TOR1 and TOR2 are structurally and functionally similar but not identical phosphatidylinositol kinase homologues in yeast

S. B. Helliwell, P. Wagner, J. Kunz, M. Deuter-Reinhard, R. Henriquez, M. N. Hall

Research output: Contribution to journalArticle

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Abstract

The Saccharomyces cerevisiae genes TOR1 and TOR2 were originally identified by mutations that confer resistance to the immunosuppressant rapamycin. TOR2 was previously shown to encode an essential 282-kDa phosphatidylinositol kinase (PI kinase) homologue. The TOR1 gene product is also a large (281 kDa) PI kinase homologue, with 67% identity to TOR2. TOR1 is not essential, but a TOR1 TOR2 double disruption uniquely confers a cell cycle (G1) arrest as does exposure to rapamycin; disruption of TOR2 alone is lethal but does not cause a cell cycle arrest. TOR1-TOR2 and TOR2-TOR1 hybrids indicate that carboxy-terminal domains of TOR1 and TOR2 containing a lipid kinase sequence motif are interchangeable and therefore functionally equivalent; the other portions of TOR1 and TOR2 are not interchangeable. The TOR1-1 and TOR2-1 mutations, which confer rapamycin resistance, alter the same potential protein kinase C site in the respective protein's lipid kinase domain. Thus, TOR1 and TOR2 are likely similar but not identical, rapamycin- sensitive PI kinases possibly regulated by phosphorylation. TOR1 and TOR2 may be components of a novel signal transduction pathway controlling progression through G1.

Original languageEnglish
Pages (from-to)105-118
Number of pages14
JournalMolecular Biology of the Cell
Volume5
Issue number1
Publication statusPublished - 1994
Externally publishedYes

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Sirolimus
Phosphatidylinositols
Phosphotransferases
Yeasts
G1 Phase Cell Cycle Checkpoints
Lipids
Mutation
Immunosuppressive Agents
Cell Cycle Checkpoints
Protein Kinases
Protein Kinase C
Genes
Saccharomyces cerevisiae
Signal Transduction
Phosphorylation

ASJC Scopus subject areas

  • Cell Biology
  • Genetics
  • Molecular Biology

Cite this

Helliwell, S. B., Wagner, P., Kunz, J., Deuter-Reinhard, M., Henriquez, R., & Hall, M. N. (1994). TOR1 and TOR2 are structurally and functionally similar but not identical phosphatidylinositol kinase homologues in yeast. Molecular Biology of the Cell, 5(1), 105-118.

TOR1 and TOR2 are structurally and functionally similar but not identical phosphatidylinositol kinase homologues in yeast. / Helliwell, S. B.; Wagner, P.; Kunz, J.; Deuter-Reinhard, M.; Henriquez, R.; Hall, M. N.

In: Molecular Biology of the Cell, Vol. 5, No. 1, 1994, p. 105-118.

Research output: Contribution to journalArticle

Helliwell, SB, Wagner, P, Kunz, J, Deuter-Reinhard, M, Henriquez, R & Hall, MN 1994, 'TOR1 and TOR2 are structurally and functionally similar but not identical phosphatidylinositol kinase homologues in yeast', Molecular Biology of the Cell, vol. 5, no. 1, pp. 105-118.
Helliwell, S. B. ; Wagner, P. ; Kunz, J. ; Deuter-Reinhard, M. ; Henriquez, R. ; Hall, M. N. / TOR1 and TOR2 are structurally and functionally similar but not identical phosphatidylinositol kinase homologues in yeast. In: Molecular Biology of the Cell. 1994 ; Vol. 5, No. 1. pp. 105-118.
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