Previous Article | Next Article ![]()
Mol. Cell. Biol., 10 1995, 5470-5481, Vol 15, No. 10
A Ferrando, SJ Kron, G Rios, GR Fink and R Serrano
Dynamic regulation of ion transport is essential for homeostasis as cells
confront changes in their environment. The gene HAL3 encodes a novel
component of this regulatory circuit in the yeast Saccharomyces cerevisiae.
Overexpression of HAL3 improves growth of wild-type cells exposed to toxic
concentrations of sodium and lithium and suppresses the salt sensitivity
conferred by mutation of the calcium-dependent protein phosphatase
calcineurin. Null mutants of HAL3 display salt sensitivity. The sequence of
HAL3 gives little clue to its function. However, alterations in
intracellular cation concentrations associated with changes in HAL3
expression suggest that HAL3 activity may directly increase cytoplasmic K+
and decrease Na+ and Li+. Cation efflux in S. cerevisiae is mediated by the
P-type ATPase encoded by the ENA1/PMR24 gene, a putative plasma membrane
Na+ pump whose expression is salt induced. Acting in concert with
calcineurin, HAL3 is necessary for full activation of ENA1 expression. This
functional complementarity is also reflected in the participation of both
proteins in recovery from alpha- factor-induced growth arrest. Recently,
HAL3 was isolated as a gene (named SIS2) which when overexpressed partially
relieves loss of transcription of G1 cyclins in mutants lacking the protein
phosphatase Sit4p. Therefore, HAL3 influences cell cycle control and ion
homeostasis, acting in parallel to the protein phosphatases Sit4p and
calcineurin.
Copyright © 1995, American Society for Microbiology
Regulation of cation transport in Saccharomyces cerevisiae by the salt tolerance gene HAL3
Instituto de Biologia Molecular y Celular de Plantas, Universidad Politecnica de Valencia-Consejo Superior de Investigaciones Cientificas, Spain.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|