Discovery of a dual Ras and ARF6 inhibitor from a GPCR endocytosis screen

Abstract Internalization and intracellular trafficking of G protein-coupled receptors (GPCRs) play pivotal roles in cell responsiveness. Dysregulation receptor can lead to aberrant signaling behavior. Here, using an endosomal BRET-based assay a high-throughput screen with the prototypical GPCR angiotensin II type 1 (AT1R), we sought identify inhibitors from library ~115,000 small molecules. We identified novel dual Ras ARF6 inhibitor, which named Rasarfin, that blocks agonist-mediated internalization AT1R other GPCRs. Rasarfin also potently inhibits agonist-induced ERK1/2 by GPCRs, MAPK Akt EGFR, as well prevents cancer proliferation. In silico modeling vitro studies reveal unique binding modality within SOS-binding domain Ras. Our findings unveil class protein for signaling, useful inhibition oncogenic cellular responses.