TY - JOUR
T1 - Sec6-dependent sorting of fungal extracellular exosomes and laccase of Cryptococcus neoformans
AU - Panepinto, John
AU - Komperda, Kazimierz
AU - Frases, Susana
AU - Park, Yoon Dong
AU - Djordjevic, Julianne T.
AU - Casadevall, Arturo
AU - Williamson, Peter R.
PY - 2009/3
Y1 - 2009/3
N2 - The cell wall of pathogenic fungi such as Cryptococcus neoformans, provides a formidable barrier to secrete virulence factors that produce host cell damage. To study secretion of virulence factors to the cell periphery, sec6 RNAi mutant strains of C. neoformans were tested for virulence factor expression. The studies reported here show that SEC6 RNAi mutant strains were defective in a number of virulence factors including laccase, urease as well as soluble polysaccharide and demonstrated attenuated virulence in mice. Further analysis by transmission electron microscopy detected the production of abundant extracellular exosomes in wild-type strains containing empty plasmid, but a complete absence in the iSEC6 strain. In addition, a green fluorescent protein-laccase fusion protein demonstrated aberrant localization within cytoplasmic vesicles in iSEC6 strains. In contrast, iSEC6 strains retained normal growth at 37°C, as well as substantially normal capsule formation, phospholipase activity and total secreted protein. These results provide the first molecular evidence for the existence of fungal exosomes and associate these vesicles with the virulence of C. neoformans.
AB - The cell wall of pathogenic fungi such as Cryptococcus neoformans, provides a formidable barrier to secrete virulence factors that produce host cell damage. To study secretion of virulence factors to the cell periphery, sec6 RNAi mutant strains of C. neoformans were tested for virulence factor expression. The studies reported here show that SEC6 RNAi mutant strains were defective in a number of virulence factors including laccase, urease as well as soluble polysaccharide and demonstrated attenuated virulence in mice. Further analysis by transmission electron microscopy detected the production of abundant extracellular exosomes in wild-type strains containing empty plasmid, but a complete absence in the iSEC6 strain. In addition, a green fluorescent protein-laccase fusion protein demonstrated aberrant localization within cytoplasmic vesicles in iSEC6 strains. In contrast, iSEC6 strains retained normal growth at 37°C, as well as substantially normal capsule formation, phospholipase activity and total secreted protein. These results provide the first molecular evidence for the existence of fungal exosomes and associate these vesicles with the virulence of C. neoformans.
UR - http://www.scopus.com/inward/record.url?scp=60649113108&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=60649113108&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2958.2008.06588.x
DO - 10.1111/j.1365-2958.2008.06588.x
M3 - Article
C2 - 19210702
AN - SCOPUS:60649113108
SN - 0950-382X
VL - 71
SP - 1165
EP - 1176
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 5
ER -