Eukaryotic RAS proteins and yeast proteins with which they interact.

Abstract

Wild type Saccharomyces cerevisiae cells coordinate cell division with the availability of essential nutrients. In rich media, cells divide continuously. If the medium is moderately limited for some nutrients required for growth and division, cells grow slowly, requiring more time for each cell cycle. The increase in cell cycle time is due to a preferential increase in the time required to traverse the G1 phase of the cell cycle Johnston et al. 1977). If the medium is severely limited for nutrients, haploid cells arrest in G1 in an altered physiologic state. In this altered state, the cells are resistant to heat shock and can survive long periods of nutrient deprivation (Pringle and Hartwell 1981). Diploid cells severely limited for nutrients can arrest in G1 and sporulate (Esposito and Klapholz 1981). These data suggest that nutritional information may influence the nature of events in G1.