Tetraspan cargo adaptors usher GPI-anchored proteins into multivesicular bodies

Chris MacDonald, Mark A. Stamnes, David J. Katzmann, Robert C. Piper

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Ubiquitinated membrane proteins are sorted into intralumenal endosomal vesicles on their way for degradation in lysosomes. Here we summarize the discovery of the Cos proteins, which work to organize and segregate ubiquitinated cargo prior to its incorporation into intralumenal vesicles of the multivesicular body (MVB). Importantly, cargoes such as GPI-anchored proteins (GPIAPs) that cannot undergo ubiquitination, rely entirely on Cos proteins for sorting into intralumenal vesicles using the same pathway that depends on ESCRTs and ubiquitin ligases that typical polytopic membrane proteins do. Here we show Cos proteins provide functions as not only adaptor proteins for ubiquitin ligases, but also as cargo carriers that can physically usher a variety of other proteins into the MVB pathway. We then discuss the significance of this new sorting model and the broader implications for this cargo adaptor mechanism, whereby yeast Cos proteins, and their likely animal analogs, provide a ubiquitin sorting signal in trans to enable sorting of a membrane protein network into intralumenal vesicles.

Original languageEnglish (US)
Pages (from-to)3673-3678
Number of pages6
JournalCell Cycle
Volume14
Issue number23
DOIs
StatePublished - Jan 1 2015

Keywords

  • Cos proteins
  • GPI-anchored proteins
  • Lysosomes
  • Multivesicular bodies
  • Tetraspanins
  • Ubiquitin
  • Vacuole

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology

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