title: A protein kinase C-like activity involved in the chemotactic response of Dictyostelium discoideum.
abstract: During the developmental life cycle of the cellular slime mould Dictyostelium discoideum cells aggregate in response to pulses of extracellular cAMP. This chemotactic agent stimulates a number of signalling pathways in the cell including the activation of a phospholipase C activity leading to the transient generation of inositol 3,4,5-trisphosphate and diacylglycerol. The role of diacylglycerol in chemotactic response and development of Dictyostelium is not known. We have evidence to suggest that two protein kinase C-like enzymes exist in Dictyostelium due to the different cellular responses to two inhibitors specific for protein kinase C. One enzyme is preferentially sensitive to D-erythro-sphingosine, a diacylglycerol analogue, and is required for growth. A second is preferentially inhibited by bisindolylmaleimide GF109203X and is required for chemotaxis. We have identified protein kinase C-like kinase activity in Dictyostelium cell extracts which appears as the cells aggregate. This activity is stimulated by diacylglycerol, especially biologically relevant diacylglycerol species, and phosphorylates a peptide substrate which is an efficient substrate for mammalian protein kinase Cs. This activity is a candidate for the effector of diacylglycerol generated during the aggregative phase of Dictyostelium development and defines a role for diacylglycerol in the chemotactic response.
authors.affiliation: Department of Biochemistry, University of Oxford, UK.
authors.forename: P
authors.initials: P
authors.lastname: Phillips
authors.forename: M
authors.initials: M
authors.lastname: Thio
authors.forename: C
authors.initials: C
authors.lastname: Pears
mesh_terms: D000818:Animals; D002633:Chemotaxis; D004023:Dictyostelium / Q000502:physiology*; D004075:Diglycerides / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D004075:Diglycerides; D011493:Protein Kinase C