These effects include regulation of endocytosis , ubiquitin-dependent proteolysis (and, thus, regulation of nutrient uptake [ 24 ] ), cytoskeletal dynamics, the cell cycle , translation , posttranslational protein modification, and the heat stress response. [ 25 ] Additionally, modulation of sphingolipid metabolism by phosphatidylinositol (4,5)-bisphosphate signaling via Slm1p and Slm2p