title: Ceramide signals for initiation of yeast mating-specific cell cycle arrest.
abstract: Sphingolipids are major constituents of membranes. A number of S. cerevisiae sphingolipid intermediates such as long chains sphingoid bases (LCBs) and ceramides act as signaling molecules regulating cell cycle progression, adaptability to heat stress, and survival in response to starvation. Here we show that S. cerevisiae haploid cells must synthesize ceramide in order to induce mating specific cell cycle arrest. Cells devoid of sphingolipid biosynthesis or defective in ceramide synthesis are sterile and harbor defects in pheromone-induced MAP kinase-dependent transcription. Analyses of G1/S cyclin levels indicate that mutant cells cannot reduce Cln1/2 levels in response to pheromone. FACS analysis indicates a lack of ability to arrest. The addition of LCBs to sphingolipid deficient cells restores MAP kinase-dependent transcription, reduces cyclin levels, and allows for mating, as does the addition of a cell permeable ceramide to cells blocked at ceramide synthesis. Pharmacological studies using the inositolphosphorylceramide synthase inhibitor aureobasidin A indicate that the ability to synthesize and accumulate ceramide alone is sufficient for cell cycle arrest and mating. Studies indicate that ceramide also has a role in PI(4,5)P2 polarization during mating, an event necessary for initiating cell cycle arrest and mating itself. Moreover, our studies suggest a third role for ceramide in localizing the mating-specific Ste5 scaffold to the plasma membrane. Thus, ceramide plays a role 1) in pheromone-induced cell cycle arrest, 2) in activation of MAP kinase-dependent transcription, and 3) in PtdIns(4,5)P2 polarization. All three events are required for differentiation during yeast mating.
authors.affiliation: a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.|b Cato Research Ltd. , Durham , NC , USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Villasmil
authors.affiliation: a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.
authors.forename: Jamie
authors.initials: J
authors.lastname: Francisco
authors.affiliation: a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Gallo-Ebert
authors.affiliation: a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Donigan
authors.affiliation: a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.
authors.forename: Hsing-Yin
authors.initials: HY
authors.lastname: Liu
authors.affiliation: a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.|c Synthes, Inc , Paoli , PA , USA.
authors.forename: Melody
authors.initials: M
authors.lastname: Brower
authors.affiliation: a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Nickels
mesh_terms: D055574:Alkaline Ceramidase; D000581:Amidohydrolases / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D002518:Ceramides / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010675:Pheromones / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013107:Sphingolipids / Q000096:biosynthesis; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D002518:Ceramides; D016213:Cyclins; C100530:PIP2 protein, S cerevisiae; D010675:Pheromones; D029701:Saccharomyces cerevisiae Proteins; D013107:Sphingolipids; D014157:Transcription Factors; D010088:Oxidoreductases; C513563:LAC1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D000581:Amidohydrolases; C000588734:alkaline dihydroceramidase, S cerevisiae; D055574:Alkaline Ceramidase; C582674:YPC1 protein, S cerevisiae
keywords: cell cycle; ceramide; cyclin; lipid; yeast