title: Kexin-like endoprotease KexB is required for N-glycan processing, morphogenesis and virulence in Aspergillus fumigatus.
abstract: Kexin-like proteins belong to the subtilisin-like family of the proteinases that cleave secretory proproteins to their active forms. Several fungal kexin-like proteins have been investigated. The mutants lacking of kexin-like protein display strong phenotypes such as cell wall defect, abnormal polarity, and, in case of Candida albicans, diminished virulence. However, only several proteins have been confirmed as the substrates of kexin-like proteases in these fungal species. It still remains unclear how kexin-like proteins contribute to the morphogenesis in these fungal species. In this study, a kexB-null mutant of the human opportunistic fungal pathogen Aspergillus fumigatus was constructed and analyzed. The ΔkexB mutant showed retarded growth, temperature-sensitive cell wall defect, reduced conidia formation, and abnormal polarity. Biochemical analyses revealed that deletion of the kexB gene resulted in impaired N-glycan processing, activation of the MpkA-dependent cell wall integrity signaling pathway, and ER-stress. Results from in vivo assays demonstrated that the mutant exhibited an attenuated virulence in immunecompromised mice. Based on our results, the kexin-like endoprotease KexB was involved in the N-glycan processing, which provides a novel insight to understand how kexin-like protein affects the cell-wall modifying enzymes and therefore morphogenesis in fungi.
authors: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, China.
authors: Jingyang
authors: J
authors: Wang
authors: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Hui
authors: H
authors: Zhou
authors: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Hua
authors: H
authors: Lu
authors: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Ting
authors: T
authors: Du
authors: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Yuanming
authors: Y
authors: Luo
authors: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna A-1190, Austria.
authors: Iain B H
authors: IB
authors: Wilson
authors: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: jinc@im.ac.cn.
authors: Cheng
authors: C
authors: Jin
mesh_terms: D000818:Animals; D001232:Aspergillus fumigatus / Q000166:cytology / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D005656:Fungal Proteins / Q000378:metabolism*; D051379:Mice; D009024:Morphogenesis; D009154:Mutation; D010447:Peptide Hydrolases / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D014774:Virulence
chemical_list: D005656:Fungal Proteins; D011134:Polysaccharides; D010447:Peptide Hydrolases
keywords: Aspergillus fumigatus; Kexin-like protease; Morphogenesis; N-glycan processing; Virulence