title: Sec20p-interacting proteins (Tip20p, Ufe1p) in the retrograde secretory pathway of the fungal pathogen Candida albicans.
abstract: Sec20p is an essential Type-II membrane protein of the human fungal pathogen Candida albicans, which is thought to be involved in mediating retrograde vesicle traffic from the Golgi to the endoplasmic reticulum (ER). Using an epitope-tagged Sec20p we obtained evidence for its localization in ER membranes, which is consistent with its proposed role in an ER-tSNARE complex. Two genes encoding potential interaction partners for Sec20p, Tip20p and Ufe1p, were identified in genomic sequences of C. albicans; these show 18% and 27% identity, respectively, to homologues in Saccharomyces cerevisiae. An interaction between the cytoplasmic domain of Sec20p and Tip20p was demonstrated by two-hybrid analysis; in addition, Tip20p was found to form homodimers. Interaction between Sec20p and Tip20p in vivo was verified by co-immunoprecipation experiments. CaUFE1, which encodes a potential ER-tSNARE, was able to complement a thermosensitive ufe1 mutation in S. cerevisiae, suggesting functional conservation between the two fungal proteins. Thus, although the sequences of some components of the ER-tSNARE complex have diverged considerably during evolution, it appears that they have retained similar functions in C. albicans and S. cerevisiae.
authors.affiliation: Institut für Mikrobiologie, Heinrich-Heine-Universität, Universitätsstrasse 1, Geb. 26.12, 40225 Düsseldorf, Germany.
authors.forename: Y
authors.initials: Y
authors.lastname: Weber
authors.forename: R K
authors.initials: RK
authors.lastname: Swoboda
authors.forename: J F
authors.initials: JF
authors.lastname: Ernst
mesh_terms: D000595:Amino Acid Sequence; D002176:Candida albicans / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane; D017931:DNA Primers / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D021381:Protein Transport; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D005656:Fungal Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; C073173:SEC20 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C070948:TIP1 protein, S cerevisiae; C103868:UFE1 protein, S cerevisiae