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

PLoS Pathog. 2021 Feb 25;17(2):e1009355. doi: 10.1371/journal.ppat.1009355. eCollection 2021 Feb.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aspartic Acid Proteases / metabolism*
  • Benzoquinones / pharmacology
  • Candida glabrata / drug effects
  • Candida glabrata / genetics
  • Candida glabrata / growth & development
  • Candida glabrata / metabolism*
  • Candidiasis / drug therapy
  • Candidiasis / metabolism
  • Candidiasis / microbiology*
  • Female
  • Flavodoxin / chemistry
  • Fungal Proteins / chemistry*
  • Fungal Proteins / metabolism*
  • Gene Expression Regulation, Fungal / drug effects*
  • Indicators and Reagents / pharmacology
  • Mice
  • Mice, Inbred BALB C
  • NAD(P)H Dehydrogenase (Quinone) / metabolism
  • Oxidation-Reduction
  • Oxidative Stress*
  • Protein Conformation
  • Vitamin K 3 / pharmacology
  • Vitamins / pharmacology


  • Benzoquinones
  • Flavodoxin
  • Fungal Proteins
  • Indicators and Reagents
  • Vitamins
  • quinone
  • Vitamin K 3
  • NAD(P)H Dehydrogenase (Quinone)
  • Aspartic Acid Proteases