A mechanism for retromer endosomal coat complex assembly with cargo

Proc Natl Acad Sci U S A. 2014 Jan 7;111(1):267-72. doi: 10.1073/pnas.1316482111. Epub 2013 Dec 16.

Abstract

Retromer is an evolutionarily conserved protein complex composed of the VPS26, VPS29, and VPS35 proteins that selects and packages cargo proteins into transport carriers that export cargo from the endosome. The mechanisms by which retromer is recruited to the endosome and captures cargo are unknown. We show that membrane recruitment of retromer is mediated by bivalent recognition of an effector of PI3K, SNX3, and the RAB7A GTPase, by the VPS35 retromer subunit. These bivalent interactions prime retromer to capture integral membrane cargo, which enhances membrane association of retromer and initiates cargo sorting. The role of RAB7A is severely impaired by a mutation, K157N, that causes Charcot-Marie-Tooth neuropathy 2B. The results elucidate minimal requirements for retromer assembly on the endosome membrane and reveal how PI3K and RAB signaling are coupled to initiate retromer-mediated cargo export.

Keywords: biochemical reconstitution; mass spectrometry; proteoliposome; sorting nexin.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Biological Transport
  • Carrier Proteins / chemistry
  • Cross-Linking Reagents
  • Endosomes / metabolism*
  • Humans
  • Liposomes / chemistry
  • Mass Spectrometry
  • Mutation
  • Phosphatidylinositol 3-Kinases / metabolism
  • Protein Binding
  • Protein Transport
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry
  • Signal Transduction
  • Sorting Nexins / chemistry
  • Vesicular Transport Proteins / chemistry*
  • rab GTP-Binding Proteins / chemistry
  • rab7 GTP-Binding Proteins

Substances

  • Carrier Proteins
  • Cross-Linking Reagents
  • Liposomes
  • PEP8 protein, S cerevisiae
  • SNX3 protein, S cerevisiae
  • SNX3 protein, human
  • Saccharomyces cerevisiae Proteins
  • Sorting Nexins
  • VPS26A protein, human
  • VPS29 protein, S cerevisiae
  • VPS29 protein, human
  • VPS35 protein, S cerevisiae
  • VPS35 protein, human
  • Vesicular Transport Proteins
  • rab7 GTP-Binding Proteins
  • rab GTP-Binding Proteins