Role of phospholipase C in Dictyostelium: formation of inositol 1,4,5-trisphosphate and normal development in cells lacking phospholipase C activity

EMBO J. 1994 Apr 1;13(7):1601-9.

Abstract

The micro-organism Dictyostelium uses extracellular cAMP to induce chemotaxis and cell differentiation. Signals are transduced via surface receptors, which activate G proteins, to effector enzymes. The deduced protein sequence of Dictyostelium discoideum phosphatidylinositol-specific phospholipase C (PLC) shows strong homology with the mammalian PLC-delta isoforms. To study the role of PLC in Dictyostelium, a plc- mutant was constructed by disruption of the PLC gene. No basal or stimulated PLC activity could be measured during the whole developmental programme of the plc- cells. Loss of PLC activity did not result in a visible alteration of growth or development. Further analysis showed that developmental gene regulation, cAMP-mediated chemotaxis and activation of guanylyl and adenylyl cyclase were normal. Although the cells lack PLC activity, inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] was present at only slightly lower concentrations compared with control cells. Mass analysis of inositol phosphates demonstrated the presence of a broad spectrum of inositol phosphates in Dictyostelium, which was unaltered in the plc- mutant. Cell labelling experiments with [3H]inositol indicated that [3H]Ins(1,4,5)P3 was formed in a different manner in the mutant than in control cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation
  • Chemotaxis / physiology*
  • Cyclic AMP / pharmacology
  • Dictyostelium / cytology
  • Dictyostelium / drug effects
  • Dictyostelium / physiology*
  • Dose-Response Relationship, Drug
  • Inositol 1,4,5-Trisphosphate / biosynthesis*
  • Inositol Phosphates / analysis
  • Mutation
  • Second Messenger Systems
  • Signal Transduction*
  • Type C Phospholipases / physiology*

Substances

  • Inositol Phosphates
  • Inositol 1,4,5-Trisphosphate
  • Cyclic AMP
  • Type C Phospholipases