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PIK1, an essential phosphatidylinositol 4‐kinase associated with the yeast nucleus.
Author(s) -
GarciaBustos J.F.,
Marini F.,
Stevenson I.,
Frei C.,
Hall M.N.
Publication year - 1994
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1994.tb06519.x
Subject(s) - garcia , library science , biology , humanities , philosophy , computer science
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.