Fokin Artem I, David Violaine, Oguievetskaia Ksenia, Derivery Emmanuel, Stone Caroline E, Cao Luyan, Rocques Nathalie, Molinie Nicolas, Henriot Véronique, Aumont-Nicaise Magali, Hinckelmann Maria-Victoria, Saudou Frédéric, Le Clainche Christophe, Carter Andrew P, Romet-Lemonne Guillaume, Gautreau Alexis M
Laboratoire de Biologie Structurale de la Cellule, CNRS, Ecole Polytechnique, IP Paris, Palaiseau, France.
Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
Sci Adv. 2021 Jan 13;7(3). doi: 10.1126/sciadv.abd5956. Print 2021 Jan.
Dendritic actin networks develop from a first actin filament through branching by the Arp2/3 complex. At the surface of endosomes, the WASH complex activates the Arp2/3 complex and interacts with the capping protein for unclear reasons. Here, we show that the WASH complex interacts with dynactin and uncaps it through its FAM21 subunit. In vitro, the uncapped Arp1/11 minifilament elongates an actin filament, which then primes the WASH-induced Arp2/3 branching reaction. In dynactin-depleted cells or in cells where the WASH complex is reconstituted with a FAM21 mutant that cannot uncap dynactin, formation of branched actin at the endosomal surface is impaired. Our results reveal the importance of the WASH complex in coordinating two complexes containing actin-related proteins.
树突状肌动蛋白网络从第一条肌动蛋白丝通过Arp2/3复合体的分支而形成。在内体表面，WASH复合体激活Arp2/3复合体，并与帽蛋白相互作用，原因不明。在这里，我们表明WASH复合体与动力蛋白相互作用，并通过其FAM21亚基将其去帽。在体外，去帽的Arp1/11微丝使肌动蛋白丝延长，然后引发WASH诱导的Arp2/3分支反应。在动力蛋白缺失的细胞中，或者在用不能使动力蛋白去帽的FAM21突变体重构WASH复合体的细胞中，内体表面分支肌动蛋白的形成受损。我们的结果揭示了WASH复合体在协调两个含有肌动蛋白相关蛋白的复合体中的重要性。
