Integrative Phosphoproteomic and Proteomic Analysis of Candida albicans Exposed to Oxidative Stress Víctor Arribas, Ana Borrajo, María Luisa Hernáez, Raquel Martínez, Lucía Monteoliva, et al. Journal of Proteome Research, 2025 Candida albicans is an opportunistic pathogen, which has recently been included in the high-priority list of pathogenic fungi by the World Health Organization (WHO). The scarce arsenal available to treat such invasive fungal infections makes the discovery of new antifungal targets an important task. This study utilizes DDA-MS technology to investigate both the phosphoproteomics and proteomics of C. albicans during its late-stage response to oxidative stress induced by H2O2, aiming to identify key proteins involved. Phosphorylation, as an important post-translational modification, plays a crucial role in the ability of C. albicans to survive oxidative stress. Our study enabled the identification and quantification of important changes in both protein abundance and phosphorylation events across multiple proteins following a 200 min 10 mM H2O2 treatment. The use of the DDA-MS approach allowed for the identification of new actors in the response to oxidative stress. Novel phosphorylation sites were identified in kinases and transcription factors. Regarding protein kinases, Cdc5-reduced phosphorylation may mediate a transient G2 cell cycle arrest, while Kis1─the regulatory β-subunit of Snf1 kinase─might play a role in ROS scavenging following oxidative stress. In terms of transcription factors, Gzf3-decreased phosphorylation was essential for cell survival and ROS detoxification after oxidative stress.
Unravelling the Role of Candida albicans Prn1 in the Oxidative Stress Response through a Proteomics Approach Victor Arribas, Lucia Monteoliva, María Luisa Hernáez, Concha Gil, Gloria Molero Antioxidants, 2024 Candida albicans Prn1 is a protein with an unknown function similar to mammalian Pirin. It also has orthologues in other pathogenic fungi, but not in Saccharomyces cerevisiae. Prn1 highly increases its abundance in response to H2O2 treatment; thus, to study its involvement in the oxidative stress response, a C. albicans prn1∆ mutant and the corresponding wild-type strain SN250 have been studied. Under H2O2 treatment, Prn1 absence led to a higher level of reactive oxygen species (ROS) and a lower survival rate, with a higher percentage of death by apoptosis, confirming its relevant role in oxidative detoxication. The quantitative differential proteomics studies of both strains in the presence and absence of H2O2 indicated a lower increase in proteins with oxidoreductase activity after the treatment in the prn1∆ strain, as well as an increase in proteasome-activating proteins, corroborated by in vivo measurements of proteasome activity, with respect to the wild type. In addition, remarkable differences in the abundance of some transcription factors were observed between mutant and wild-type strains, e.g., Mnl1 or Nrg1, an Mnl1 antagonist. orf19.4850, a protein orthologue to S. cerevisiae Cub1, has shown its involvement in the response to H2O2 and in proteasome function when Prn1 is highly expressed in the wild type.