Identification of select G-protein coupled receptors as regulators of the ER-mitochondria contacts by drug screening
AbstractEndoplasmic reticulum-mitochondrial (ER-Mito) contacts are crucial for many cellular functions. Their dysregulation has been implicated in various disorders including neurodegenerative, cardiovascular and metabolic diseases, and cancer. However, little is known about the regulatory pathways of ER-Mito contacts. To uncover such pathways, we screened a drug library using a split-Renilla luciferase (split-Rluc) reassembly assay in HEK293T cells. We identified multiple agonists of G-protein coupled receptors (GPCRs), beta-adrenergic receptors (β-ARs) in particular. Using multiple independent assays, we validated that these drugs enhance the physical and functional interactions between ER and mitochondria. Our data provide evidence that GPCR signal modulates ER-Mito coupling through activating EPAC (exchange protein directly activated by cAMP) and increasing cytoplasmic Ca2+ levels, and that actin polymerization, likely regulated by CDC42 upon receptor activation, is required for this coupling. Together our study identifies GPCR signaling as a regulatory mechanism for ER-Mito contacts, and highlights the role of these contacts in responding to physiological demands or stresses.