Structure of Arp2/3 complex in its activated state and in actin filament branch junctions.
The seven-subunit Arp2/3 complex choreographs the formation of branched actin networks at the leading edge of migrating cells. When activated by Wiskott-Aldrich Syndrome protein (WASp), the Arp2/3 complex initiates actin filament branches from the sides of existing filaments. Electron cryomicroscopy and three-dimensional reconstruction of Acanthamoeba castellanii and Saccharomyces cerevisiae Arp2/3 ... complexes bound to the WASp carboxy-terminal domain reveal asymmetric, oblate ellipsoids. Image analysis of actin branches indicates that the complex binds the side of the mother filament, and Arp2 and Arp3 (for actin-related protein) are the first two subunits of the daughter filament. Comparison to the actin-free, WASp-activated complexes suggests that branch initiation involves large-scale structural rearrangements within Arp2/3.
Mesh Terms:
Acanthamoeba, Actin-Related Protein 2, Actin-Related Protein 3, Actins, Animals, Cryoelectron Microscopy, Cytoskeletal Proteins, Fourier Analysis, Image Processing, Computer-Assisted, Microfilaments, Microscopy, Electron, Models, Molecular, Proteins, Saccharomyces cerevisiae, Wiskott-Aldrich Syndrome Protein
Acanthamoeba, Actin-Related Protein 2, Actin-Related Protein 3, Actins, Animals, Cryoelectron Microscopy, Cytoskeletal Proteins, Fourier Analysis, Image Processing, Computer-Assisted, Microfilaments, Microscopy, Electron, Models, Molecular, Proteins, Saccharomyces cerevisiae, Wiskott-Aldrich Syndrome Protein
Science
Date: Sep. 28, 2001
PubMed ID: 11533442
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