A Family of Tetraspans Organizes Cargo for Sorting into Multivesicular Bodies

Chris MacDonald, Johanna A. Payne, Mariam Aboian, William Smith, David J. Katzmann, Robert C. Piper

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

The abundance of cell-surface membrane proteins isregulated by internalization and delivery into intralumenal vesicles (ILVs) of multivesicular bodies (MVBs). Many cargoes are ubiquitinated, allowing access to an ESCRT-dependent pathway into MVBs. Yet how nonubiquitinated proteins, such as glycosylphosphatidylinositol-anchored proteins, enter MVBs is unclear, supporting the possibility of mechanistically distinct ILV biogenesis pathways. Here we show that a family of highly ubiquitinated tetraspan Cos proteins provides a Ub signal in trans, allowing sorting of nonubiquitinated MVB cargo into the canonical ESCRT- and Ub-dependent pathway. Cos proteins create discrete endosomal subdomains that concentrate Ub cargo prior to their envelopment into ILVs, and the activity of Cos proteins is required not only for efficient sorting of canonical Ub cargo but also for sorting nonubiquitinated cargo into MVBs. Expression of these proteins increases during nutrient stress through an NAD+/Sir2-dependent mechanism that in turn accelerates the downregulation of a broad range of cell-surface proteins.

Original languageEnglish (US)
Pages (from-to)328-342
Number of pages15
JournalDevelopmental Cell
Volume33
Issue number3
DOIs
StatePublished - May 4 2015

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Developmental Biology
  • Cell Biology

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