The fission yeast <i>gmn2</i>⁺ gene encodes an <i>ERD1</i> homologue of <i>Saccharomyces cerevisiae</i> required for protein glycosylation and retention of luminal endoplasmic reticulum proteins

Abstract

The gmn2 mutant of Schizosaccharomyces pombe has previously been shown to exhibit defects in protein glycosylation of N-linked oligosaccharides (Ballou, L. and Ballou, CE., Proc. Natl. Acad. Sci. USA, 92, 2790-2794 (1995)). Like most glycosylation-defective mutants, the S. pombe gmn2 mutant was found to be sensitive to hygromycin B, an aminoglycoside antibiotic. As a result of complementation analysis, the gmn2 + gene was found to be a single open reading frame that encodes a polypeptide of 373 amino acids consisting of multiple membrane-spanning regions. The Gmn2 protein shares sequence similarity with Kluyveromyces lactis and Saccharomyces cerevisiae Erd1 proteins, which are required for retention of luminal endoplasmic reticulum (ER) proteins. Although disruption of the gmn2 + gene is not lethal, the secreted glycoprotein showed a significant glycosylation defect with destabilization of the glycosyltransferase responsible for N-glycan elongation. It was also shown that a significant amount of BiP was missorted to the cell surface according to ADEL receptor destabilization. Fluorescent microscopy revealed that the functional Gmn2-EGFP fusion protein is mainly localized in the Golgi membrane.These results indicate that the Gmn2 protein is required for protein glycosylation and for retention of ER-resident proteins in S. pombe cells.

Humanization of Yeasts for Glycan-Type End-Products

“…Arxula adeninivorans is an unconventional, non-pathogenic, and haploid yeast and maybe a new expression platform (Song et al, 2007 ). Brettanomyces bruxellensis , a wine yeast, mainly contributes to spontaneous beer fermentations associated with industrial fermentation ecosystems (Tanaka et al, 2021 ). Brettanomyces claussenii , a yeast often found on pineapple or other tropical fruits, expands the potential for the valorization of dairy by-products to functional beverages (Turakainen et al, 1994 ).…”