Identification of a Candida glabrata homologue of the S. cerevisiae VRG4 gene, encoding the Golgi GDP-mannose transporter.
Mannoproteins on the cell wall of yeast and fungi help regulate cell shape, porosity, and cell-cell interactions, including those required for attachment to host cells by fungal pathogens. The mannose-containing oligosaccharides on proteins and lipids are extended in the Golgi by glycosyltransferases that use GDP-mannose as the sugar substrate. A membrane-bound transporter that, in Saccharomyces cerevisiae, is encoded by the VRG4 gene catalyses delivery of GDP-mannose into the lumen of the Golgi. We report here the cloning of the homologous VRG4 gene from the pathogenic yeast, Candida glabrata, by functional complementation of an S. cerevisiae vrg4 mutant. The sequence of the CgVrg4 protein displays significant homology to GDP-mannose transporters from other yeast, fungi, protozoa, and plants. CgVRG4 fully complements the glycosylation defect and other cell wall associated vrg4 mutant phenotypes. Like ScVRG4, CgVRG4 is essential for the viability of C. glabrata. These results suggest that, as in S. cerevisiae, CgVrg4p accounts for all of the GDP-mannose transport activity in the Golgi lumen.
Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, State University of New York, Stony Brook, NY 11794-5215, USA.
Akiko
A
Nishikawa
Barbara
B
Mendez
Yoshifumi
Y
Jigami
Neta
N
Dean
D000595:Amino Acid Sequence; D001483:Base Sequence; D041221:Candida glabrata / Q000235:genetics* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D015723:Gene Library; D005816:Genetic Complementation Test; D006056:Golgi Apparatus / Q000201:enzymology; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; D004271:DNA, Fungal; C428326:GDP-mannose transporter; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C099493:VRG4 protein, S cerevisiae