2. Academic Validation
  3. CALM regulates clathrin-coated vesicle size and maturation by directly sensing and driving membrane curvature

CALM regulates clathrin-coated vesicle size and maturation by directly sensing and driving membrane curvature

  • Dev Cell. 2015 Apr 20;33(2):163-75. doi: 10.1016/j.devcel.2015.03.002.
Sharon E Miller 1,  Signe Mathiasen 2,  Nicholas A Bright 3,  Fabienne Pierre 4,  Bernard T Kelly 3,  Nikolay Kladt 5,  Astrid Schauss 5,  Christien J Merrifield 4,  Dimitrios Stamou 2,  Stefan Höning 6,  David J Owen 7
Affiliations

Affiliations

  • 1 Cambridge Institute for Medical Research and Department of Clinical Biochemistry, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK. Electronic address: sem50@cam.ac.uk.
  • 2 Bionanotechnology and Nanomedicine Laboratory, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
  • 3 Cambridge Institute for Medical Research and Department of Clinical Biochemistry, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK.
  • 4 Laboratoire d'Enzymologie et Biochimie Structurales, UPR3082 CNRS - Bat 34, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
  • 5 Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany.
  • 6 Institute of Biochemistry I and Center for Molecular Medicine Cologne, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany.
  • 7 Cambridge Institute for Medical Research and Department of Clinical Biochemistry, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK. Electronic address: djo30@cam.ac.uk.
PMID: 25898166 DOI: 10.1016/j.devcel.2015.03.002
Abstract

The size of endocytic clathrin-coated vesicles (CCVs) is remarkably uniform, suggesting that it is optimized to achieve the appropriate levels of cargo and lipid internalization. The three most abundant proteins in mammalian endocytic CCVs are clathrin and the two cargo-selecting, clathrin adaptors, CALM and AP2. Here we demonstrate that depletion of CALM causes a substantial increase in the ratio of "open" clathrin-coated pits (CCPs) to "necked"/"closed" CCVs and a doubling of CCP/CCV diameter, whereas AP2 depletion has opposite effects. Depletion of either adaptor, however, significantly inhibits endocytosis of transferrin and epidermal growth factor. The phenotypic effects of CALM depletion can be rescued by re-expression of wild-type CALM, but not with CALM that lacks a functional N-terminal, membrane-inserting, curvature-sensing/driving amphipathic helix, the existence and properties of which are demonstrated. CALM is thus a major factor in controlling CCV size and maturation and hence in determining the rates of endocytic cargo uptake.

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