Assays of adrenal GPCR signaling and regulation: Measuring adrenal β-arrestin activity in vivo through plasma membrane recruitment.

Production and secretion of catecholamines and aldosterone from the adrenal gland are regulated by various adrenal G protein-coupled receptors (GPCRs), including α2-adrenergic (auto)receptors (ARs) and angiotensin receptors. These hormones, in turn, regulate cardiac function and play important pathophysiological roles in heart failure (HF). Recent studies have identified the GPCR adapter proteins β-arrestins, specifically β-arrestin1, as an important mediator of the GPCR-dependent production of these hormones in the adrenal gland. Upon GPCR agonist activation, β-arrestins translocate from the cytoplasm to the plasma membrane to interact with the phosphorylated and active receptor and mediate its G protein-independent signaling. Here, we describe a simple and fast Western blotting-based technique for measuring adrenal β-arrestin plasma membrane recruitment in vivo, as an (indirect) index of its activity toward various agonist-activated adrenal GPCRs in vivo.