Beta Arrestin 1 is a member of a family of proteins that are widely expressed but especially abundant in the central nervous system. Serving as an adaptor or scaffold molecule, beta Arrestin 1 is essential for mitogenic signaling. It mediates agonist dependent desensitization and internalization of G protein coupled receptors (GPCRs, e.g., beta 2 adrenergic receptor). After binding to their ligand and interacting with heterotrimeric G proteins, GPCRs are phosphorylated by G protein receptor k