Characterization of Lipids and Proteins Associated to the Cell Wall of the Acapsular Mutant Cryptococcus neoformans Cap 67.
Cryptococcus neoformans is an opportunistic human pathogen that causes life-threatening meningitis. In this fungus, the cell wall is exceptionally not the outermost structure due to the presence of a surrounding polysaccharide capsule, which has been highly studied. Considering that there is little information about C. neoformans cell wall composition, we aimed at describing proteins and lipids extractable from this organelle, using as model the acapsular mutant C. neoformans cap 67. Purified cell wall preparations were extracted with either chloroform/methanol or hot sodium dodecyl sulfate. Total lipids fractionated in silica gel 60 were analyzed by electrospray ionization tandem mass spectrometry (ESI-MS/MS), while trypsin digested proteins were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). We detected 25 phospholipid species among phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidic acid. Two glycolipid species were identified as monohexosyl ceramides. We identified 192 noncovalently linked proteins belonging to different metabolic processes. Most proteins were classified as secretory, mainly via nonclassical mechanisms, suggesting a role for extracellular vesicles (EV) in transwall transportation. In concert with that, orthologs from 86% of these proteins have previously been reported both in fungal cell wall and/or in EV. The possible role of the presently described structures in fungal-host relationship is discussed.
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, EPM-UNIFESP, São Paulo, 04023-062, São Paulo, Brazil.
Larissa V G
LV
Longo
Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso (UTEP), El Paso, 79968-0519, Texas, USA.
Ernesto S
ES
Nakayasu
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, EPM-UNIFESP, São Paulo, 04023-062, São Paulo, Brazil.
Jhon H S
JH
Pires
Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso (UTEP), El Paso, 79968-0519, Texas, USA.
Felipe
F
Gazos-Lopes
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, EPM-UNIFESP, São Paulo, 04023-062, São Paulo, Brazil.
Milene C
MC
Vallejo
Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, 13083-970, São Paulo, Brazil.
Tiago J P
TJ
Sobreira
Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso (UTEP), El Paso, 79968-0519, Texas, USA.
Igor C
IC
Almeida
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, EPM-UNIFESP, São Paulo, 04023-062, São Paulo, Brazil.
Rosana
R
Puccia
D002473:Cell Wall / Q000737:chemistry*; D003455:Cryptococcus neoformans / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D009154:Mutation; D011506:Proteins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
D008055:Lipids; D011506:Proteins
Glycolipid; monohexosyl ceramide; pathogenic fungus; phospholipid; proteome