorylated with myosin heavy chain kinase II from aggregation-competent D. discoideum cells that specifically phosphorylate threonine residues on the myosin tail. Phosphopeptide maps showed the same site specificity of phosphorylation with the fusion protein as a substrate as with native myosin. An improved assay for the kinase was developed in which the fusion protein is precipitated with a monoclonal antibody that inhibits polymerization of the myosin tails without preventing their phosphorylation. Sites of phosphorylation were tentatively localized to a sequence in the C-terminal region of the heavy chain where four threonine residues are found.
Wagle
G
G
Max-Planck-Institut für Biochemie, Martinsried, FRG.
Noegel
A
A
Scheel
J
J
Gerisch
G
G
D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004023:Dictyostelium / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007163:Immunosorbent Techniques; D008970:Molecular Weight; D009218:Myosins / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism*; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism*; D013912:Threonine / Q000031:analogs & derivatives*
D010446:Peptide Fragments; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D010769:Phosphothreonine; D013912:Threonine; D010770:Phosphotransferases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C033142:myosin-heavy-chain kinase; D009218:Myosins