Protein and phospholipid methylation during chemotaxis in Dictyostelium discoideum and its relationship to calcium movements

Abstract

Suspensions of cyclic AMP sensitive cells of Dictyostelium discoideum responded to a cyclic AMP pulse with increased methylation of a protein of molecular weight about 120,000 and increased phospholipid demethylation. Protein methylation reached its peak 15-30 sec after cyclic AMP addition. Phospholipid demethylation reached its maximum within 2 min and basal levels were recovered in 3 min. S-Adenosyl-L-methionine is probably the methyl donor. In vitro addition of 0.25 mM and 25 microM S-adenosyl-L-methionine to sonicated D. discoideum cells inhibited ATP-dependent 45Ca2+ uptake by 70% and 25%, respectively. Based on these lines of evidence we propose that protein and phospholipid methylation are involved in D. discoideum chemotaxis probably by regulation of intracellular Ca2+ movements.