PIK1, an essential phosphatidylinositol 4-kinase associated with the yeast nucleus

Jose F. Garcia-Bustos, Federica Marini, Isabelle Stevenson, Christian Frei, Michael N.hall

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102 Citations (Scopus)


Transmission of mitogenic and developmental signals to intracellular targets is often mediated by inositol derivatives. Here we present the cloning and characterization of a gene from Saccharomyces cerevisiae, PIK1, encoding the enzyme that catalyses the first committed step in the production of the second messenger inositol-1,4,5-trisphosphate. PIK1 encodes a phosphatidylinositol 4-kinase (PI 4-kinase) essential for growth. Cells carrying PIK1 on a multicopy vector overexpress PI 4-kinase activity exclusively in a nuclear fraction, suggesting that PIK1 is part of a nuclear phosphoinositide cycle. Temperature-sensitive mutations, but not a null mutation, can be suppressed by high osmolarity or an elevated concentration of Ca2+. Conditional mutants have a cytokinesis defect as indicated by a uniform terminal phenotype of cells with large buds and fully divided nuclei. We suggest that PIK1 controls cytokinesis through the actin cytoskeleton.

Original languageEnglish
Pages (from-to)2352-2361
Number of pages10
JournalThe EMBO Journal
Issue number10
Publication statusPublished - 7 Jun 1994
Externally publishedYes


  • Actin
  • Cytokinesis
  • Nucleus
  • PI 4-kinase
  • S. cerevisiae
  • Signal transduction

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