Helical structures of ESCRT-III are disassembled by VPS4.
During intracellular membrane trafficking and remodeling, protein complexes known as the ESCRTs (endosomal sorting complexes required for transport) interact with membranes and are required for budding processes directed away from the cytosol, including the budding of intralumenal vesicles to form multivesicular bodies; for the budding of some enveloped viruses; and for daughter cell scission in cytokinesis. We found that the ESCRT-III proteins CHMP2A and CHMP3 (charged multivesicular body proteins 2A and 3) could assemble in vitro into helical tubular structures that expose their membrane interaction sites on the outside of the tubule, whereas the AAA-type adenosine triphosphatase VPS4 could bind on the inside of the tubule and disassemble the tubes upon adenosine triphosphate hydrolysis. CHMP2A and CHMP3 copolymerized in solution, and their membrane targeting was cooperatively enhanced on planar lipid bilayers. Such helical CHMP structures could thus assemble within the neck of an inwardly budding vesicle, catalyzing late steps in budding under the control of VPS4.
Lata
Suman
S
Unit for Virus Host Cell Interaction, UMR 5233 UJF (Université Joseph Fourier)-EMBL (European Molecular Biology Laboratory)-CNRS, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France.
Schoehn
Guy
G
Jain
Ankur
A
Pires
Ricardo
R
Piehler
Jacob
J
Gottlinger
Heinrich G
HG
Weissenhorn
Winfried
W
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000737:chemistry* / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D019281:Dimerization; D056827:Endosomal Sorting Complexes Required for Transport; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry; D008958:Models, Molecular; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D053835:Unilamellar Liposomes / Q000737:chemistry; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000378:metabolism*
D014408:Biomarkers, Tumor; C507674:CHMP2A protein, human; C498543:CHMP3 protein, human; D056827:Endosomal Sorting Complexes Required for Transport; D008051:Lipid Bilayers; D053835:Unilamellar Liposomes; D033921:Vesicular Transport Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases