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The human pathogen Cryptococcus neoformans causes meningo-encephalitis. The polysaccharide capsule is an important virulence factor for this yeast-like fungus. Previously, we had shown that disruption of the CAP10 gene, encoding a putative xylosyltransferase, results in mutant cells that lack most of the capsular polysaccharides on the cell surface, but do not show a typical acapsular phenotype. In contrast to the acapsular cap59 mutant, cap10 did not induce maturation of dendritic cells when exposed to components of the immune system. In order to gain further insight into the causes of this phenotype displayed by the cap10 mutant, we performed a more in-depth phenotypic analysis of the cell wall and surface structures of this mutant compared to the wild type strain and acapsular mutant cap59. Moreover, we analyzed the cap10 mutant and the wild type strain for differential gene expression of, amongst others, enzymes that are involved in biogenesis of cell wall and capsule components. We conclude that a mutation in the CAP10 gene results in a pleiotropic phenotype with effects on different cellular processes affecting, amongst others, cell size, expression of virulence factors and size of extracellular vesicles., (Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)

Autotransporters are widely distributed among Gram-negative bacteria. They can have a large variety of functions and many of them have a role in virulence. They are synthesized as large precursors with an N-terminal signal sequence that mediates transport across the inner membrane via the Sec machinery and a translocator domain that mediates the transport of the connected passenger domain across the outer membrane to the bacterial cell surface. Like integral outer membrane proteins, the translocator domain folds in a β-barrel structure and requires the Bam machinery for its insertion into the outer membrane. After transport across the outer membrane, the passenger may stay connected via the translocator domain to the bacterial cell surface or it is proteolytically released into the extracellular milieu. Based on the size of the translocator domain and its position relative to the passenger in the precursor, autotransporters are divided into four sub-categories. We review here the current knowledge of the biogenesis, structure and function of various autotransporters., (Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)