The role of ubiquitination in lysosomal trafficking of δ-opioid receptors

Anastasia G. Henry, Ian J. White, Mark Marsh, Mark von Zastrow*, James N. Hislop

*Corresponding author for this work

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

The δ-opioid receptor (DOR) undergoes ligand-induced downregulation by endosomal sorting complex required for transport (ESCRT)-dependent endocytic trafficking to lysosomes. In contrast to a number of other signaling receptors, the DOR can downregulate effectively when its ubiquitination is prevented. We explored the membrane trafficking basis of this behavior. First, we show that internalized DORs traverse the canonical multivesicular body (MVB) pathway and localize to intralumenal vesicles (ILVs). Second, we show that DOR ubiquitination stimulates, but is not essential for, receptor transfer to ILVs and proteolysis of the receptor endodomain. Third, we show that receptor ubiquitination plays no detectable role in the early sorting of internalized DORs out of the recycling pathway. Finally, we show that DORs undergo extensive proteolytic fragmentation in the ectodomain, even when receptor ubiquitination is prevented or ILV formation itself is blocked. Together, these results are sufficient to explain why DORs downregulate effectively in the absence of ubiquitination, and they place a discrete molecular sorting operation in the MVB pathway effectively upstream of the ESCRT. More generally, these findings support the hypothesis that mammalian cells can control the cytoplasmic accessibility of internalized signaling receptors independently from their ultimate trafficking fate.

Original languageEnglish
Pages (from-to)170-184
Number of pages15
JournalTraffic
Volume12
Issue number2
Early online date22 Dec 2010
DOIs
Publication statusPublished - Feb 2011

Keywords

  • down-regulation
  • multivesicular endosomes
  • mediates ubiquitination
  • binding proteins
  • ligase AIP4
  • protein-coupled receptor
  • ubiquitin
  • molecular-mechanisms
  • GPCR
  • sorting proteins
  • membrane
  • microscopy
  • recycling pathway
  • sorting

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