A GENETIC-ANALYSIS OF THE ROLE OF CALCINEURIN AND CALMODULIN IN CA-DEPENDENT IMPROVEMENT OF NACL TOLERANCE OF SACCHAROMYCES-CEREVISIAE(+)

Citation
A. Danielsson et al., A GENETIC-ANALYSIS OF THE ROLE OF CALCINEURIN AND CALMODULIN IN CA-DEPENDENT IMPROVEMENT OF NACL TOLERANCE OF SACCHAROMYCES-CEREVISIAE(+), Current genetics, 30(6), 1996, pp. 476-484
Citations number
40
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Genetics & Heredity
Journal title
ISSN journal
0172-8083
Volume
30
Issue
6
Year of publication
1996
Pages
476 - 484
Database
ISI
SICI code
0172-8083(1996)30:6<476:AGOTRO>2.0.ZU;2-#
Abstract
Mutants of Saccharomyces cerevisiae lacking activity of the Ca2+/calmo dulin-dependent protein phosphatase calcineurin, show sensitivity to h igh concentrations of sodium that is partly reversed by the external s upply of Ca2+ On long-time exposure to NaCl stress the mutants display an increased intracellular Na+/K+ ratio which is partially corrected by the addition of Ca2+, improving the sodium efflux of not only calci neurin-defective cells but also wild-type cells. We also demonstrate t hat the NaCl sensitivity of cmd mutants, expressing modified forms of calmodulin that do not bind Ca2+, is strongly reversed by the addition of Ca2+ This effect is highly dependent on calcineurin, since the NaC l tolerance of a cmdl-3 strain, carrying an additional mutation in cal cineurin, is only slightly assisted by Ca2+ A striking characteristic of the loss of function of calcineurin is a several-fold increased con tent of intracellular Ca2+, localized mainly in subcellular compartmen t(s). If the compartmentalized Ca2+ pool is brought back to normal lev els by an additional inactivating mutation of the vacuolar Ca2+ transp orting ATPase, such double mutants do not significantly improve their tolerance to NaCl.