Three-dimensional reconstruction of dynamin in the constricted state.

Nat Cell Biol

Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Building 8, Room 419, MSC 0851, 8 Center Drive, National Institutes of Health, Bethesda, Maryland 20892, USA.

Published: October 2001

Members of the dynamin family of GTPases have unique structural properties that might reveal a general mechanochemical basis for membrane constriction. Receptor-mediated endocytosis, caveolae internalization and certain trafficking events in the Golgi all require dynamin for vesiculation. The dynamin-related protein Drp1 (Dlp1) has been implicated in mitochondria fission and a plant dynamin-like protein phragmoplastin is involved in the vesicular events leading to cell wall formation. A common theme among these proteins is their ability to self-assemble into spirals and their localization to areas of membrane fission. Here we present the first three-dimensional structure of dynamin at a resolution of approximately 20 A, determined from cryo-electron micrographs of tubular crystals in the constricted state. The map reveals a T-shaped dimer consisting of three prominent densities: leg, stalk and head. The structure suggests that the dense stalk and head regions rearrange when GTP is added, a rearrangement that generates a force on the underlying lipid bilayer and thereby leads to membrane constriction. These results indicate that dynamin is a force-generating 'contrictase'.

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http://dx.doi.org/10.1038/ncb1001-922DOI Listing

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