Protein O-mannosylation is crucial for cell wall integrity, septation and viability in fission yeast

Cytokinesis is a complicated yet conserved step of the cell-division cycle that requires the coordination of multiple proteins and cellular processes. Here we describe a previously uncharacterized protein, Ync13, and its roles during fission yeast cytokinesis. Ync13 is a member of the UNC-13/Munc13 protein family, whose animal homologues are essential priming factors for soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex assembly during exocytosis in various cell types, but no roles in cytokinesis have been reported. We find that Ync13 binds to lipids in vitro and dynamically localizes to the plasma membrane at cell tips during interphase and at the division site during cytokinesis. Deletion of Ync13 leads to defective septation and exocytosis, uneven distribution of cell-wall enzymes and components of cell-wall integrity pathway along the division site and massive cell lysis during cell separation. Interestingly, loss of Ync13 compromises endocytic site selection at the division plane. Collectively, we find that Ync13 has a novel function as an UNC-13/Munc13 protein in coordinating exocytosis, endocytosis, and cell-wall integrity during fission yeast cytokinesis.

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zds1, a Novel Gene Encoding an Ortholog of Zds1 and Zds2, Controls Sexual Differentiation, Cell Wall Integrity and Cell Morphology in Fission Yeast

Genetics ◽

10.1534/genetics.105.050906 ◽

2005 ◽

Vol 172 (2) ◽

pp. 811-825 ◽

Cited By ~ 18

Author(s):

Miyo Yakura ◽

Fumiyo Ozoe ◽

Hideki Ishida ◽

Tsuyoshi Nakagawa ◽

Katsunori Tanaka ◽

...

Keyword(s):

Cell Wall ◽

Fission Yeast ◽

Cell Morphology ◽

Sexual Differentiation ◽

Cell Wall Integrity ◽

Gene Encoding ◽

Novel Gene

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NADPH-Cytochrome P450 Reductase Ccr1 Is a Target of Tamoxifen and Participates in Its Antifungal Activity via Regulating Cell Wall Integrity in Fission Yeast

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00079-20 ◽

2020 ◽

Vol 64 (9) ◽

Author(s):

Qiannan Liu ◽

Xiaoxu Guo ◽

Guanglie Jiang ◽

Guoxiang Wu ◽

Hao Miao ◽

...

Keyword(s):

Cell Wall ◽

Cytochrome P450 ◽

Fission Yeast ◽

Antifungal Drugs ◽

Cell Wall Integrity ◽

Cytochrome P450 Reductase ◽

Content Type ◽

Nadph Cytochrome ◽

P450 Reductase ◽

Nadph Cytochrome P450 Reductase

ABSTRACT Invasive fungal diseases are a leading cause of mortality among immunocompromised populations. Treatment is notoriously difficult due to the limited number of antifungal drugs as well as the emergence of drug resistance. Tamoxifen (TAM), a selective estrogen receptor modulator frequently used for the treatment of breast cancer, has been found to have antifungal activities and may be a useful addition to the agents used to treat fungal infectious diseases. However, the molecular mechanisms underlying its antifungal actions remain obscure. Here, we screened for mutations that confer sensitivity to azole antifungal drugs by using the fission yeast Schizosaccharomyces pombe as a model and isolated a mutant with a mutation in cls1 (ccr1), an allele of the gene encoding the NADPH-cytochrome P450 reductase Ccr1. We found that strains with a deletion of the ccr1+ gene exhibited hypersensitivities to various drugs, including antifungal drugs (azoles, terbinafine, micafungin), the immunosuppressor FK506, and the anticancer drugs TAM and 5-fluorouracil (5-FU). Unexpectedly, the overexpression of Ccr1 caused yeast cell resistance to TAM but not the other drugs tested here. Additionally, strains with a deletion of Ccr1 displayed pleiotropic phenotypes, including defects in cell wall integrity and vacuole fusion, enhanced calcineurin activity, as well as increased intracellular Ca2+ levels. Overexpression of the constitutively active calcineurin suppressed the drug-sensitive phenotypes of the Δccr1 cells. Notably, TAM treatment of wild-type cells resulted in pleiotropic phenotypes, similar to those of cells lacking Ccr1. Furthermore, TAM inhibited Ccr1 NADPH-cytochrome P450 reductase activities in a dose-dependent manner. Moreover, TAM treatment also inhibited the NADPH-cytochrome P450 reductase activities of Candida albicans and resulted in defective cell wall integrity. Collectively, our findings suggest that Ccr1 is a novel target of TAM and is involved in the antifungal activity of TAM by regulating cell wall integrity in fission yeast.

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Novel Rho GTPase Involved in Cytokinesis and Cell Wall Integrity in the Fission Yeast Schizosaccharomyces pombe

Eukaryotic Cell ◽

10.1128/ec.2.3.521-533.2003 ◽

2003 ◽

Vol 2 (3) ◽

pp. 521-533 ◽

Cited By ~ 39

Author(s):

Beatriz Santos ◽

Javier Gutiérrez ◽

Teresa M. Calonge ◽

Pilar Pérez

Keyword(s):

Cell Wall ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Rho Gtpases ◽

Rho Gtpase ◽

Cell Wall Integrity ◽

Glucan Synthase ◽

Actin Organization ◽

Morphological Defects

ABSTRACT The Rho family of GTPases is present in all eukaryotic cells from yeast to mammals; they are regulators in signaling pathways that control actin organization and morphogenetic processes. In yeast, Rho GTPases are implicated in cell polarity processes and cell wall biosynthesis. It is known that Rho1 and Rho2 are key proteins in the construction of the cell wall, an essential structure that in Schizosaccharomyces pombe is composed of β-glucan, α-glucan, and mannoproteins. Rho1 regulates the synthesis of 1,3-β-d-glucan by activation of the 1,3-β-d-glucan synthase, and Rho2 regulates the synthesis of α-glucan by the 1,3-α-d-glucan synthase Mok1. Here we describe the characterization of another Rho GTPase in fission yeast, Rho4. rho4Δ cells are viable but display cell separation defects at high temperature. In agreement with this observation, Rho4 localizes to the septum. Overexpression of rho4 + causes lysis and morphological defects. Several lines of evidence indicate that both rho4 + deletion or rho4 + overexpression result in a defective cell wall, suggesting an additional role for Rho4 in cell wall integrity. rho4Δ cells also accumulate secretory vesicles around the septum and are defective in actin polarization. We propose that Rho4 could be involved in the regulation of the septum degradation during cytokinesis.

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