Inportance of Phosphatidylinositol 3-Phosphate in Sporulation of Schizosaccharomyces pombe

抄録

  In Schizosaccharomyces pombe, Pik3p phosphorylates phosphatidylinositol (PI) to produce PI 3-P, which is further phosphorylated by Ste12p to yield PI 3,5-P₂. Pik3p is required for both conjugation and sporulation. To test which of PI 3-P and PI 3,5-P₂ is required for sporulation, diploid cells defective in production of PI 3,5-P₂ were used. They underwent sporulation almost normally provided that the osmotic pressure of the medium was controlled, suggesting that not PI 3,5-P₂ but PI 3-P was important. Electron microscopic analysis confirmed normal sporulation in the absence of PI 3,5-P₂ although the forespore membrane was found to be less dense in these cells.