Restriction of copper export in Saccharomyces cerevisiae to a late Golgi or post-Golgi compartment in the secretory pathway.
The CCC2 gene in the yeast Saccharomyces cerevisiae encodes a P-type ATPase (Ccc2p) required for the export of cytosolic copper to the extracytosolic domain of a copper-dependent oxidase, Fet3p. Ccc2p appears to be both a structural and functional homolog of ATPases impaired in two human disorders of intracellular copper transport, Menkes disease and Wilson disease. In the present work, three approaches were used to determine the locus of Ccc2p-dependent copper export within the secretory pathway. First, like ccc2 mutants, sec mutants blocked in the secretory pathway at steps prior to and including the Golgi complex failed to deliver radioactive copper to Fet3p. Second, also like ccc2 mutants, vps33 and certain other mutants with defects in post-Golgi sorting exhibited phenotypes traceable to deficient copper delivery to Fet3p. These findings were sufficient to explain the respiratory deficiency of these mutants. Third, immunofluorescence microscopy revealed that Ccc2p was distributed among several punctate foci within wild-type cells, consistent with late Golgi or post-Golgi localization. Thus, copper export by Ccc2p appears to be restricted to a late or post-Golgi compartment in the secretory pathway.
Yuan
D S
DS
Cell Biology and Metabolism Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
Dancis
A
A
Klausner
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RD
D000251:Adenosine Triphosphatases / Q000378:metabolism; D027682:Cation Transport Proteins; D002451:Cell Compartmentation; D002570:Ceruloplasmin; D003300:Copper / Q000378:metabolism*; D000079922:Copper Transport Proteins; D000079923:Copper Transporter 1; D003600:Cytosol / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D008345:Manganese / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010088:Oxidoreductases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014617:Vacuoles / Q000378:metabolism
C092974:CCC2 protein, S cerevisiae; C490078:CTR1 protein, S cerevisiae; D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; D000079923:Copper Transporter 1; D005656:Fungal Proteins; D008565:Membrane Proteins; C490079:SLC31A1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D008345:Manganese; D003300:Copper; D010088:Oxidoreductases; D002570:Ceruloplasmin; C085513:FET3 protein, S cerevisiae; D000251:Adenosine Triphosphatases