5] In vivo assays for farnesyltransferase inhibitors with Saccharomyces cereuisiae

Abstract

Publisher Summary This chapter describes simple plate assays for farnesyltransferase inhibitors using yeast gpal and RAS2Val-9 mutants. The methods are useful in screening natural products for inhibitors and in evaluating synthetic inhibitors. Protein farnesylation is important for protein function. The modification is catalyzed by farnesyltransferase, which transfers a farnesyl group from farnesyl diphosphate to a cysteine residue located in a carboxyl-terminal tetrapeptide sequence (the CaaX motif) of an acceptor protein. Farnesylated proteins include Ras proteins, nuclear lamins, the γ subunits of transducin and yeast heterotrimeric G protein, and fungal mating pheromones. Farnesyltransferase inhibitors provide valuable tools for the understanding of the catalytic mechanism of the enzyme. The assays are used to evaluate synthetic inhibitors such as peptidomimetics because the yeast system provides simple in vivo assays. It is possible that the effects of inhibitors are different between the yeast and mammalian enzymes and that the penetration and degradation of inhibitors are different between yeast and mammalian cells.