An aspartyl protease-mediated cleavage regulates structure and function of a flavodoxin-like protein and aids oxidative stress survival

• Published in: PLoS pathogens 2021-02, Vol.17 (2), p.e1009355
• Main Authors: Battu, Anamika, Purushotham, Rajaram, Dey, Partha, Vamshi, S Surya, Kaur, Rupinder
• Format: Article
• Language: English
• Subjects: Adhesins; Animals; Antioxidants; Aspartic Acid Proteases - metabolism; Aspartic endopeptidase; Benzoquinones - pharmacology; Binding sites; Biology and Life Sciences; Candida glabrata - drug effects; Candida glabrata - genetics; Candida glabrata - growth & development; Candida glabrata - metabolism; Candidiasis - drug therapy; Candidiasis - metabolism; Candidiasis - microbiology; Cell surface; Chromatin; Female; Flavodoxin; Flavodoxin - chemistry; Fungal Proteins - chemistry; Fungal Proteins - metabolism; Gene Expression Regulation, Fungal - drug effects; Glutathione; Hydrogen peroxide; Indicators and Reagents - pharmacology; Infections; Inflammasomes; Intracellular; Intracellular levels; Kinases; Lipopolysaccharides; Macrophages; Medicine and Health Sciences; Menadione; Metabolic pathways; Mice; Mice, Inbred BALB C; NAD(P)H Dehydrogenase (Quinone) - metabolism; Oxidation-Reduction; Oxidative Stress; Pathways; Protein Conformation; Protein-tyrosine kinase; Proteins; Redox properties; Research and Analysis Methods; Saccharomyces cerevisiae; Spleen; Statistical analysis; Structure-function relationships; Superoxide; Survival; Syk protein; Tyrosine; Virulence; Vitamin K 3 - pharmacology; Vitamins - pharmacology
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1009355

A family of eleven glycosylphosphatidylinositol-anchored aspartyl proteases, commonly referred to as CgYapsins, regulate a myriad of cellular processes in the pathogenic yeast Candida glabrata, but their protein targets are largely unknown. Here, using the immunoprecipitation-mass spectrometry approach, we identify the flavodoxin-like protein (Fld-LP), CgPst2, to be an interactor of one of the aspartyl protease CgYps1. We also report the presence of four Fld-LPs in C. glabrata, which are required for survival in kidneys in the murine model of systemic candidiasis. We further demonstrated that of four Fld-LPs, CgPst2 was solely required for menadione detoxification. CgPst2 was found to form homo-oligomers, and contribute to cellular NADH:quinone oxidoreductase activity. CgYps1 cleaved CgPst2 at the C-terminus, and this cleavage was pivotal to oligomerization, activity and function of CgPst2. The arginine-174 residue in CgPst2 was essential for CgYps1-mediated cleavage, with alanine substitution of the arginine-174 residue also leading to elevated activity and oligomerization of CgPst2. Finally, we demonstrate that menadione treatment led to increased CgPst2 and CgYps1 protein levels, diminished CgYps1-CgPst2 interaction, and enhanced CgPst2 cleavage and activity, thereby implicating CgYps1 in activating CgPst2. Altogether, our findings of proteolytic cleavage as a key regulatory determinant of CgPst2, which belongs to the family of highly conserved, electron-carrier flavodoxin-fold-containing proteins, constituting cellular oxidative stress defense system in diverse organisms, unveil a hidden regulatory layer of environmental stress response mechanisms.