Physico-chemical assessment of the interaction between protein disulfide isomerase-A1 and Rho-guanine dissociation inhibitor-a

• Grant number: 23/00863-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: August 01, 2023
• End date: July 31, 2024
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Francisco Rafael Martins Laurindo
• Grantee: Gabriele Verônica de Mello Gabriel
• Supervisor: Sharon Campbell
• Host Institution: Instituto do Coração Professor Euryclides de Jesus Zerbini (INCOR). Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Institution abroad: University of North Carolina at Chapel Hill (UNC), United States
• Associated to the scholarship: 20/11206-2 - Interaction between protein dissulfide isomerase-A1 (PDIA1) and RhoGDI (guanine nucleotide dissociation inhibitor)-a: new frontier in RhoGTPases redox regulation and cellular remodeling, BP.PD

Abstract

PDIA1 is a redox chaperone from thioredoxin superfamily with roles on redox protein folding in the endoplasmic reticulum. Work from our group has suggested additional redox signaling roles for PDIA1 (the PDI family prototype) related to the regulation of the cytoskeleton and signaling by RhoGTPases and their regulators such as RhoGDIs. In this context, we propose that the interaction between PDIA1 and RhoGDIa can be hub of important, potentially redox-dependent, molecular signals affecting RhoGTPase and cytoskeletal regulation. We collected significant evidences that PDIA1 interacts with RhoGDIa, including co-localization, co-immunoprecipitation and proximity ligation assays. In the context of our current post-doctoral project, we obtained additional evidences, including bimolecular fluorescence complementation assays and ELISA assays with specific PDIA1 domains. These data are further supported by molecular dynamic simulation models. However, such results are not yet unambiguous and further characterization of the PDIA1/RhoGDIa interaction would be desirable, particularly using more specific physico-chemical tools to unravel additional details of the molecular mechanisms involved in this interaction. Furthermore, whether post-translational mechanisms modulate such interaction is unclear. Finally, the effect of PDIA1 on the selective binding of RhoGDIa to specific RhoGTPases, although suggested by molecular dynamic simulations, is unproven. Thus, the specific aims of our BEPE project are: 1) To further probe the interaction between PDIA1 and RhoGDIa and to identify specific residues involved; 2) To address the roles of redox post-translational PDIA1 modifications in its interaction with RhoGDIa; 3) To analyze possible selective interference of PDIA1 in the binding of RhoGDIa to RhoA, Rac1 or Cdc42. Exploring these structural/molecular details is essential to allow future testing of the functional relevance of PDIA1/RhoGDIa interaction in cellular remodeling and pathophysiological situations. (AU)