PMID:19389762

Citation	Zhang, L, Feng, D, Fang, W, Ouyang, H, Luo, Y, Du, T and Jin, C (2009) Comparative proteomic analysis of an Aspergillus fumigatus mutant deficient in glucosidase I (AfCwh41). Microbiology (Reading, Engl.) 155:2157-67
Abstract	Alpha-glucosidase I regulates trimming of the terminal alpha-1,2-glucose residue in the N-glycan processing pathway, which plays an important role in quality control systems in mammalian cells. Previously, we identified the gene encoding alpha-glucosidase I in the opportunistic human fungal pathogen Aspergillus fumigatus, namely Afcwh41. Deletion of the Afcwh41 gene results in a severe reduction of conidia formation, a temperature-sensitive deficiency of cell wall integrity, and abnormalities of polar growth and septation. An upregulation of the genes encoding Rho-type GTPases was also observed, which suggests activation of the cell wall integrity pathway in the mutant. Using 2D gel analysis, we revealed that the proteins involved in protein assembly, ubiquitin-mediated degradation and actin organization are altered in the DeltaAfcwh41 mutant. Evidence was obtained for a defect in the polarized localization of the actin cytoskeleton in the mutant. Our results suggest that blocking of the glucose trimming in A. fumigatus might induce accumulation of misfolded proteins in the endoplasmic reticulum; these misfolded proteins are probably required for cell wall synthesis and thus activate the cell wall integrity pathway, which then causes the abnormal polarity associated with the DeltaAfcwh41 mutant.
Links	PubMed Online version:10.1099/mic.0.027490-0
Keywords	Actins/metabolism; Aspergillus fumigatus/drug effects; Aspergillus fumigatus/physiology; Calnexin/biosynthesis; Cell Polarity; Cell Wall/metabolism; Dithiothreitol/pharmacology; Electrophoresis, Gel, Two-Dimensional; Endoplasmic Reticulum/drug effects; Fungal Proteins/biosynthesis; Microfilament Proteins/biosynthesis; Protein Folding; Proteome/analysis; Spores, Fungal/metabolism; Tandem Mass Spectrometry; alpha-Glucosidases/deficiency; rho GTP-Binding Proteins/biosynthesis
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ASPFM:Q6S9W4		GO:0030010: establishment of cell polarity	ECO:0000315:		P		Fig. 4 shows that the wildtype has an accumulation of actin patches at the poles whereas the mutant has actin patches evenly distributed throughout.	complete CACAO 4874

References

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