3rse | pdb_00003rse
Structural and biochemical characterization of two binding sites for nucleation promoting factor WASp-VCA on Arp2/3 complex
Structural highlights
Function[ARPC4_BOVIN] 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). [ARC1B_BOVIN] 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 (By similarity). [ARPC5_BOVIN] 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 (By similarity). [ARP2_BOVIN] 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. [ARP3_BOVIN] 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. Plays a role in ciliogenesis (By similarity). [ARPC2_BOVIN] 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). [ARPC3_BOVIN] 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 (By similarity). Publication Abstract from PubMedActin-related protein (Arp) 2/3 complex mediates the formation of actin filament branches during endocytosis and at the leading edge of motile cells. The pathway of branch formation is ambiguous owing to uncertainty regarding the stoichiometry and location of VCA binding sites on Arp2/3 complex. Isothermal titration calorimetry showed that the CA motif from the C terminus of fission yeast WASP (Wsp1p) bound to fission yeast and bovine Arp2/3 complex with a stoichiometry of 2 to 1 and very different affinities for the two sites (K(d)s of 0.13 and 1.6 muM for fission yeast Arp2/3 complex). Equilibrium binding, kinetic, and cross-linking experiments showed that (i) CA at high-affinity site 1 inhibited Arp2/3 complex binding to actin filaments, (ii) low-affinity site 2 had a higher affinity for CA when Arp2/3 complex was bound to actin filaments, and (iii) Arp2/3 complex had a much higher affinity for free CA than VCA cross-linked to an actin monomer. Crystal structures showed the C terminus of CA bound to the low-affinity site 2 on Arp3 of bovine Arp2/3 complex. The C helix is likely to bind to the barbed end groove of Arp3 in a position for VCA to deliver the first actin subunit to the daughter filament. Structural and biochemical characterization of two binding sites for nucleation-promoting factor WASp-VCA on Arp2/3 complex.,Ti SC, Jurgenson CT, Nolen BJ, Pollard TD Proc Natl Acad Sci U S A. 2011 Aug 16;108(33):E463-71. Epub 2011 Jun 15. PMID:21676862[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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