Receptor-specific ubiquitination of beta-arrestin directs assembly and targeting of seven-transmembrane receptor signalosomes

J Biol Chem. 2005 Apr 15;280(15):15315-24. doi: 10.1074/jbc.M412418200. Epub 2005 Feb 7.

Abstract

Angiotensin II type 1a (AT1a), vasopressin V2, and neurokinin 1 (NK1) receptors are seven-transmembrane receptors (7TMRs) that bind and co-internalize with the multifunctional adaptor protein, beta-arrestin. These receptors also lead to robust and persistent activation of extracellular-signal regulated kinase 1/2 (ERK1/2) localized on endosomes. Recently, the co-trafficking of receptor-beta-arrestin complexes to endosomes was demonstrated to require stable beta-arrestin ubiquitination (Shenoy, S. K., and Lefkowitz, R. J. (2003) J. Biol. Chem. 278, 14498-14506). We now report that lysines at positions 11 and 12 in beta-arrestin2 are specific and required sites for its AngII-mediated sustained ubiquitination. Thus, upon AngII stimulation the mutant beta-arrestin2(K11,12R) is only transiently ubiquitinated, does not form stable endocytic complexes with the AT1aR, and is impaired in scaffolding-activated ERK1/2. Fusion of a ubiquitin moiety in-frame to beta-arrestin2(K11,12R) restores AngII-mediated trafficking and signaling. Wild type beta-arrestin2 and beta-arrestin2(K11R,K12R)-Ub, but not beta-arrestin2(K11R,K12R), prevent nuclear translocation of pERK. These findings imply that sustained beta-arrestin ubiquitination not only directs co-trafficking of receptor-beta-arrestin complexes but also orchestrates the targeting of "7TMR signalosomes" to microcompartments within the cell. Surprisingly, binding of beta-arrestin2(K11R,K12R) to V2R and NK1R is indistinguishable from that of wild type beta-arrestin2. Moreover, ubiquitination patterns and ERK scaffolding of beta-arrestin2(K11,12R) are unimpaired with respect to V2R stimulation. In contrast, a quintuple lysine mutant (beta-arrestin2(K18R,K107R,K108R,K207R,K296R)) is impaired in endosomal trafficking in response to V2R but not AT1aR stimulation. Our findings delineate a novel regulatory mechanism for 7TMR signaling, dictated by the ubiquitination of beta-arrestin on specific lysines that become accessible for modification due to the specific receptor-bound conformational states of beta-arrestin2.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Active Transport, Cell Nucleus
  • Angiotensin II / chemistry
  • Angiotensin II / metabolism
  • Animals
  • Arrestins / chemistry*
  • Arrestins / metabolism
  • COS Cells
  • Cell Line
  • Endocytosis
  • Endosomes / metabolism
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Immunoprecipitation
  • Lysine / chemistry
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Models, Genetic
  • Mutation
  • Protein Binding
  • Protein Conformation
  • Protein Transport
  • Signal Transduction
  • Ubiquitin / chemistry*
  • Ubiquitin / metabolism
  • beta-Arrestins

Substances

  • Arrestins
  • Ubiquitin
  • beta-Arrestins
  • Angiotensin II
  • Green Fluorescent Proteins
  • Extracellular Signal-Regulated MAP Kinases
  • Lysine