Metalloid tolerance based on phytochelatins is not functionally equivalent to the arsenite transporter Acr3p.

• Active transport of metalloids by Acr3p and Ycf1p in Saccharomyces cerevisiae and chelation by phytochelatins in Schizosaccharomyces pombe, nematodes, and plants represent distinct strategies of metalloid detoxification. In this report, we present results of functional comparison of both resistance mechanisms. The S. pombe and wheat phytochelatin synthase (PCS) genes, when expressed in S. cerevisiae, mediate only modest resistance to arsenite and thus cannot functionally compensate for Acr3p. On the other hand, we show for the first time that phytochelatins also contribute to antimony tolerance as PCS fully complement antimonite sensitivity of ycf1Delta mutant. Remarkably, heterologous expression of PCS sensitizes S. cerevisiae to arsenate, while ACR3 confers much higher arsenic resistance in pcsDelta than in wild-type S. pombe. The analysis of PCS and ACR3 homologues distribution in various organisms and our experimental data suggest that separation of ACR3 and PCS genes may lead to the optimal tolerance status of the cell.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

Aminoacyltransferases

classification

genetics

physiology

Antimony

pharmacology

Arsenic

pharmacology

Arsenites

metabolism

Biological Transport

Active

Drug Resistance

Fungal

Glutathione

Membrane Proteins

classification

physiology

Membrane Transport Proteins

classification

physiology

Metalloproteins

physiology

Metals

pharmacology

Mutation

Phylogeny

Phytochelatins

Saccharomyces cerevisiae

drug effects

enzymology

metabolism

Saccharomyces cerevisiae Proteins

Schizosaccharomyces

drug effects

enzymology

metabolism

Yeasts

drug effects

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)