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- Arp2/3 ComplexArp2/3 Complex
Cell, Volume 107, Issue 6, 14 December 2001, Pages 703-705
John A. Cooper, Martin A. Wear and Alissa M. Weaver
SummarySeveral new papers report progress on the structure and function of Arp2/3 complex. A crystal structure, a cryo-EM structure, and a reconstitution of the complex from subunits have been reported. New results also address the nucleation mechanism and the role of bound nucleotide.
Summary | Full Text | PDF (155 kb) - Interaction of Cortactin and N-WASp with Arp2/3 ComplexInteraction of Cortactin and N-WASp with Arp2/3 Complex
Current Biology, Volume 12, Issue 15, 6 August 2002, Pages 1270-1278
Alissa M. Weaver, John E. Heuser, Andrei V. Karginov, Wei-lih Lee, J.Thomas Parsons and John A. Cooper
SummaryUnder certain circumstances, cortactin and N-WASp can bind simultaneously to Arp2/3 complex, accounting for their synergy in activation of actin assembly. The interaction of cortactin NTA with Arp2/3 complex does not inhibit Arp2/3 activation by N-WASp, despite competition for a common binding site located on the Arp3 subunit. These results suggest a model in which cortactin may bridge Arp2/3 complex to actin filaments via Arp3 and N-WASp activates Arp2/3 complex by binding Arp2 and/or ARPC1/p40.
Summary | Full Text | PDF (459 kb) - Turning on the Arp2/3 Complex at Atomic ResolutionTurning on the Arp2/3 Complex at Atomic Resolution
Structure, Volume 10, Issue 2, 1 February 2002, Pages 131-135
Elizabeth L Borths and Matthew D Welch
SummaryThe recently published 2 Å X-ray crystal structure of bovine Arp2/3 complex gives us atomic scale insight into Arp2/3-mediated actin nucleation, while cryo-EM work and functional studies begin to fill in exciting mechanistic details.
Summary | Full Text | PDF (215 kb) - …more
Copyright © 2001 Cell Press. All rights reserved.
Molecular Cell, Volume 8, Issue 5, 1041-1052, 21 November 2001
doi:10.1016/S1097-2765(01)00393-8
Article
Reconstitution of Human Arp2/3 Complex Reveals Critical Roles of Individual Subunits in Complex Structure and Activity
Helene Gournier, Erin D. Goley, Hanspeter Niederstrasser, Thong Trinh and Matthew D. Welch*, 
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720 USA
Correspondence: Matthew D. Welch, (510) 643-9019 (phone), (510) 643-6791 (fax)Summary
The Arp2/3 complex is a seven-protein assembly that is critical for actin nucleation and branching in cells. Here we report the reconstitution of active human Arp2/3 complex after expression of all seven subunits in insect cells. Expression of partial complexes revealed that a heterodimer of the p34 and p20 subunits constitutes a critical structural core of the complex, whereas the remaining subunits are peripherally located. Arp3 is crucial for nucleation, consistent with it being a structural component of the nucleation site. p41, p21, and p16 contribute differently to nucleation and stimulation by ActA and WASP, whereas p34/p20 bind actin filaments and likely function in actin branching. This study reveals that the nucleating and organizing functions of Arp2/3 complex subunits are separable, indicating that these activities may be differentially regulated in cells.
