Phosphatidylinositol-4-phosphate 5-kinase regulates fission yeast cell integrity through a phospholipase C-mediated protein kinase C-independent pathway

Lu Deng, Reiko Sugiura, Kazuki Ohta, Kazuki Tada, Masahiro Suzuki, Masato Hirata, Shun Ichi Nakamura, Hisato Shuntoh, Takayoshi Kuno

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Fission yeast its3-1 mutant is an allele of the essential gene its3 + that encodes a phosphatidylinositol-4-phosphate 5-kinase (PIP5K) that produces phosphatidylinositol 4,5-bisphosphate. We found that the its3-1 mutant is sensitive to micafungin, a (1,3)-β-D-glucan synthase inhibitor, suggesting a cell wall integrity defect. Consistently, its3-1 mutation caused synthetic lethality with a (1,3)-β-D-glucan synthase mutant, bgs1-i2, and its3-1 mutant cells showed aberrant localization of green fluorescent protein-Bgs1. Similar aberrant localization of green fluorescent protein-tagged Rgf1, a putative phosphatidylinositol 4,5-bisphosphate-binding guanine nucleotide exchange factor for Rho protein, in its3-1 mutants was observed, suggesting a defective Rgf1/Rho pathway. To unravel the molecular mechanism(s), putative downstream components of PIP5K signaling were analyzed. Unexpectedly, overexpression of phospholipase C (Plc1), but not that of protein kinase C (PKC; Pck1 and Pck2), suppressed the phenotypes of the its3-1 mutant. These findings indicate that PKCs are not involved in the suppression, and further analysis revealed that PKCs are not downstream of Plc1 in fission yeast. Also, the enzymatic activity of Plc1 is essential for the suppression of the phenotypes and for the viability of the its3-1 mutant. These findings suggest that Its3 PIP5K regulates cell integrity through a Plc1-mediated PKC-independent pathway, in addition to the Rho/PKC pathway.

Original languageEnglish
Pages (from-to)27561-27568
Number of pages8
JournalJournal of Biological Chemistry
Volume280
Issue number30
DOIs
Publication statusPublished - Jul 29 2005

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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