Crystal Structure of Arp2/3 Complex

  title={Crystal Structure of Arp2/3 Complex},
  author={Robert Charles Robinson and Kirsi Turbedsky and D A Kaiser and J B Marchand and Henry N. Higgs and Senyon Choe and Thomas D. Pollard},
  pages={1679 - 1684}
We determined a crystal structure of bovine Arp2/3 complex, an assembly of seven proteins that initiates actin polymerization in eukaryotic cells, at 2.0 angstrom resolution. Actin-related protein 2 (Arp2) and Arp3 are folded like actin, with distinctive surface features. Subunits ARPC2 p34 and ARPC4 p20 in the core of the complex associate through long carboxyl-terminal α helices and have similarly folded amino-terminal α/β domains. ARPC1 p40 is a seven-blade β propeller with an insertion that… 

Conformational changes in the Arp2/3 complex leading to actin nucleation

It is shown using EM that yeast and bovine Arp2/3 complexes exist in a distribution among open, intermediate and closed conformations, and it is concluded that WASp stabilizes p35-dependent closure of the complex, holding Arp 2 and Arp3 closer together to nucleate an actin filament.

Structure and Biochemical Properties of Fission Yeast Arp2/3 Complex Lacking the Arp2 Subunit*

The role of the Arp2 subunit in the function of Arp 2/3 complex is addressed by isolating a version of the complex lacking ArP2 (Arp2Δ Arp3/3complex) from fission yeast and finding that Arp1 does not contribute to the affinity of thecomplex for Wsp1-VCA, a Schizosaccharomyces pombe nucleation-promoting factor protein.

Structure of the full-length yeast Arp7-Arp9 heterodimer.

The Arp7-Arp9 structure reveals that its dimerization interface is not altered when bound in a complex with the SWI/SNF Snf2 HSA domain and the regulatory protein Rtt102, and is unlikely to form an actin-like filament based on modelling using the structure.

Crystal structures of actin-related protein 2/3 complex with bound ATP or ADP.

Actin-related protein (Arp) 2/3 complex stimulates formation of actin filaments at the leading edge of motile cells. Nucleation of filaments depends on hydrolysis of ATP bound to Arp2. Here we report

Structure of Arp2/3 complex at a branched actin filament junction resolved by single-particle cryo-electron microscopy

This work determined a high-resolution structure of the WasP-activated Arp2/3 complex at a branch junction and used biochemical, cell biological, and molecular dynamic simulations to understand the mechanism of WASP-mediated activation.

Molecular dynamics simulations of Arp2/3 complex activation.

The structural basis of actin filament branching by the Arp2/3 complex

The actin-related protein 2/3 (Arp2/3) complex mediates the formation of branched actin filaments at the leading edge of motile cells and in the comet tails moving certain intracellular pathogens.

Arp2/3 complex is bound and activated by two WASP proteins

It is shown that activation most likely involves engagement of two distinct sites on Arp2/3 complex by two VCA molecules, each delivering an actin monomer.



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 by initiating actin filament branches from the sides of existing filaments using asymmetric, oblate ellipsoids.

Structure and function of the Arp2/3 complex.

Interaction of WASP/Scar proteins with actin and vertebrate Arp2/3 complex

It is shown that the carboxy-terminal WA domain of WASP binds to a single actin monomer with a Kd of 0.6 μM in an equilibrium with rapid exchange rates, indicating that there may be an activation step in the nucleation pathway.

The interaction of Arp2/3 complex with actin: nucleation, high affinity pointed end capping, and formation of branching networks of filaments.

It is shown that Arp2/3 complex purified from Acanthamoeba caps the pointed ends of actin filaments with high affinity and increases the critical concentration for polymerization at the pointed end from 0.6 to 1.0 microM.

The Human Arp2/3 Complex Is Composed of Evolutionarily Conserved Subunits and Is Localized to Cellular Regions of Dynamic Actin Filament Assembly

The ability of the Arp2/3 complex to induce actin polymerization and its intracellular distribution suggest that the complex promotes actin assembly in lamellipodia and may participate in lameLLipodial protrusion.

Structure, Subunit Topology, and Actin-binding Activity of the Arp2/3 Complex from Acanthamoeba

Structural and topological models for the Arp2/3 complex are proposed and it is suggested that affinity for actin filaments accounts for the localization of complex subunits to actinrich regions of Acanthamoeba.

The Arp2/3 complex nucleates actin filament branches from the sides of pre-existing filaments

Results indicate that the activated Arp2/3 complex preferentially nucleates filament branches directly on the sides of pre-existing filaments, in contrast to the dendritic nucleation model for actin-network assembly.

The Arp2/3 complex branches filament barbed ends: functional antagonism with capping proteins

It is shown that the activated Arp2/3 complex interacts with the barbed ends of filaments to initiate barbed-end branching, which quantitatively accounts for polymerization kinetics and for the length correlation of the branches offilaments observed by electron microscopy.