| Title: | Phosphatidylinositol 3-phosphate 5-kinase is required for the cellular response to nutritional starvation and mating pheromone signals in Schizosaccharomyces pombe |
| Author(s): | Morishita M; Morimoto F; Kitamura K; Koga T; Fukui Y; Maekawa H; Yamashita I; Shimoda C; |
| Address: | "Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan" |
| DOI: | 10.1046/j.1356-9597.2001.00510.x |
| ISSN/ISBN: | 1356-9597 (Print) 1356-9597 (Linking) |
| Abstract: | "BACKGROUND: Phosphatidylinositol (3,5) bisphosphate, which is converted from phosphatidylinositol 3-phosphate by phosphatidylinositol 3-phosphate 5-kinase, is implicated in vacuolar functions and the sorting of cell surface proteins within endosomes in the endocytic pathway of budding yeast. A homologous protein, SpFab1p, has been found in the fission yeast Schizosaccharomyces pombe, but its role is not known. RESULTS: Here we report that SpFab1p is encoded by ste12+ known as a fertility gene in S. pombe. The ste12 mutant grew normally under stress-free conditions, but was highly vacuolated and swelled at high temperatures and under starvation conditions. In nitrogen-free medium, ste12 cells were arrested in G1 phase, but partially defective in the expression of genes responsible for mating and meiosis. The ste12 mutant was defective both in the production of, and in the response to, mating pheromones. The amount of the pheromone receptor protein Map3p, was substantially decreased in ste12 cells. Map3p was transported to the cell surface, then internalized and eventually transported to the vacuolar lumen, even in the ste12 mutant. CONCLUSION: The results indicate that phosphatidylinositol(3,5)bisphosphate is essential for cellular responses to various stresses and for the mating pheromone signalling under starvation conditions" |
| Keywords: | Amino Acid Sequence Culture Media Fungal Proteins/genetics Meiosis/physiology Molecular Sequence Data Mutation Phosphotransferases (Alcohol Group Acceptor)/*physiology *Saccharomyces cerevisiae Proteins Schizosaccharomyces/*metabolism/physiology Sequence; |
| Notes: | "MedlineMorishita, Masayo Morimoto, Fusako Kitamura, Kenji Koga, Takako Fukui, Yasuhisa Maekawa, Hiromi Yamashita, Ichiro Shimoda, Chikashi eng Research Support, Non-U.S. Gov't England 2002/03/16 Genes Cells. 2002 Feb; 7(2):199-215. doi: 10.1046/j.1356-9597.2001.00510.x" |
