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This Article Full Text Full Text (PDF) All Versions of this Article: mic.0.025981-0v1 155/6/2021    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Pacheco, A. Articles by Sousa, M. J. Search for Related Content PubMed PubMed Citation Articles by Pacheco, A. Articles by Sousa, M. J. Agricola Articles by Pacheco, A. Articles by Sousa, M. J.

Small heat-shock protein Hsp12 contributes to yeast tolerance to freezing stress

CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal

The HSP12 gene encodes one of the two major small heat-shock proteins of Saccharomyces cerevisiae and is induced under different conditions, such as low and high temperatures, osmotic or oxidative stress and high sugar or ethanol concentrations. However, few studies could demonstrate any correlation between HSP12 deletion or overexpression and a phenotype of sensitivity/resistance, making it difficult to attribute a role for Hsp12p under several of these stress conditions. We investigated the possible role of Hsp12p in yeast freezing tolerance. Contrary to what would be expected, the hsp12 null mutant when subjected to prolonged storage at –20 °C showed an increased resistance to freezing when compared with the isogenic wild-type strain. Because the mutant strain displayed a higher intracellular trehalose concentration than the wild-type, which could mask the effect of manipulating HSP12, we overexpressed the HSP12 gene in a trehalose-6-phosphate synthase (TPS1) null mutant. The tps1 strain overexpressing HSP12 showed an increase in resistance to freezing storage, indicating that Hsp12p plays a role in freezing tolerance in a way that seems to be interchangeable with trehalose. In addition, we show that overexpression of HSP12 in this tps1 strain also increased resistance to heat shock and that absence of HSP12 compromises the ability of yeast cells to accumulate high levels of trehalose in response to a mild heat stress.

Correspondence
M. J. Sousa
mjsousa{at}bio.uminho.pt