title: The Gβ-like protein CpcB is required for hyphal growth, conidiophore morphology and pathogenicity in Aspergillus fumigatus.
abstract: CpcB (cross pathway control B) encodes a yeast Cpc2 and mammalian RACK1 (receptor for activated protein kinase C) ortholog, which is a WD repeat protein with functional homology to the β subunit of heterotrimeric G proteins in Aspergillus fumigatus. Previous study has reported that CpcB governs growth and development in both A. fumigatus and Aspergillus nidulans. However, little is known about the functional identities of CpcB orthologs and their relationships with G protein complexes. In this study, we verified that cytoplasmic AfCpcB acts as a Gβ-like protein ortholog and plays important roles in hyphal growth, conidiophore morphology, cell wall integrity, and virulence in A. fumigatus. Furthermore, double deletion of AfcpcB and AfgpaB (Gα) causes a similar phenotype to AfgpaB mutant with abnormal multiple septa conidiophores but exhibits sparse conidiation with white and fluffy colonies. Thus, the exacerbated conidiation defect suggests that AfcpcB has its own specific function compared to the Gα subunit of AfgpaB or the G-protein complex. In addition, complementation assays using AfcpcB orthologs of A. nidulans and yeasts (Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans) suggest that all tested fungal AfcpcB orthologs under the A. fumigatus native promoter can largely restore hyphal growth defects in AfcpcB deletion mutant, but only the A. nidulans cpcB ortholog completely rescues the ΔAfcpcB conidiation defect, suggesting that CpcB acts as a Gβ-like protein ortholog in the Aspergilli, but may have unique and important unexplored functions that required for conidiation, which is absent in yeast.
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Zhen-dong
authors.initials: ZD
authors.lastname: Cai
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Yan-fei
authors.initials: YF
authors.lastname: Chai
authors.affiliation: Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210023, China.
authors.forename: Cai-yun
authors.initials: CY
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Wei-ran
authors.initials: WR
authors.lastname: Qiao
authors.affiliation: Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210023, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Sang
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China. Electronic address: linglu@njnu.edu.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Lu
mesh_terms: D001232:Aspergillus fumigatus / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005816:Genetic Complementation Test; D025301:Hyphae / Q000254:growth & development*; D013172:Spores, Fungal / Q000254:growth & development*
chemical_list: D019204:GTP-Binding Proteins
keywords: Aspergillus fumigatus; Conidiation; CpcB; GpaB; Gβ-like protein; Virulence