title: Tfp1 is required for ion homeostasis, fluconazole resistance and N-Acetylglucosamine utilization in Candida albicans.
abstract: The vacuolar-type H+-ATPase (V-ATPase) is crucial for the maintenance of ion homeostasis. Dysregulation of ion homeostasis affects various aspects of cellular processes. However, the importance of V-ATPase in Candida albicans is not totally clear. In this study, we demonstrated the essential roles of V-ATPase through Tfp1, a putative V-ATPase subunit. Deletion of TFP1 led to generation of an iron starvation signal and reduced total iron content, which was associated with mislocalization of Fet34p that was finally due to disorders in copper homeostasis. Furthermore, the tfp1∆/∆ mutant exhibited weaker growth and lower aconitase activity on nonfermentable carbon sources, and iron or copper addition partially rescued the growth defect. In addition, the tfp1∆/∆ mutant also showed elevated cytosolic calcium levels in normal or low calcium medium that were relevant to calcium release from vacuole. Kinetics of cytosolic calcium response to an alkaline pulse and VCX1 (VCX1 encodes a putative vacuolar Ca2+/H+ exchanger) overexpression assays indicated that the cytosolic calcium status was in relation to Vcx1 activity. Spot assay and concentration-kill curve demonstrated that the tfp1∆/∆ mutant was hypersensitive to fluconazole, which was attributed to reduced ergosterol biosynthesis and CDR1 efflux pump activity, and iron/calcium dysregulation. Interestingly, carbon source utilization tests found the tfp1∆/∆ mutant was defective for growth on N-Acetylglucosamine (GlcNAc) plate, which was associated with ATP depletion due to the decreased ability to catabolize GlcNAc. Taken together, our study gives new insights into functions of Tfp1, and provides the potential to better exploit V-ATPase as an antifungal target.
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Jia
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Qilin
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Chenpeng
authors.initials: C
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Yijie
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Yulu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Laijun
authors.initials: L
authors.lastname: Xing
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China. Electronic address: nklimingchun@163.com.
authors.forename: Mingchun
authors.initials: M
authors.lastname: Li
mesh_terms: D000117:Acetylglucosamine / Q000235:genetics / Q000378:metabolism*; D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000201:enzymology* / Q000235:genetics; D025141:Drug Resistance, Fungal / Q000187:drug effects* / Q000235:genetics; D015725:Fluconazole / Q000494:pharmacology*; D017136:Ion Transport / Q000187:drug effects / Q000235:genetics; D009154:Mutation; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D015725:Fluconazole; D006180:Proton-Translocating ATPases; D000117:Acetylglucosamine
keywords: Candida albicans; Fluconazole; GlcNAc; Ion homeostasis; Tfp1; V-ATPase