Open AccessRole of the yeast multidrug transporter Q dr2 in cation homeostasis and the oxidative stress response
Author(s) -
Ríos Gabino,
Cabedo Marc,
Rull Baltasar,
Yenush Lynne,
Serrano Ramón,
Mulet José M.
Publication year - 2013
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/1567-1364.12013
Subject(s) - major facilitator superfamily , oxidative stress , biology , biochemistry , transporter , divalent , reactive oxygen species , efflux , hydrogen peroxide , microbiology and biotechnology , chemistry , gene , organic chemistry
We have identified QDR2 in a screening for genes able to confer tolerance to sodium and/or lithium stress upon overexpression. Q dr2 is a multidrug transporter of the major facilitator superfamily, originally described for its ability to transport the antimalarial drug quinidine and the herbicide barban. To identify its physiological substrate, we have screened for phenotypes dependent on QDR2 and found that Q dr2 is able to transport monovalent and divalent cations with poor selectivity, as shown by growth tests and the determination of internal cation content. Moreover, strains overexpressing or lacking QDR2 also exhibit phenotypes when reactive oxygen species‐ producing agents, such as hydrogen peroxide or menadione were added to the growth medium. We have also found that the presence of copper and hydrogen peroxide repress the expression of QDR2 . In addition, the copper uptake of a qdr2 mutant strain is similar to a wild type, but the extrusion is clearly impaired. Based on our results, we propose that free divalent copper is the main physiological substrate of Q dr2. As copper is a substrate for several redox reactions that occur within the cytoplasm, its function in copper homeostasis explains its role in the oxidative stress response.