A MAP KINASE NECESSARY FOR RECEPTOR-MEDIATED ACTIVATION OF ADENYLYL-CYCLASE IN DICTYOSTELIUM

Analysis of a developmental mutant in Dictyostelium discoideum which i s unable to initiate morphogenesis has shown that a protein kinase of the MAP kinase/ERK family affects relay of the cAMP chemotactic signal and cell differentiation. Strains in which the locus encoding ERK2 is disrupted respond to a pulse of cAMP by synthesizing cGMP normally bu t show little synthesis of cAMP. Since mutant cells lacking ERK2 conta in normal levels of both the cytosolic regulator of adenylyl cyclase ( CRAC) and manganese-activatable adenylyl cyclase, it appears that this kinase is important for receptor-mediated activation of adenylyl cycl ase.