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Ubiquitination regulates proteolytic processing of G protein-coupled receptors after their sorting to lysosomes. J Biol Chem 2009 Jul 17;284(29):19361-70

Date

05/13/2009

Pubmed ID

19433584

Pubmed Central ID

PMC2740561

DOI

10.1074/jbc.M109.001644

Scopus ID

2-s2.0-67749127754   67 Citations

Abstract

Ubiquitination is essential for the endocytic sorting of various G protein-coupled receptors to lysosomes. Here we identify a distinct function of this covalent modification in controlling the later proteolytic processing of receptors. Mutation of all cytoplasmic lysine residues in the murine delta-opioid receptor blocked receptor ubiquitination without preventing ligand-induced endocytosis of receptors or their subsequent delivery to lysosomes, as verified by proteolysis of extramembrane epitope tags and down-regulation of radioligand binding to the transmembrane helices. Surprisingly, a functional screen revealed that the E3 ubiquitin ligase AIP4 specifically controls down-regulation of wild type receptors measured by radioligand binding without detectably affecting receptor delivery to lysosomes defined both immunochemically and biochemically. This specific AIP4-dependent regulation required direct ubiquitination of receptors and was also regulated by two deubiquitinating enzymes, AMSH and UBPY, which localized to late endosome/lysosome membranes containing internalized delta-opioid receptor. These results identify a distinct function of AIP4-dependent ubiquitination in controlling the later proteolytic processing of G protein-coupled receptors, without detectably affecting their endocytic sorting to lysosomes. We propose that ubiquitination or ubiquitination/deubiquitination cycling specifically regulates later proteolytic processing events required for destruction of the receptor's hydrophobic core.

Author List

Hislop JN, Henry AG, Marchese A, von Zastrow M

Author

Adriano Marchese PhD Professor in the Biochemistry department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Binding, Competitive
Biotinylation
Cell Line
Electrophoresis, Polyacrylamide Gel
Endosomes
Green Fluorescent Proteins
Humans
Immunoblotting
Lysosomes
Microscopy, Fluorescence
Models, Biological
Mutation
Protein Processing, Post-Translational
Protein Transport
Radioligand Assay
Receptors, G-Protein-Coupled
Recombinant Fusion Proteins
Transfection
Ubiquitin
Ubiquitin-Protein Ligases
Ubiquitination