Schizosaccharomyces pombe Vps34p, a phosphatidylinositol-specific PI 3-kinase essential for normal cell growth and vacuole morphology

Kaoru Takegawa, Daryll B. DeWald, Scott D. Emr

Research output: Contribution to journalArticle

76 Citations (Scopus)

Abstract

We have cloned the gene, vps34+, from the fission yeast Schizosaccharomyces pombe which encodes an 801 amino acid protein with phosphatidylinositol 3-kinase activity. The S. pombe Vps34 protein shares 43% amino acid sequence identity with the Saccharomyces cerevisiae Vps34 protein and 28% identity with the p110 catalytic subunit of the mammalian phosphatidylinositol 3-kinase. When the vps34+ gene is disrupted, S. pombe strains are temperature-sensitive for growth and the mutant cells contain enlarged vacuoles. Furthermore, while wild-type strains exhibit substantial levels of phosphatidylinositol 3-kinase activity, this activity is not detected in the vps34Δ strain. S. pombe Vps34p-specific antiserum detects a single protein in cells of ~90 Kda that fractionates almost exclusively with the crude membrane fraction. Phosphatidylinositol 3-kinase activity also is localized mainly in the membrane fraction of wild-type cells. Immunoisolated Vps34p specifically phosphorylates phosphatidylinositol on the D-3 position of the inositol ring to yield phosphatidylinositol(3)phosphate, but does not utilize phosphatidylinositol(4)phosphate or phosphatidylinositol(4,5)bisphosphate as substrates. In addition, when compared to the mammalian p110 phosphatidylinositol 3-kinase, S. pombe Vps34p is relatively insensitive to the inhibitors wortmannin and LY294002. Together, these results indicate that S. pombe Vps34 is more similar to the phosphatidylinositol-specific 3-kinase, Vps34p from S. cerevisiae, and is distinct from the p110/p85 and G protein-coupled phosphatidylinositol 3-kinases from mammalian cells. These data are discussed in relation to the possible role of Vps34p in vesicle-mediated protein sorting to the S. pombe vacuole.

Original languageEnglish
Pages (from-to)3745-3756
Number of pages12
JournalJournal of cell science
Volume108
Issue number12
Publication statusPublished - Dec 1 1995
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Cell Biology

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