Small ubiquitin-like modifier modification of arrestin-3 regulates receptor trafficking.

ABSTRACT: Nonvisual arrestins are regulated by direct post-translational modifications, such as phosphorylation, ubiquitination, and nitrosylation. However, whether arrestins are regulated by other post-translational modifications remains unknown. Here we show that nonvisual arrestins are modified by small ubiquitin-like modifier 1 (SUMO-1) upon activation of ?(2)-adrenergic receptor (?(2)AR). Lysine residues 295 and 400 in arrestin-3 fall within canonical SUMO consensus sites, and mutagenic analysis reveals that Lys-400 represents the main SUMOylation site. Depletion of the SUMO E2 modifying enzyme Ubc9 blocks arrestin-3 SUMOylation and attenuates ?(2)AR internalization, suggesting that arrestin SUMOylation mediates G protein-coupled receptor endocytosis. Consistent with this, expression of a SUMO-deficient arrestin mutant failed to promote ?(2)AR internalization as compared with wild-type arrestin-3. Our data reveal an unprecedented role for SUMOylation in mediating GPCR endocytosis and provide novel mechanistic insight into arrestin function and regulation.

SUBMITTER: Wyatt D 

PROVIDER: S-EPMC3030389 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature