Ras Family G-Proteins in Saccharomyces Cerevisiae and Schizosaccharomyces Pombe

Abstract

The Ras superfamily G proteins are signaling proteins that regulate a variety of physiological events within the cell. The superfamily consists of distinct subfamilies including the Ras, Rho, Rab, ARF, Ran, and Rheb branches. Much of what is known about these subfamilies has come from work done in the simple unicellular eukaryotes, Saccha-romyces cerevisiae and Schizosaccharomyces pombe. Using homologous proteins found in these yeasts, clues as to their physiological function in higher eukaryotic systems have been deduced. In addition, an understanding of how these proteins are regulated has also been obtained from yeast studies. This chapter will focus on the Ras super-family G-proteins in yeast; more specifically on Ras and Rheb from both yeasts, as well as Rsr1/Bud1 of S. cerevisiae. Their physiological functions as well as modes of regulation with be addressed