TY - JOUR
T1 - Structural Basis of Arp2/3 Complex Inhibition by GMF, Coronin, and Arpin
AU - Sokolova, Olga S.
AU - Chemeris, Angelina
AU - Guo, Siyang
AU - Alioto, Salvatore L.
AU - Gandhi, Meghal
AU - Padrick, Shae
AU - Pechnikova, Evgeniya
AU - David, Violaine
AU - Gautreau, Alexis
AU - Goode, Bruce L.
N1 - Funding Information:
Electron microscopy was performed at the user facilities center of the Biology department of M.V. Lomonosov Moscow University. O.S.S. and members of her lab were supported by a grant from the Russian Science Foundation (14-14-00234). S.P. was supported by grants to Michael K. Rosen from the HHMI, the NIH (R01-GM56322), and the Welch Foundation (I?1544). B.L.G. and members of his lab were supported by a grant from the NIH (GM063691).
PY - 2017/1/20
Y1 - 2017/1/20
N2 - The evolutionarily conserved Arp2/3 complex plays a central role in nucleating the branched actin filament arrays that drive cell migration, endocytosis, and other processes. To better understand Arp2/3 complex regulation, we used single-particle electron microscopy to compare the structures of Arp2/3 complex bound to three different inhibitory ligands: glia maturation factor (GMF), Coronin, and Arpin. Although the three inhibitors have distinct binding sites on Arp2/3 complex, they each induced an “open” nucleation-inactive conformation. Coronin promoted a standard (previously described) open conformation of Arp2/3 complex, with the N-terminal β-propeller domain of Coronin positioned near the p35/ARPC2 subunit of Arp2/3 complex. GMF induced two distinct open conformations of Arp2/3 complex, which correlated with the two suggested binding sites for GMF. Furthermore, GMF synergized with Coronin in inhibiting actin nucleation by Arp2/3 complex. Arpin, which uses VCA-related acidic (A) motifs to interact with the Arp2/3 complex, induced the standard open conformation, and two new masses appeared at positions near Arp2 and Arp3. Furthermore, Arpin showed additive inhibitory effects on Arp2/3 complex with Coronin and GMF. Together, these data suggest that Arp2/3 complex conformation is highly polymorphic and that its activities can be controlled combinatorially by different inhibitory ligands.
AB - The evolutionarily conserved Arp2/3 complex plays a central role in nucleating the branched actin filament arrays that drive cell migration, endocytosis, and other processes. To better understand Arp2/3 complex regulation, we used single-particle electron microscopy to compare the structures of Arp2/3 complex bound to three different inhibitory ligands: glia maturation factor (GMF), Coronin, and Arpin. Although the three inhibitors have distinct binding sites on Arp2/3 complex, they each induced an “open” nucleation-inactive conformation. Coronin promoted a standard (previously described) open conformation of Arp2/3 complex, with the N-terminal β-propeller domain of Coronin positioned near the p35/ARPC2 subunit of Arp2/3 complex. GMF induced two distinct open conformations of Arp2/3 complex, which correlated with the two suggested binding sites for GMF. Furthermore, GMF synergized with Coronin in inhibiting actin nucleation by Arp2/3 complex. Arpin, which uses VCA-related acidic (A) motifs to interact with the Arp2/3 complex, induced the standard open conformation, and two new masses appeared at positions near Arp2 and Arp3. Furthermore, Arpin showed additive inhibitory effects on Arp2/3 complex with Coronin and GMF. Together, these data suggest that Arp2/3 complex conformation is highly polymorphic and that its activities can be controlled combinatorially by different inhibitory ligands.
KW - actin nucleation
KW - conformation
KW - single-particle EM
KW - yeast
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U2 - 10.1016/j.jmb.2016.11.030
DO - 10.1016/j.jmb.2016.11.030
M3 - Article
C2 - 27939292
AN - SCOPUS:85008230376
VL - 429
SP - 237
EP - 248
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 2
ER -