High molecular weight protein complexes involving protein disulfide isomerases: a window towards novel redox signaling mechanisms

• Grant number: 20/02253-7
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): February 01, 2021
• Effective date (End): May 12, 2021
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Francisco Rafael Martins Laurindo
• Grantee: Zeinab Ghasemishahrestani
• 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
• Associated research grant: 13/07937-8 - Redoxome - Redox Processes in Biomedicine, AP.CEPID

Abstract

High Molecular Weight Protein Complexes (HMW-PCs) are important effectors and regulators of cell signaling by constituting important hubs in protein-protein interaction networks. Therefore, the detection and analysis of HMW-PCs in distinct physiological conditions can provide windows to uncover novel and unexpected signaling routes related to major cell functions. Redox-related proteins and chaperones are specially poised to nucleate HMW-PC. Protein disulfide isomerases, particularly its prototype PDIA1, are dithiol-disulfide oxidoreductase chaperones from thioredoxin superfamily. PDIA1 is canonically located at the endoplasmic reticulum, exerting essential functions in disulfide bond introduction and protein folding. We have described additional PDIA1 functions in redox signaling at distinct cellular locations. PDI functions are consistent with their potential roles in HMW-PC nucleation or stabilization. We propose that PDIs (in particular PDIA1) undergo thiol redox-dependent stable HMW-PC formation as converging signaling hubs involved in (patho)physiological mechanisms. The underlying hypothesis is that under a variety of environmental cues, e.g., mechanostimuli, vascular endothelial and smooth muscle cells respond by forming PDI-containing HMW-PC in a redox-dependent fashion, either in the ER or at other cellular locations. The purpose of such HMW-PC would be to organize cell signaling responses. The overall aim of this project is to detect, analyze and assess the physiological significance of HMW protein complexes (HMW-PC) involving PDI(s) in vascular cells. The specific aims are: 1) To search for HMW-PCs containing PDIA1 in vascular cells exposed to distinct conditions, in particular endothelial cells exposed to shear stress and Vascular Smooth Muscle Cells (VSMC) exposed to cyclic stretch; 2) To investigate the thiol redox susceptibility and subcellular localization of HMW-PCs containing PDIA1; 3) To retrieve the most relevant PDIA1-containing HMW-PC(s) and determine its (their) composition by mass spectrometry analysis; 4) Search for evidence related to possible physiological implications of PDI-containing HMW-PC. These results may reveal novel molecular pathways involved in mechanistic routes associated with PDIs, potentially related to their multiple vascular effects. (AU)