title: Membrane protrusion powers clathrin-independent endocytosis of interleukin-2 receptor.
abstract: Endocytosis controls many functions including nutrient uptake, cell division, migration and signal transduction. A clathrin- and caveolin-independent endocytosis pathway is used by important physiological cargos, including interleukin-2 receptors (IL-2R). However, this process lacks morphological and dynamic data. Our electron microscopy (EM) and tomography studies reveal that IL-2R-pits and vesicles are initiated at the base of protrusions. We identify the WAVE complex as a specific endocytic actor. The WAVE complex interacts with IL-2R, via a WAVE-interacting receptor sequence (WIRS) present in the receptor polypeptide, and allows for receptor clustering close to membrane protrusions. In addition, using total internal reflection fluorescent microscopy (TIRF) and automated analysis we demonstrate that two timely distinct bursts of actin polymerization are required during IL-2R uptake, promoted first by the WAVE complex and then by N-WASP. Finally, our data reveal that dynamin acts as a transition controller for the recruitment of Arp2/3 activators required for IL-2R endocytosis. Altogether, our work identifies the spatio-temporal specific role of factors initiating clathrin-independent endocytosis by a unique mechanism that does not depend on the deformation of a flat membrane, but rather on that of membrane protrusions.
authors.affiliation: Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Basquin
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), FR3631, Electron Microscopy Facility, Paris, France.
authors.forename: Michaël
authors.initials: M
authors.lastname: Trichet
authors.affiliation: Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Helena
authors.initials: H
authors.lastname: Vihinen
authors.affiliation: Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Malardé
authors.affiliation: CNRS UMR3691, Paris, France Unité d'Analyse d'Images Biologiques, Institut Pasteur, Paris, France.
authors.forename: Thibault
authors.initials: T
authors.lastname: Lagache
authors.affiliation: Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France.
authors.forename: Léa
authors.initials: L
authors.lastname: Ripoll
authors.affiliation: Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Eija
authors.initials: E
authors.lastname: Jokitalo
authors.affiliation: CNRS UMR3691, Paris, France Unité d'Analyse d'Images Biologiques, Institut Pasteur, Paris, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Olivo-Marin
authors.affiliation: Laboratoire de Biochimie, Unité Mixte de Recherche 7654 Ecole Polytechnique Centre, National de la Recherche Scientifique, Palaiseau, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Gautreau
authors.affiliation: Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France nathalie.sauvonnet@pasteur.fr.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sauvonnet
mesh_terms: D000199:Actins / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D055032:Electron Microscope Tomography; D004705:Endocytosis; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D025941:Protein Interaction Mapping; D055503:Protein Multimerization; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism
chemical_list: D000199:Actins; D015375:Receptors, Interleukin-2; D051300:Wiskott-Aldrich Syndrome Protein Family
keywords: actin; cytokine receptor; dynamin; protrusion; wave regulatory complex