PER1, GUP1 and CWH43 of methylotrophic yeast Ogataea minuta are involved in cell wall integrity

Abstract

In eukaryotes, the glycosylphosphatidylinositol (GPI) modification of many glycoproteins on the cell surface is highly conserved. The lipid moieties of GPI-anchored proteins undergo remodelling processes during their maturation. To date, the products of the PER1, GUP1 and CWH43 genes of the yeast Saccharomyces cerevisiae have been shown to be involved in the lipid remodelling. Here, we focus on the putative GPI remodelling pathway in the methylotrophic yeast Ogataea minuta. We found that the O. minuta homologues of PER1, GUP1 and CWH43 are functionally compatible with those of S. cerevisiae. Disruption of GUP1 or CWH43 in O. minuta caused a growth defect under non-permissive conditions. The O. minuta per1Δ mutant exhibited a more fragile phenotype than the gup1Δ or cwh43Δ mutants. To address the role of GPI modification in O. minuta, we assessed the effect of these mutations on the processing and localization of the O. minuta homologues of the Gas1 protein; in S. cerevisiae, Gas1p is an abundant and well-characterized GPI-anchored protein. We found that O. minuta possesses two copies of the GAS1 gene, which we designate GAS1A and GAS1B. Microscopy and western blotting analysis showed mislocalization and/or lower retention of Gas1Ap and Gas1Bp within the membrane fraction in per1Δ or gup1Δ mutant cells, suggesting the significance of lipid remodelling for GPI-anchored proteins in O. minuta. Localization behaviour of Gas1Bp differed from that of Gas1Ap. Our data reveals, for the first time (to our knowledge), the existence of genes related to GPI anchor remodelling in O. minuta cells.

Calcofluor white hypersensitive proteins contribute to stress tolerance and pathogenicity in entomopathogenic fungus, Metarhizium acridum

“…In Δ Macwh mutants, conidial cell wall was impaired due to ~25% reduced chitin, leading to a thinner outermost layer. Also, a 30% decrease in mannose glycoprotein content might result from impeded transfer of GPI‐anchored proteins from the plasma membrane to the cell wall as reported previously in yeast 46–48 . This damage affects cell wall structure, composition and stability, and hence causes increased CFW sensitivity in our mutants, as previously observed in budding yeast 23 …”

“…Also, a 30% decrease in mannose glycoprotein content might result from impeded transfer of GPI-anchored proteins from the plasma membrane to the cell wall as reported previously in yeast. [46][47][48] This damage affects cell wall structure, composition and stability, and hence causes increased CFW sensitivity in our mutants, as previously observed in budding yeast. 23 In addition to involvement in CFW and UV stress tolerance, Macwh1 and Macwh43 also contribute to virulence in M. acridum, a phenomenon not reported in other fungi.…”

“…CWH43 has been reported to function in glucose and nitrogen utilization and lipid metabolism in budding yeast, 46,47 fission yeast 40 and methylotrophic yeast. 48 In ΔMacwh mutants, conidial cell wall was impaired due to ∼25% reduced chitin, leading to a thinner outermost layer. Also, a 30% decrease in mannose glycoprotein content might result from impeded transfer of GPI-anchored proteins from the plasma membrane to the cell wall as reported previously in yeast.…”

“…Therefore, in M. acridum , we speculate that Macwh1 mainly orchestrates cell tolerance to CFW, while Macwh43 is more involved in physiological processes affecting the CFW tolerance. CWH43 has been reported to function in glucose and nitrogen utilization and lipid metabolism in budding yeast, 46,47 fission yeast 40 and methylotrophic yeast 48 . In Δ Macwh mutants, conidial cell wall was impaired due to ~25% reduced chitin, leading to a thinner outermost layer.…”

Quantitative Proteome Profiling Reveals Cellobiose-Dependent Protein Processing and Export Pathways for the Lignocellulolytic Response in Neurospora crassa

“…S2). As observed in yeast (57,61), GPI-anchored proteins in N. crassa are also required for cell wall integrity and, furthermore, cell growth and morphology (62). Therefore, we cannot rule out the possibility that the observed effects of CWH43 on cellulase production is related to cell wall integrity, which has been shown to affect cellulase secretion in N. crassa in previous studies (63,64).…”