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SSU1 mediates sulphite efflux in Saccharomyces cerevisiae
Author(s) -
Park Hoon,
Bakalinsky Alan T.
Publication year - 2000
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/1097-0061(200007)16:10<881::aid-yea576>3.0.co;2-3
Subject(s) - efflux , biology , saccharomyces cerevisiae , mutant , biochemistry , wild type , microbiology and biotechnology , gene
Ssu1p, a plasma membrane protein involved in sulphite metabolism in Saccharomyces cerevisiae , was found to be required for efficient sulphite efflux. An SSU1 null mutant accumulated significantly more sulphite than wild‐type, whereas cells expressing multicopy SSU1 accumulated significantly less. Cells expressing FZF1‐4 , a dominant allele of a transcriptional activator of SSU1 that confers sulphite resistance, also accumulated less sulphite. β‐galactosidase activity in the FZF1‐4 strain carrying an SSU1::lacZ fusion was found to be 8.5‐fold higher than in a strain carrying wild‐type FZF1 , confirming that the heightened resistance was correlated with hyperactivation of SSU1 . Multicopy SSU1 was also found to increase the sulphite resistance of a number of unrelated sulphite‐sensitive strains by a factor of 3‐ to 8‐fold. Rates of efflux of free sulphite from cells expressing multicopy SSU1 or FZF1‐4 were significantly greater than that from wild‐type or from a SSU1 null mutant. Rates of efflux of bound sulphite from wild‐type, a SSU1 null mutant, a FZF1‐4 mutant, or cells expressing multicopy SSU1 were not significantly different, suggesting that Ssu1p specifically mediates efflux of the free form of sulphite. Copyright © 2000 John Wiley & Sons, Ltd.