Multiple functions of ergosterol in the fission yeast Schizosaccharomyces pombe.
Sterols are a major class of membrane lipids in eukaryotes. In Schizosaccharomyces pombe, sterol 24-C-methyltransferase (Erg6p), C-8 sterol isomerase (Erg2p), C-5 sterol desaturase (Erg31p, Erg32p), C-22 sterol desaturase (Erg5p) and C-24 (28) sterol reductase (Sts1p/Erg4p) have been predicted, but not yet determined, to catalyse a sequence of reactions from zymosterol to ergosterol. Disruption mutants of these genes were unable to synthesize ergosterol, and most were tolerant to the polyene drugs amphotericin B and nystatin. Disruption of erg31(+) or erg32(+) did not cause ergosterol deficiency or tolerance to polyene drugs, indicating that the two C-5 sterol desaturases have overlapping functions. GFP-tagged DRM (detergent-resistant membrane)-associated protein Pma1p localized to the plasma membrane in ergDelta mutants. DRM fractionation revealed that the association between Pma1-GFP and DRM was weakened in erg6Delta but not in other erg mutants. Several GFP-tagged plasma membrane proteins were tested, and an amino acid permease homologue, SPBC359.03c, was found to mislocalize to intracellular punctate structures in the ergDelta mutants. These results indicate that these proteins are responsible for ergosterol biosynthesis in fission yeast, similar to the situation in Saccharomyces cerevisiae. Furthermore, in fission yeast, ergosterol is important for plasma membrane structure and function and for localization of plasma membrane proteins.
Iwaki
Tomoko
T
Research Center, Asahi Glass Co. Ltd, Yokohama, Kanagawa 221-8755, Japan.|Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan.
Iefuji
Haruyuki
H
National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashi Hiroshima, Hiroshima 739-0046, Japan.
Hiraga
Yoshikazu
Y
Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi Hiroshima, Hiroshima 739-8526, Japan.
Hosomi
Akira
A
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan.
Morita
Tomotake
T
Research Center, Asahi Glass Co. Ltd, Yokohama, Kanagawa 221-8755, Japan.|Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan.
Giga-Hama
Yuko
Y
Research Center, Asahi Glass Co. Ltd, Yokohama, Kanagawa 221-8755, Japan.
Takegawa
Kaoru
K
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan.
D026905:Amino Acid Transport Systems / Q000032:analysis; D000666:Amphotericin B / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology; D002458:Cell Fractionation; D025141:Drug Resistance, Fungal / Q000235:genetics; D004798:Enzymes / Q000235:genetics / Q000378:metabolism*; D004875:Ergosterol / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis; D016254:Mutagenesis, Insertional; D009761:Nystatin / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics
D026905:Amino Acid Transport Systems; D000935:Antifungal Agents; D004798:Enzymes; D005656:Fungal Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D009761:Nystatin; D049452:Green Fluorescent Proteins; D000666:Amphotericin B; D004875:Ergosterol