title: Identification of molecular heterogeneity in SNX27-retromer-mediated endosome-to-plasma-membrane recycling.
abstract: Retromer is a protein assembly that orchestrates the sorting of transmembrane cargo proteins into endosome-to-Golgi and endosome-to-plasma-membrane transport pathways. Here, we have employed quantitative proteomics to define the interactome of human VPS35, the core retromer component. This has identified a number of new interacting proteins, including ankyrin-repeat domain 50 (ANKRD50), seriologically defined colon cancer antigen 3 (SDCCAG3) and VPS9-ankyrin-repeat protein (VARP, also known as ANKRD27). Depletion of these proteins resulted in trafficking defects of retromer-dependent cargo, but differential and cargo-specific effects suggested a surprising degree of functional heterogeneity in retromer-mediated endosome-to-plasma-membrane sorting. Extending this, suppression of the retromer-associated WASH complex did not uniformly affect retromer cargo, thereby confirming cargo-specific functions for retromer-interacting proteins. Further analysis of the retromer-VARP interaction identified a role for retromer in endosome-to-melanosome transport. Suppression of VPS35 led to mistrafficking of the melanogenic enzymes, tyrosinase and tryrosine-related protein 1 (Tyrp1), establishing that retromer acts in concert with VARP in this trafficking pathway. Overall, these data reveal hidden complexities in retromer-mediated sorting and open up new directions in our molecular understanding of this essential sorting complex.
authors.affiliation: The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: McGough
authors.affiliation: The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: Florian
authors.initials: F
authors.lastname: Steinberg
authors.affiliation: The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Gallon
authors.affiliation: Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Yatsu
authors.affiliation: Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Ohbayashi
authors.affiliation: Proteomics Facility, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: Kate J
authors.initials: KJ
authors.lastname: Heesom
authors.affiliation: Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Fukuda
authors.affiliation: The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK Pete.Cullen@bristol.ac.uk.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Cullen
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D021381:Protein Transport; D058305:Sorting Nexins / Q000378:metabolism*; D014162:Transfection; D014168:Transferrin / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism
chemical_list: C522885:SNX27 protein, human; D058305:Sorting Nexins; D014168:Transferrin; C419573:VPS35 protein, human; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins
keywords: Retromer; SNX27; Sorting nexin; VARP; VPS35