Sphingosine-1-phosphate is a sphingolipid metabolite involved in the regulation of cell proliferation in mammalian cells. The major route of sphingosine-1-phosphate degradation is through cleavage at the C, bond by sphingosine phosphate lyase. The recent identification of the first dihydrosphingosine/sphingosine phosphate lyase gene in Saccharomyces cerevisiae establishes that phosphorylated sphingoid base metabolism is conserved throughout evolution. The dpl1delta deletion mutant, which accumulates endogenous phosphorylated sphingoid bases, exhibits unregulated proliferation upon approach to stationary phase. The increased proliferation rate during respiratory growth was associated with failure to appropriately recruit cells into the G1 phase of the cell cycle. Several genes were found to be overexpressed or prematurely expressed during nutrient deprivation in the dpl1delta strain, including glucose-repressible genes and G1 cyclins. These studies implicate a role for DPL1 and phosphorylated sphingoid bases in the regulation of global responses to nutrient deprivation in yeast.