{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Santiago-Tirado FH"],"funding":["Deutsche Forschungsgemeinschaft","Universität des Saarlandes","NIAID NIH HHS","Burroughs Wellcome Fund","HHS | NIH | National Institute of Allergy and Infectious Diseases","Canada Foundation for Innovation","Canadian Institutes for Health Research","HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)","CIHR"],"pagination":["e0338422"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC9973365"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["14(1)"],"pubmed_abstract":["The fungal pathogen Cryptococcus neoformans is distinguished by a cell-wall-anchored polysaccharide capsule that is critical for virulence. Biogenesis of both cell wall and capsule relies on the secretory pathway. Protein secretion begins with polypeptide translocation across the endoplasmic reticulum (ER) membrane through a highly conserved channel formed by three proteins: Sec61, Sbh1, and Sss1. Sbh1, the most divergent, contains multiple phosphorylation sites, which may allow it to regulate entry into the secretory pathway in a species- and protein-specific manner. Absence of <i>SBH1</i> causes a cell-wall defect in both Saccharomyces cerevisiae and C. neoformans, although other phenotypes differ. Notably, proteomic analysis showed that when cryptococci are grown in conditions that mimic aspects of the mammalian host environment (tissue culture medium, 37°C, 5% CO<sub>2</sub>), a set of secretory and transmembrane proteins is upregulated in wild-type, but not in <i>Δsbh1</i> mutant cells. The Sbh1-dependent proteins show specific features of their ER targeting sequences that likely cause them to transit less efficiently into the secretory pathway. Many also act in cell-wall biogenesis, while several are known virulence factors. Consistent with these observations, the C. neoformans <i>Δsbh1</i> mutant is avirulent in a mouse infection model. We conclude that, in the context of conditions encountered during infection, Sbh1 controls the entry of virulence factors into the secretory pathway of C. neoformans, and thereby regulates fungal pathogenicity. <b>IMPORTANCE</b> Cryptococcus neoformans is a yeast that causes almost 200,000 deaths worldwide each year, mainly of immunocompromised individuals. The surface structures of this pathogen, a protective cell wall surrounded by a polysaccharide capsule, are made and maintained by proteins that are synthesized inside the cell and travel outwards through the secretory pathway. A protein called Sbh1 is part of the machinery that determines which polypeptides enter this export pathway. We found that when Sbh1 is absent, both C. neoformans and the model yeast S. cerevisiae show cell-wall defects. Lack of Sbh1 also changes the pattern of secretion of both transmembrane and soluble proteins, in a manner that depends on characteristics of their sequences. Notably, multiple proteins that are normally upregulated in conditions similar to those encountered during infection, including several needed for cryptococcal virulence, are no longer increased. Sbh1 thereby regulates the ability of this important pathogen to cause disease."],"journal":["mBio"],"pubmed_title":["The ER Protein Translocation Channel Subunit Sbh1 Controls Virulence of Cryptococcus neoformans."],"pmcid":["PMC9973365"],"funding_grant_id":["AI140979","He3875/15-1","Posdoctoral Enrichment Program Award","AI007172","R21 AI140979","Project Grant","R21 AI171742","JELF #38798","AI135012","R01 AI135012"],"pubmed_authors":["Geddes-McAlister J","Helms V","Santiago-Tirado FH","Hurtaux T","Nguyen D","Doering TL","Romisch K"],"additional_accession":[]},"is_claimable":false,"name":"The ER Protein Translocation Channel Subunit Sbh1 Controls Virulence of Cryptococcus neoformans.","description":"The fungal pathogen Cryptococcus neoformans is distinguished by a cell-wall-anchored polysaccharide capsule that is critical for virulence. Biogenesis of both cell wall and capsule relies on the secretory pathway. Protein secretion begins with polypeptide translocation across the endoplasmic reticulum (ER) membrane through a highly conserved channel formed by three proteins: Sec61, Sbh1, and Sss1. Sbh1, the most divergent, contains multiple phosphorylation sites, which may allow it to regulate entry into the secretory pathway in a species- and protein-specific manner. Absence of <i>SBH1</i> causes a cell-wall defect in both Saccharomyces cerevisiae and C. neoformans, although other phenotypes differ. Notably, proteomic analysis showed that when cryptococci are grown in conditions that mimic aspects of the mammalian host environment (tissue culture medium, 37°C, 5% CO<sub>2</sub>), a set of secretory and transmembrane proteins is upregulated in wild-type, but not in <i>Δsbh1</i> mutant cells. The Sbh1-dependent proteins show specific features of their ER targeting sequences that likely cause them to transit less efficiently into the secretory pathway. Many also act in cell-wall biogenesis, while several are known virulence factors. Consistent with these observations, the C. neoformans <i>Δsbh1</i> mutant is avirulent in a mouse infection model. We conclude that, in the context of conditions encountered during infection, Sbh1 controls the entry of virulence factors into the secretory pathway of C. neoformans, and thereby regulates fungal pathogenicity. <b>IMPORTANCE</b> Cryptococcus neoformans is a yeast that causes almost 200,000 deaths worldwide each year, mainly of immunocompromised individuals. The surface structures of this pathogen, a protective cell wall surrounded by a polysaccharide capsule, are made and maintained by proteins that are synthesized inside the cell and travel outwards through the secretory pathway. A protein called Sbh1 is part of the machinery that determines which polypeptides enter this export pathway. We found that when Sbh1 is absent, both C. neoformans and the model yeast S. cerevisiae show cell-wall defects. Lack of Sbh1 also changes the pattern of secretion of both transmembrane and soluble proteins, in a manner that depends on characteristics of their sequences. Notably, multiple proteins that are normally upregulated in conditions similar to those encountered during infection, including several needed for cryptococcal virulence, are no longer increased. Sbh1 thereby regulates the ability of this important pathogen to cause disease.","dates":{"release":"2023-01-01T00:00:00Z","publication":"2023 Feb","modification":"2026-06-14T06:26:38.561Z","creation":"2025-02-19T04:54:57.287Z"},"accession":"S-EPMC9973365","cross_references":{"pubmed":["36749043"],"doi":["10.1128/mbio.03384-22"]}}