Genes encoding proteins of the cation diffusion facilitator family that confer manganese tolerance.
The yeast Saccharomyces cerevisiae expressing a cDNA library prepared from Stylosanthes hamata was screened for enhanced Mn(2+) tolerance. From this screen, we identified four related cDNAs that encode membrane-bound proteins of the cation diffusion facilitator (CDF) family. One of these cDNAs (ShMTP1) was investigated in detail and found to confer Mn(2+) tolerance to yeast by internal sequestration rather than by efflux of Mn(2+). Expression of ShMTP1 in a range of yeast mutants suggested that it functions as a proton:Mn(2+) antiporter on the membrane of an internal organelle. Similarly, when expressed in Arabidopsis, ShMTP1 conferred Mn(2+) tolerance through internal sequestration. The ShMTP1 protein fused to green fluorescent protein was localized to the tonoplast of Arabidopsis cells but appeared to localize to the endoplasmic reticulum of yeast. We suggest that the ShMTP1 proteins are members of the CDF family involved in conferring Mn(2+) tolerance and that at least one of these proteins (ShMTP1) confers tolerance by sequestering Mn(2+) into internal organelles.
Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra ACT 2601, Australia. manny.delhaize@csiro.au
Emmanuel
E
Delhaize
Tatsuhiko
T
Kataoka
Diane M
DM
Hebb
Rosemary G
RG
White
Peter R
PR
Ryan
D000222:Adaptation, Physiological / Q000235:genetics; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism; D007887:Fabaceae / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008345:Manganese / Q000378:metabolism* / Q000494:pharmacology; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D027682:Cation Transport Proteins; D018076:DNA, Complementary; D008164:Luminescent Proteins; D010940:Plant Proteins; D020033:Protein Isoforms; D049452:Green Fluorescent Proteins; D008345:Manganese