The cell wall integrity pathway kinase Mpk1 regulates extracellular vesicle production and apoptotic-like vesicle release in Cryptococcus neoformans
- 1RNA and Extracellular Vesicles Unit, Department of Mycology, Institut Pasteur, Université Paris Cité, Inserm U1359
- 2Platform Cytometry and Biomarkers, Centre de Ressources et Recherches Technologiques (C2RT), Institut Pasteur, Université Paris Cité
- 3Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, Centre de Ressources et Recherches Technologiques (C2RT), Institut Pasteur, Université Paris Cité, CNRS UMR 2000
Abstract
Extracellular vesicles (EVs) are important mediators of fungal physiology and host interactions, yet the mechanisms governing their production remain poorly understood. In Cryptococcus neoformans , EV production is tightly regulated by environmental conditions, suggesting the existence of dedicated signaling pathways. Here, we screened a kinase deletion library to identify regulators of EV production and found that the cell wall integrity (CWI) pathway acts as a major negative regulator of EV production. Deletion of the CWI kinases MPK1 , MKK2 , or BCK1 increased EV release. Unexpectedly, the size of EVs produced by CWI mutants differed markedly from wild type. Accordingly, cryo-electron microscopy revealed the accumulation of larger vesicles with altered size distributions in the mpk1 Δ mutant. These EVs lacked the characteristic mannoprotein-based fibrillar surface decoration observed on most wild-type vesicles, exhibited reduced association with capsular polysaccharide, and contained substantially less protein. Quantitative proteomic analysis demonstrated extensive remodeling of the EV proteome, with depletion of glycosylphosphatidylinositol (GPI)-anchored proteins, and enrichment of ribosomal proteins and histones. Finally, mpk1 Δ EVs displayed several hallmarks of mammalian apoptotic EVs, including phosphatidylserine exposure, and were produced under conditions associated with reduced cell viability. Together, these findings identify the CWI pathway as a central regulator of fungal EV production and provide evidence that C. neoformans produces distinct EV populations through genetically regulated pathways. Our results provide evidence for an apoptotic-like EV population in fungi and reveal an unexpected link between cell wall integrity signaling, cell death, and EV diversity.
IMPORTANCE: Fungal extracellular vesicles (EVs) contribute to virulence, antifungal resistance, and host-pathogen interactions, yet the mechanisms governing their production remain poorly understood. Here, we identify the cell wall integrity signaling pathway as a major regulator of EV production in the human fungal pathogen Cryptococcus neoformans . We further show that disruption of one of the major kinases of this pathway induces the production of a distinct population of EVs with structural and molecular features resembling mammalian apoptotic EVs. These findings demonstrate that fungi produce multiple EV populations through genetically regulated pathways rather than a single constitutive mechanism. By establishing the existence of apoptotic-like EVs in fungi, our work provides new insight into fungal EV production and lays the foundation for investigating how different EV populations contribute to fungal physiology, pathogenesis, and antifungal resistance.
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BibTeX
@article{deculty2026cell,
title = {{The cell wall integrity pathway kinase Mpk1 regulates extracellular vesicle production and apoptotic-like vesicle release in Cryptococcus neoformans}},
author = {Cassandre Deculty and Patricia Flamant and Frédérique Moyrand and Pierre-Henri Commere and Sophie Novault and Magdalena Gil and Rayen Elj and Mariette Matondo and Guilhem Janbon and Isabelle Mouyna},
journal = {mBio},
year = {2026},
month = oct,
doi = {10.1128/mbio.02302-26},
url = {https://journals.asm.org/doi/10.1128/mbio.02302-26},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The cell wall integrity pathway kinase Mpk1 regulates extracellular vesicle production and apoptotic-like vesicle release in Cryptococcus neoformans
AU - Cassandre Deculty
AU - Patricia Flamant
AU - Frédérique Moyrand
AU - Pierre-Henri Commere
AU - Sophie Novault
AU - Magdalena Gil
AU - Rayen Elj
AU - Mariette Matondo
AU - Guilhem Janbon
AU - Isabelle Mouyna
PY - 2026
DA - 2026/10/23
JO - mBio
DO - 10.1128/mbio.02302-26
UR - https://journals.asm.org/doi/10.1128/mbio.02302-26
AB - Extracellular vesicles (EVs) are important mediators of fungal physiology and host interactions, yet the mechanisms governing their production remain poorly understood. In Cryptococcus neoformans , EV production is tightly regulated by environmental conditions, suggesting the existence of dedicated signaling pathways. Here, we screened a kinase deletion library to identify regulators of EV production and found that the cell wall integrity (CWI) pathway acts as a major negative regulator of EV production. Deletion of the CWI kinases MPK1 , MKK2 , or BCK1 increased EV release. Unexpectedly, the size of EVs produced by CWI mutants differed markedly from wild type. Accordingly, cryo-electron microscopy revealed the accumulation of larger vesicles with altered size distributions in the mpk1 Δ mutant. These EVs lacked the characteristic mannoprotein-based fibrillar surface decoration observed on most wild-type vesicles, exhibited reduced association with capsular polysaccharide, and contained substantially less protein. Quantitative proteomic analysis demonstrated extensive remodeling of the EV proteome, with depletion of glycosylphosphatidylinositol (GPI)-anchored proteins, and enrichment of ribosomal proteins and histones. Finally, mpk1 Δ EVs displayed several hallmarks of mammalian apoptotic EVs, including phosphatidylserine exposure, and were produced under conditions associated with reduced cell viability. Together, these findings identify the CWI pathway as a central regulator of fungal EV production and provide evidence that C. neoformans produces distinct EV populations through genetically regulated pathways. Our results provide evidence for an apoptotic-like EV population in fungi and reveal an unexpected link between cell wall integrity signaling, cell death, and EV diversity. IMPORTANCE: Fungal extracellular vesicles (EVs) contribute to virulence, antifungal resistance, and host-pathogen interactions, yet the mechanisms governing their production remain poorly understood. Here, we identify the cell wall integrity signaling pathway as a major regulator of EV production in the human fungal pathogen Cryptococcus neoformans . We further show that disruption of one of the major kinases of this pathway induces the production of a distinct population of EVs with structural and molecular features resembling mammalian apoptotic EVs. These findings demonstrate that fungi produce multiple EV populations through genetically regulated pathways rather than a single constitutive mechanism. By establishing the existence of apoptotic-like EVs in fungi, our work provides new insight into fungal EV production and lays the foundation for investigating how different EV populations contribute to fungal physiology, pathogenesis, and antifungal resistance.
SN - 2150-7511
ER -