A developmentally regulated, putative serine/threonine protein kinase is essential for development in Dictyostelium

Mech Dev. 1991 Sep;35(2):89-101. doi: 10.1016/0925-4773(91)90060-j.

Abstract

Using PCR technology, we have cloned parts of three developmentally regulated putative serine/threonine kinases from Dictyostelium. All show significant homology to members of the cAMP-dependent protein kinase A/protein kinase C subfamilies. A genomic clone encoding one of these, DdPK3, has been isolated and sequenced. The open reading frame encodes a protein of 648 amino acids with the conserved kinase domain in the C-terminal half. The protein encoded by this gene is unusual in that it contains long homopolymer runs in the N-terminal half of the protein, including a long run of 88 amino acids in which 73 are glutamine residues. To examine the function of DdPK3, a gene disruption was created via homologous recombination. Ddpk3- cells do not aggregate by themselves but will co-aggregate with wild-type cells. However, after aggregation these cells are 'sloughed off' and do not proceed further through development, but are found as a discrete mass alongside the fruiting body formed by the wild-type cells. Analysis of signal transduction pathways indicates that cAMP pulse-induced expression of aggregation stage-specific genes is normal in Ddpk3- cells, as is induction of the prestalk gene Ddras in single cell assays. However, cAMP induction of the late promoters of cAMP receptor cAR1 and of two prespore-specific genes is absent under similar conditions. These cells show normal activation of adenylate cyclase and normal phosphorylation of the G alpha protein G alpha 2 in response to cAMP. The possible role of DdPK3 in Dictyostelium development is discussed.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Dictyostelium / enzymology
  • Dictyostelium / growth & development*
  • Fungal Proteins / metabolism*
  • Genes, Fungal
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Protein Kinases / physiology*
  • Protein-Serine-Threonine Kinases
  • Signal Transduction

Substances

  • Fungal Proteins
  • Protein Kinases
  • Protein-Serine-Threonine Kinases