Molecular Genetics and Genomics

, Volume 267, Issue 3, pp 313–320

Phospholipase C interacts with Sgd1p and is required for expression of GPD1 and osmoresistance in Saccharomyces cerevisiae

  •  H. Lin
  •  P. Nguyen
  •  A. Vancura
Original Paper

Abstract.

The Saccharomyces cerevisiae PLC1 gene encodes a homolog of the δ isoform of mammalian phosphoinositide-specific phospholipase C. Cells deleted for PLC1 (plc1Δ) are viable, but display several phenotypes, including osmotic, temperature, and nocodazole sensitivity. We have used a two-hybrid screen to identify Plc1p-interacting proteins. One of the interacting proteins found was Sgd1p, a recently identified, essential, nuclear protein. The SGD1 gene was originally cloned by complementation of an osmostress-sensitive mutant. The Plc1p-Sgd1p interaction was confirmed biochemically by affinity chromatography. SGD1 interacts genetically with both PLC1 and HOG1 (which encodes an osmosensing mitogen-activated protein kinase). Overexpression of Sgd1p suppresses the temperature sensitivity of cells bearing the plc1-4 allele, and the double mutant strain plc1Δ sgd1-1 displays enhanced temperature and nocodazole sensitivity. The plc1Δ hog1Δ strain displays increased osmosensitivity, and has a synthetic defect in glycerol synthesis and the expression of GPD1 (which encodes the enzyme glycerol 3-phosphate dehydrogenase that is involved in glycerol biosynthesis), suggesting that Plc1p and Hog1p function in independent pathways. The hog1Δ sgd1-1 double mutant displays enhanced osmosensitivity relative to that of either single mutant. The triple mutant plc1Δ hog1Δ sgd1-1 is inviable, while the plc1Δ hog1Δ sgd1-2 strain grows extremely slowly and is more osmosensitive than the plc1Δ hog1Δ or hog1Δ sgd1-2 strain. These results are consistent with a model in which Plc1p and Hog1p function in parallel pathways affecting osmoregulation, and signals from both these pathways converge, at least partly, on Sgd1p.

Yeast Osmoregulation PLC1 SGD1 HOG1 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  •  H. Lin
    • 1
  •  P. Nguyen
    • 1
  •  A. Vancura
    • 1
  1. 1.Department of Biological Sciences, St. John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA.
  2. 2.Present address: Rockefeller University, New York, NY 10021, USA

Personalised recommendations