RHO gene products, putative small GTP‐binding proteins, are importnat for activation of the CAL1/CDC43 gene product, a protein geranylgeranyltransferase in Saccharomyces cerevisiae

Two multicopy suppressors of the call‐1 mutation in the yeast Saccharomyces cerevisiae have been isolated and characterized. They are identical to the yeast RHO1 and RHO2 genes, which encode putative small GTP‐binding proteins. Multiple copies of either RHO gene suppressed temperature‐sensitive growth of the call‐1 mutant but did not suppress the call null mutant. Genetic analysis suggests that overproduction of either RHO gene product acts for activation of the CAL1 gene product.