Redox Regulation of Mitochondrial Metal-Dependent Serine Threonine Phosphatase PPTc7

• Grant number: 24/20191-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Luciana Elena de Souza Fraga Machado
• Grantee: Mel Mirra de Carvalho Rachid
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Protein phosphatases are located in the cytosol and mitochondria, where they regulate several cellular functions through the dephosphorylation of their substrates, playing essential roles in processes such as the response to stress, energy metabolism, and regulation of cell progression. However, the knowledge regarding the regulatory mechanisms for mitochondrial protein phosphatases remains limited. Recent data from my scientific initiation with BCO-FAPESP scholarship showed that the activity of PPTc7 is inhibited by oxidation and recovered by the reducing agent DTT in vitro. Additionally, the ¿ptc7 yeast mutant exhibited sensibility to the oxidizing effects of hydrogen peroxide, appearing to be more resistant in glucose media and more sensitive in galactose media when compared to the wild type - as outlined in the attached scientific report. Thus, the present work aims to investigate the redox regulation of the mitochondrial serine/threonine protein phosphatase PPTc7 in vivo - a fundamental protein in activating the citrate synthase enzyme and regulating mitochondrial metabolism via CoQ10 biosynthesis modulation. To achieve this, we will complement ¿ptc7 yeast with its human homolog to assess the functional restoration. We also will quantify the oxidants production and analyze the cellular respiration in the ¿ptc7 yeast. Based on previous findings, we anticipate that ¿ptc7 yeast will recover its growth similar to the wild-type yeast when complemented with the PTc7 human homolog and that the mutant yeast will exhibit respiratory deficiency in galactose media. These experimental results will enhance our understanding of the regulatory mechanisms of the mitochondrial protein phosphatase PPTc7, contributing to further analysis of this protein.