Discovery of a dual Ras and ARF6 inhibitor from a GPCR endocytosis screen
Jenna Giubilaro, Doris A. Schuetz, Tomasz Maciej Stępniewski, Yoon Namkung, Étienne Khoury, Mónica Lara‐Márquez, Shirley Campbell, Alexandre Beautrait, Sylvain Armando, Olivier Radresa, Jean Duchaine, Nathalie Lamarche‐Vane, Audrey Claing, Jana Selent, Michel Bouvier, Anne Marinier, Stéphane A. Laporte
Abstract
Internalization and intracellular trafficking of G protein-coupled receptors (GPCRs) play pivotal roles in cell responsiveness. Dysregulation in receptor trafficking can lead to aberrant signaling and cell behavior. Here, using an endosomal BRET-based assay in a high-throughput screen with the prototypical GPCR angiotensin II type 1 receptor (AT1R), we sought to identify receptor trafficking inhibitors from a library of ~115,000 small molecules. We identified a novel dual Ras and ARF6 inhibitor, which we named Rasarfin, that blocks agonist-mediated internalization of AT1R and other GPCRs. Rasarfin also potently inhibits agonist-induced ERK1/2 signaling by GPCRs, and MAPK and Akt signaling by EGFR, as well as prevents cancer cell proliferation. In silico modeling and in vitro studies reveal a unique binding modality of Rasarfin within the SOS-binding domain of Ras. Our findings unveil a class of dual small G protein inhibitors for receptor trafficking and signaling, useful for the inhibition of oncogenic cellular responses.