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beta-arrestins regulate mitogenic signaling and clathrin-mediated endocytosis of the insulin-like growth factor I
F T Lin1, Y Daaka, R J Lefkowitz
1Howard Hughes Medical Institute, Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.
Abstract:
beta-Arrestins mediate agonist-dependent desensitization of G protein-coupled receptors and target the receptors to clathrin-coated pits for internalization. Here we report an expanded role of beta-arrestins in promoting clathrin-mediated endocytosis of a tyrosine kinase growth factor receptor, i.e. the insulin-like growth factor I (IGF-1) receptor. beta-Arrestins bind to the ligand-occupied IGF-1 receptors, promote their endocytosis, and enhance IGF-1-dependent mitogen-activated protein kinase phosphorylation and DNA synthesis. Our results suggest a role for beta-arrestins in regulating mitogenic signaling and clathrin-mediated endocytosis of receptors not classically coupled to G proteins.