Beschreibung:
<jats:p>A tail fragment of <jats:italic>Dictyostelium discoideum</jats:italic> 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 <jats:italic>D.discoideum</jats:italic> 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.</jats:p>