The putative flippase Apt1 is required for intracellular membrane architecture and biosynthesis of polysaccharide and lipids in Cryptococcus neoformans

Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Instituto de Microbiologia Paulo de Góes. Rio de Janeiro, RJ, Brasil.
Stony Brook University. Departments of Biochemistry and Molecular Genetics and Microbiology. New York, USA / Universidade Federal do Rio de Janeiro. Programa de Pós-Graduação em Química Biológica do Instituto de Bioquímica Médica. Rio de Janeiro, RJ, Brazil.
Albert Einstein College of Medicine. Departments of Medicine and Microbiology and Immunology. New York, USA.
Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Instituto de Microbiologia Paulo de Góes. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Programa de Pós-Graduação em Biologia Parasitária. Rio de Janeiro, RJ, Brasil.
Virginia Commonwealth University School of Medicine. Department of Biochemistry and Molecular Biology. Richmond, USA.
Johns Hopkins Bloomberg School of Public Health. Department of Molecular Microbiology and Immunology. Baltimore, USA.
Stony Brook University. Departments of Biochemistry and Molecular Genetics and Microbiology. Division of Infectious Diseases. New York, USA / Veterans Administration Medical Center. Northport, USA.
Albert Einstein College of Medicine. Departments of Medicine and Microbiology and Immunology. New York, USA.
The University of British Columbia. Faculty of Land and Food Systems. Department of Microbiology and Immunology. Michael Smith Laboratories. Vancouver, Canada
Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Instituto de Microbiologia Paulo de Góes. Rio de Janeiro, RJ, Brasil.

Abstract

Flippases are responsible for the asymmetric distribution of phospholipids in biological membranes. In the encapsulated fungal pathogen Cryptococcus neoformans, the putative flippase Apt1 is an important regulator of polysaccharide secretion and pathogenesis in mice by unknown mechanisms. In this study, we analyzed the role of C. neoformans Apt1 in intracellular membrane architecture and synthesis of polysaccharide and lipids. Analysis of wild type (WT), apt1Δ (mutant) and apt1Δ::APT1 (complemented) strains by transmission electron microscopy revealed that deletion of APT1 resulted in the formation of irregular vacuoles. Disorganization of vacuolar membranes in apt1Δ cells was accompanied by a significant increase in the amounts of intra-vacuolar and pigment-containing vesicles. Quantitative immunogold labeling of C. neoformans cells with a monoclonal antibody raised to a major capsular component suggested impaired polysaccharide synthesis. APT1 deletion also affected synthesis of phosphatidylserine, phosphatidylethanolamine, inositolphosphoryl ceramide, glucosylceramide and ergosterylglycoside. These results reveal novel functions of Apt1 and are in agreement with the notion that this putative flippase plays an important role in the physiology of C. neoformans.

Keywords

Cryptococcus neoformans
Flippases
Vacuole
Polysaccharide secretion
Lipid biosynthesis

Publisher

Elsevier

Citation

RIZZO, J. et al. The putative fl ippase Apt1 is required for intracellular membrane architecture and biosynthesis of polysaccharide and lipids in Cryptococcus neoformans. BBA - Molecular Cell Research, v. 1865, p. 532-541, 2018.

DOI

10.1016/j.bbamcr.2017.12.007

ISSN

0167-4889

Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/31007

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Restricted access

Embargo date

2022-01-01

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