Unveiling the Mediating Role of the REJ Region: PC1 and Extracellular Matrix Dynamics in ADPKD

Abstract

Objective: This study aimed to investigate the interactions of PC1 with extracellular matrix proteins (ECM) to gain insights into its role in ADPKD onset. This exploration objective is to unravel the significance of these interactions in both the healthy development of kidneys and the underlying mechanisms of ADPKD, potentially identifying therapeutic targets. Methods: We cloned and expressed the receptor of the egg jelly (REJ) domain as a maltose-binding protein-fusion protein (PET21-MBP(TEV)-REJ). Subsequently, we utilized this construct in a pulldown assay involving HEK 293 cells. In vitro, pull-down assays were conducted to evaluate the binding of the REJ fusion to various ECM components. Results: The REJ fusion protein effectively binds to vitronectin, Fibulin-1, and actin filament-associated protein (AFAP) 1. These findings indicate that the REJ region acts as a mediator for the interaction between polycystin-1 and the ECM, shedding light on the functional role of polycystin-1 in both cell-matrix and cell-cell interactions. Conclusion: The detailed characterization of REJ-ECM interactions offers a valuable foundation for future research aimed at systematically studying the effects of disease-causing mutations within the REJ module of human PC-1.