Use of proximity biotinylation to identify protein disulfide isomerase A3 interactors during neuronal differentiation

• Grant number: 25/10600-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Danilo Bilches Medinas
• Grantee: Ana Luiza Lourenço Gonçalves
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/06287-6 - Role of protein disulfide isomerase A3 in learning and memory, AP.JP

Abstract

Protein disulfide isomerases (PDIs) are enzymes of the endoplasmic reticulum containing thioredoxin domains that catalyze protein folding through the formation of disulfide bonds between cysteine residues. This process, which we refer to as redox folding, is essential for the structural stability of proteins, as well as for the regulation of their functions. Failure in redox folding has been associated with numerous pathologies, among which we highlight neurological diseases. Genetic, biochemical and histopathological evidence indicate that PDIs dysfunction participates in pathogenic mechanisms in neurons, leading to loss of neuronal connectivity and viability. Studies from our laboratory have contributed to elucidate the involvement of PDIA3, an evolutionarily conserved paralog of the PDIs family, in neuronal morphogenesis and synapse formation. However, the substrates of PDIA3 in developing neurons are still unknown. In this proposal, we will use proximity biotinylation to label interactors of PDIA3 and its mutant form associated with intellectual disability, followed by mass spectrometry for protein identification. Possible PDIA3 substrates important for neuronal differentiation will be determined through bioinformatic analysis of interactors that contain disulfide bonds and are distributed in the plasma membrane. The development of this proposal will generate critical knowledge for the understanding of neuronal morphogenesis and possible alterations in this process that lead to cognitive problems. (AU)