MUTANTS AFFECTED IN THE PUTATIVE DIACYLGLYCEROL BINDING-SITE OF YEASTPROTEIN-KINASE-C

In an attempt to study the functional similarities between protein kin ase C from the yeast Saccharomyces cerevisae and its human homologues me have started in vitro mutagenesis to alter specific domains, Here w e report on the exchange of four cysteine residues by serines in yeast Pkc1p that have been shown to be essential for diacylglycerol (DAG:) binding and activation by this compound in humans, The mutant yeast pr otein leads to sensitivity to caffeine and low concentrations of SDS w hen expressed in a pkc1 deletion strain. However, sensitivity to staur osporine was not affected. Our data indicate that the conserved DAG bi nding domain serves an important function in yeast Pkc1p. (C) 1997 Fed eration of European Biochemical Societies.