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Candida albicans Sun41p, a putative glycosidase, is involved in morphogenesis, cell wall biogenesis, and biofilm formation

Fraunhofer Institute for Interfacial Engineering and Biotechnology, Nobelstrasse 12, 70569 Stuttgart, Germany.
Eukaryotic Cell (Impact Factor: 3.18). 12/2007; 6(11):2056-65. DOI: 10.1128/EC.00285-07
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ABSTRACT The SUN gene family has been defined in Saccharomyces cerevisiae and comprises a fungus-specific family of proteins which show high similarity in their C-terminal domains. Genes of this family are involved in different cellular processes, like DNA replication, aging, mitochondrial biogenesis, and cytokinesis. In Candida albicans the SUN family comprises two genes, SUN41 and SIM1. We demonstrate that C. albicans mutants lacking SUN41 show similar defects as found for S. cerevisiae, including defects in cytokinesis. In addition, the SUN41 mutant showed a higher sensitivity towards the cell wall-disturbing agent Congo red, whereas no difference was observed in the presence of calcofluor white. Compared to the wild type, SUN41 deletion strains exhibited a defect in biofilm formation, a reduced adherence on a Caco-2 cell monolayer, and were unable to form hyphae on solid medium under the conditions tested. Interestingly, Sun41p was found to be secreted in the medium of cells growing as blastospores as well as those forming hyphae. Our results support a function of SUN41p as a glycosidase involved in cytokinesis, cell wall biogenesis, adhesion to host tissue, and biofilm formation, indicating an important role in the host-pathogen interaction.

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Available from: Steffen Rupp, Aug 13, 2015
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    • "Interestingly, mass-spectrometry analysis of the secretome of SC5314 identified Sun41p as well as Sim1p/Sun42p as secreted proteins of cells growing as blastospores as well as those forming hyphae. This suggests that Sun41p is active at the outer rim of the cell wall (Hiller et al., 2007). In addition, in a parallel study Norice et al. (2007) could show that SUN41 indeed is required for virulence in a mouse model of systemic infection. "
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    • "Transcript profiling has identified genes that show increased or decreased expression in biofilms relative to planktonic cells and it has been hypothesized that these genes might play some role in biofilm formation. For instance, C. albicans SUN41 was among the genes that showed high upregulation upon biofilm growth (Garcia- Sanchez et al., 2004) and was subsequently shown to be required for biofilm formation, possibly through its contribution to morphogenesis and/or matrix production (Firon et al., 2007; Hiller et al., 2007; Norice et al., 2007). Yet, other examples showed no strict correlation between differential regulation in biofilm versus planktonic growth and contribution to biofilm formation (Moreno-Ruiz et al., 2009; Sellam et al., 2009). "
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    • "Importantly, of the 44 secretory proteins we were able to identify in the growth medium, only Mp65, Sun41 and Tos1 seemed to be consistently and abundantly present under all four conditions. This observation is supported by previous studies (Hiller et al., 2007; Maddi et al., 2009). The corresponding genes are highly conserved in many fungi, underlining their functional importance. "
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