Regulation of the E3 Ligase WWP2 by GPCR Activation and CDH1 Mediates ALIXdependent Lysosomal Sorting

Abstract

G protein‐coupled receptors (GPCRs) comprise the largest and most diverse family of membrane receptors. Dysregulated GPCR signaling is linked to multiple diseases, including inflammation, vascular disease, and many cancers. Attenuation of GPCR signaling is mediated by internalization and lysosomal degradation. GPCRs signal to their endocytic sorting machinery to initiate trafficking at the plasma membrane as well as at the limiting membrane of early and late endosomes. GPCRs like protease‐activated receptor 1 (PAR1) can stimulate the ubiquitination and activation of ALIX, an adaptor protein that sorts GPCRs with intracellular YPXnL motifs into budding intraluminal vesicles at multivesicular endosomes. This process is mediated by the NEDD4‐family E3 ubiquitin ligase WWP2. Here, we show that stimulation of multiple YPXnL‐motif receptors, including PAR1, the purinergic receptor P2Y1 and the histamine H2 receptor, induce ubiquitination of WWP2 during receptor lysosomal sorting. In addition, we have identified a novel role for the E3 ligase CDH1 in modulating WWP2 ubiquitination. Transient depletion of CDH1 leads to elevated WWP2 ubiquitination and receptor downregulation, suggesting a potential mechanism for conditionally modulating WWP2 activity during receptor trafficking. Our current research aims to elucidate the common connection between the signaling pathways activated by YPXnL GPCRs and the regulation of CDH1 and WWP2.