title: A mechanism for retromer endosomal coat complex assembly with cargo.
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.
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Harrison
authors.forename: Chia-Sui
authors.initials: CS
authors.lastname: Hung
authors.forename: Ting-ting
authors.initials: TT
authors.lastname: Liu
authors.forename: Romain
authors.initials: R
authors.lastname: Christiano
authors.forename: Tobias C
authors.initials: TC
authors.lastname: Walther
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Burd
mesh_terms: D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry; D003432:Cross-Linking Reagents; D011992:Endosomes / Q000378:metabolism*; D006801:Humans; D008081:Liposomes / Q000737:chemistry; D013058:Mass Spectrometry; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D015398:Signal Transduction; D058305:Sorting Nexins / Q000737:chemistry; D033921:Vesicular Transport Proteins / Q000737:chemistry*; D020691:rab GTP-Binding Proteins / Q000737:chemistry; D000090802:rab7 GTP-Binding Proteins
chemical_list: D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D008081:Liposomes; D019869:Phosphatidylinositol 3-Kinases; D029701:Saccharomyces cerevisiae Proteins; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins; D000090802:rab7 GTP-Binding Proteins; C089990:PEP8 protein, S cerevisiae; C110673:SNX3 protein, S cerevisiae; C513980:SNX3 protein, human; C498296:VPS26A protein, human; C416672:VPS29 protein, S cerevisiae; C419572:VPS29 protein, human; C076106:VPS35 protein, S cerevisiae; C419573:VPS35 protein, human
keywords: biochemical reconstitution; mass spectrometry; proteoliposome; sorting nexin