Publisher Summary This chapter presents the methods used in the study of ScRheb in the yeast, S. cerevisiae, as well as those used to study mammalian Rheb. The chapter also describes methods used to address the C-terminal farnesylation of Rheb proteins and the requirement of this modification in Rheb function. Rheb (Ras homolog enriched in brain) is a new member of the Ras superfamily of G proteins that is highly conserved in a wide range of organisms. Homologs have been identified in human, rat, Saccharomyces cerevisiae, Schizosaccharomyces pombe, fruitfly, zebrafish, sea squirt, Botrvtis cinerea, and Candida albicans. Rheb shares some of the biological properties of Rap proteins, such as binding nonproductively to Raf-I and antagonizing Ras transformation: however, Rheb also has unique attributes. Rheb shows immediate-early gene characteristics. The Rheb transcript is increased in response to maximal electroconvulsive seizures as well as to N-methyl-D-aspartate (NMDA)-mediated synaptic activity and growth factors. In addition, the protein is farnesylated and the protein is localized to the plasma membrane.