title: Multiple cysteine residues are necessary for sorting and transport activity of the arsenite permease Acr3p from Saccharomyces cerevisiae.
abstract: The yeast transporter Acr3p is a low affinity As(III)/H(+) and Sb(III)/H(+) antiporter located in the plasma membrane. It has been shown for bacterial Acr3 proteins that just a single cysteine residue, which is located in the middle of the fourth transmembrane region and conserved in all members of the Acr3 family, is essential for As(III) transport activity. Here, we report a systematic mutational analysis of all nine cysteine residues present in the Saccharomyces cerevisiae Acr3p. We found that mutagenesis of highly conserved Cys151 resulted in a complete loss of metalloid transport function. In addition, lack of Cys90 and Cys169, which are conserved in eukaryotic members of Acr3 family, impaired Acr3p trafficking to the plasma membrane and greatly reduced As(III) efflux, respectively. Mutagenesis of five other cysteines in Acr3p resulted in moderate reduction of As(III) transport capacities and sorting perturbations. Our data suggest that interaction of As(III) with multiple thiol groups in the yeast Acr3p may facilitate As(III) translocation across the plasma membrane.
authors.affiliation: Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Maciaszczyk-Dziubinska
authors.affiliation: Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Migocka
authors.affiliation: Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland.
authors.forename: Donata
authors.initials: D
authors.lastname: Wawrzycka
authors.affiliation: Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Markowska
authors.affiliation: Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland. Electronic address: robert.wysocki@biol.uni.wroc.pl.
authors.forename: Robert
authors.initials: R
authors.lastname: Wysocki
mesh_terms: D018053:Arsenites / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: C109281:ACR3 protein, S cerevisiae; D018053:Arsenites; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D003545:Cysteine; C015001:arsenite
keywords: Acr3 permease; Arsenite transporter; As(III); As(V); ER; Mutagenesis; Plasma membrane; Sb(III); TM; Yeast; antimonite; arsenate; arsenite; endoplasmic reticulum; transmembrane segment