Yeast Cdc24p mutant lacking G protein β subunit binding

摘要

There is described a nucleic acid sequence encoding a section of Cdc24p (from Saccharomyces cerevisiae), a GEF, which does not substantially alter the interaction of this protein with the subunit of a hetero-trimeric G protein (G#). Mutant nucleic acid libraries and peptides of Cdc24p which alter the interaction of this GEF and G# are illustrated. The interruption of Cdc24p and G# prevents mating in yeasts but allows vegetative growth. The use of the products to screen for anti-fungal or anti-cancer agents is envisaged. Mutants of the G#, Ste4p, which prevent the interaction of G# and Cdc24p, are illustrated. The binding of the Far1 protein to Cdc24p is described. An assay is described in which the effect of human oncogenes proto-Dbl and Vav on S. cerevisiae with mating defects is assessed. A dbl peptide is also exemplified.