Phosphotyrosine‐containing proteins in Dictyostelium discoideum

Abstract
Phosphotyrosine‐containing proteins in Dictyostelium discoideum were detected by immunoblot analysis and inununoprecipitation using a monoclonal anti‐phosphotyrosine antibody. The iodinated antibody recognized on bots a cluster of 205–220 kDa polypeptides and bands of 107 and 60 kDa. The 107 and 60 kDa polypeptides and, in addition, a 82 kDa one became phosphorylated on tyrosine when the immunoprecipitate was incubated with [γ‐32p]ATP. In preparations from differentiating cells the intensity of the label was increased in the 60 kDa band and decreased in the 107 and 205–220 kDa bands.