3dwl
From Proteopedia
Crystal Structure of Fission Yeast Arp2/3 Complex Lacking the Arp2 Subunit
Structural highlights
Function[ARPC5_SCHPO] Functions as component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. [ARPC3_SCHPO] Functions as component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. [ARP3_SCHPO] Functions as ATP-binding component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. Seems to contact the pointed end of the daughter actin filament (By similarity). May be involved in cytokinesis. [ARPC2_SCHPO] Functions as actin-binding component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. Seems to contact the mother actin filament (By similarity). [ARPC1_SCHPO] Functions as component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. [ARPC4_SCHPO] Functions as actin-binding component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. Seems to contact the mother actin filament (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedArp2/3 (actin-related protein 2/3) complex is a seven-subunit complex that nucleates branched actin filaments in response to cellular signals. Nucleation-promoting factors such as WASp/Scar family proteins activate the complex by facilitating the activating conformational change and recruiting the first actin monomer for the daughter branch. Here we address the role of the Arp2 subunit in the function of Arp2/3 complex by isolating a version of the complex lacking Arp2 (Arp2Delta Arp2/3 complex) from fission yeast. An x-ray crystal structure of the DeltaArp2 Arp2/3 complex showed that the rest of the complex is unperturbed by the loss of Arp2. However, the Arp2Delta Arp2/3 complex was inactive in actin nucleation assays, indicating that Arp2 is essential to form a branch. A fluorescence anisotropy assay showed that Arp2 does not contribute to the affinity of the complex for Wsp1-VCA, a Schizosaccharomyces pombe nucleation-promoting factor protein. Fluorescence resonance energy transfer experiments showed that the loss of Arp2 does not prevent VCA from recruiting an actin monomer to the complex. Truncation of the N terminus of ARPC5, the smallest subunit in the complex, increased the yield of Arp2Delta Arp2/3 complex during purification but did not compromise nucleation activity of the full Arp2/3 complex. Structure and biochemical properties of fission yeast Arp2/3 complex lacking the Arp2 subunit.,Nolen BJ, Pollard TD J Biol Chem. 2008 Sep 26;283(39):26490-8. Epub 2008 Jul 18. PMID:18640983[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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