Open AccessWsp1, a GBD/CRIB Domain-Containing WASP Homolog, Is Required for Growth, Morphogenesis, and Virulence of Cryptococcus neoformans
Author(s) -
Guanghui Shen,
Amy Whittington,
Ping Wang
Publication year - 2011
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.00274-10
Subject(s) - biology , endocytic cycle , microbiology and biotechnology , wiskott–aldrich syndrome protein , cryptococcus neoformans , cytokinesis , gtpase , virulence , actin cytoskeleton , septin , saccharomyces cerevisiae , fungal protein , endocytosis , appressorium , mutant , effector , cdc42 , cytoskeleton , biochemistry , yeast , gene , cell division , cell
Human endocytic protein ITSN1 regulates actin reorganization by activating Rho family GTPases, such as Cdc42. The process is enhanced by ITSN binding of WASP, an effector of Cdc42 and a potent activator of actin polymerization. In the human pathogenCryptococcus neoformans , endocytic protein Cin1 also interacts with Cdc42 and Wsp1, an uncharacterized WASP homolog, but the significance of these interactions remains unknown. Wsp1 contains several conserved domains, including a WASP homology 1 domain (WH1), a GTPase binding/Cdc42 and Rac interactive binding domain (GBD/CRIB), and a C-terminal domain composed of verprolin-like, central, and acidic motifs (VCA). Thus, Wsp1 exhibits domain compositions more similar to human WASP proteins thanSaccharomyces cerevisiae Las17/Bee1, a WASP homolog lacking the GDB/CRIB domain. Wsp1 is not an essential protein; however, thewsp1 mutant exhibited defects in growth, cytokinesis, chitin distribution, and endocytosis and exocytosis. Thewsp1 mutant was also unable to undergo genetic cross, produce the polysaccharide capsule, or secrete the enzyme urease. Anin vitro phagocytosis assay showed a higher phagocytic index for thewsp1 mutant, whose ability to cause lethal infection in a murine model of cryptococcosis was also attenuated. Our studies reveal divergent evolution of WASP proteins in the fungal phylum and suggest that the conserved function of WASP proteins in the actin cytoskeleton may also impact fungal virulence.