A protein kinase C-like activity involved in the chemotactic response of Dictyostelium discoideum.
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.
Phillips
P
P
Department of Biochemistry, University of Oxford, UK.
Thio
M
M
Pears
C
C
D000818:Animals; D002633:Chemotaxis; D004023:Dictyostelium / Q000502:physiology*; D004075:Diglycerides / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*
D004075:Diglycerides; D011493:Protein Kinase C