title: WASH drives early recycling from macropinosomes and phagosomes to maintain surface phagocytic receptors.
abstract: Macropinocytosis is an ancient mechanism that allows cells to harvest nutrients from extracellular media, which also allows immune cells to sample antigens from their surroundings. During macropinosome formation, bulk plasma membrane is internalized with all its integral proteins. It is vital for cells to salvage these proteins before degradation, but the mechanisms for sorting them are not known. Here we describe the evolutionarily conserved recruitment of the WASH (WASP and SCAR homolog) complex to both macropinosomes and phagosomes within a minute of internalization. Using Dictyostelium, we demonstrate that WASH drives protein sorting and recycling from macropinosomes and is thus essential to maintain surface receptor levels and sustain phagocytosis. WASH functionally interacts with the retromer complex at both early and late phases of macropinosome maturation, but mediates recycling via retromer-dependent and -independent pathways. WASH mutants consequently have decreased membrane levels of integrins and other surface proteins. This study reveals an important pathway enabling cells to sustain macropinocytosis without bulk degradation of plasma membrane components.
authors.affiliation: Department of Biomedical Sciences, Centre for Membrane Interactions and Dynamics, University of Sheffield, Sheffield S10 2TN, United Kingdom; Bateson Centre, University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Buckley
authors.affiliation: Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland.
authors.forename: Navin
authors.initials: N
authors.lastname: Gopaldass
authors.affiliation: Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland.
authors.forename: Cristina
authors.initials: C
authors.lastname: Bosmani
authors.affiliation: Bateson Centre, University of Sheffield, Sheffield S10 2TN, United Kingdom; Department of Infection, Immunity and Cardiovascular Sciences, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom.
authors.forename: Simon A
authors.initials: SA
authors.lastname: Johnston
authors.affiliation: Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland.
authors.forename: Thierry
authors.identifier: 0000-0002-2056-7931
authors.initials: T
authors.lastname: Soldati
authors.affiliation: Beatson Institute for Cancer Research, Glasgow G61 1BD, United Kingdom jason.king@sheffield.ac.uk r.insall@beatson.gla.ac.uk.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Insall
authors.affiliation: Department of Biomedical Sciences, Centre for Membrane Interactions and Dynamics, University of Sheffield, Sheffield S10 2TN, United Kingdom; Bateson Centre, University of Sheffield, Sheffield S10 2TN, United Kingdom; jason.king@sheffield.ac.uk r.insall@beatson.gla.ac.uk.
authors.forename: Jason S
authors.identifier: 0000-0003-0596-4506
authors.initials: JS
authors.lastname: King
mesh_terms: D002462:Cell Membrane / Q000378:metabolism*; D004023:Dictyostelium / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism; D008954:Models, Biological; D010587:Phagocytosis; D010588:Phagosomes / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D011956:Receptors, Cell Surface / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism*
chemical_list: D016023:Integrins; D011956:Receptors, Cell Surface; D033921:Vesicular Transport Proteins; D049452:Green Fluorescent Proteins; D025262:Vacuolar Proton-Translocating ATPases
keywords: Dictyostelium; WASH; macropinocytosis; phagocytosis; trafficking