RPEL-family rhoGAPs link Rac/Cdc42 GTP loading to G-actin availability
RPEL-family rhoGAPs link Rac/Cdc42 GTP loading to G-actin availability
复制标题
DOI：
10.1038/s41556-019-0337-y
复制
发表时间：
2019-07-01
影响因子：
21.3
通讯作者：
Treisman, Richard
中科院分区：
文献类型：
--
作者：
Diring, Jessica;Mouilleron, Stephane;Treisman, Richard
RPEL蛋白，其中包含G-肌动蛋白结合RPEL基序，协调细胞骨架过程与肌动蛋白动力学。我们表明，ArhGAP 12和ArhGAP 32家族GTP酶激活蛋白（GAP）是RPEL蛋白。我们确定的ArhGAP 12/G-肌动蛋白复合物的结构，并显示G-肌动蛋白接触的RPEL基序和GAP结构域序列。G-肌动蛋白抑制ArhGAP 12 GAP活性，这需要在结构中鉴定的G-肌动蛋白接触。在B16黑色素瘤细胞中，ArhGAP 12抑制基础Rac和Cdc 42活性、F-肌动蛋白组装、侵袭伪足形成和实验性转移。在这种情况下，G-肌动蛋白结合缺陷的ArhGAP 12突变体在HGF刺激后表现出更有效的Rac GTP负载下调，并增强了对Rac依赖性过程（包括侵袭伪足形成）的抑制。通过用肌动蛋白结合药物latrunculin B或细胞松弛素D处理，G-肌动蛋白/ArhGAP 12相互作用的增强或破坏对Rac GTP负载具有相应的影响。因此，G-肌动蛋白与RPEL-家族rhoGAP的相互作用提供了将Rac活性与肌动蛋白动力学耦合的负反馈回路。
RPEL proteins, which contain the G-actin-binding RPEL motif, coordinate cytoskeletal processes with actin dynamics. We show that the ArhGAP12- and ArhGAP32-family GTPase-activating proteins (GAPs) are RPEL proteins. We determine the structure of the ArhGAP12/G-actin complex, and show that G-actin contacts the RPEL motif and GAP domain sequences. G-actin inhibits ArhGAP12 GAP activity, and this requires the G-actin contacts identified in the structure. In B16 melanoma cells, ArhGAP12 suppresses basal Rac and Cdc42 activity, F-actin assembly, invadopodia formation and experimental metastasis. In this setting, ArhGAP12 mutants defective for G-actin binding exhibit more effective downregulation of Rac GTP loading following HGF stimulation and enhanced inhibition of Rac-dependent processes, including invadopodia formation. Potentiation or disruption of the G-actin/ArhGAP12 interaction, by treatment with the actin-binding drugs latrunculin B or cytochalasin D, has corresponding effects on Rac GTP loading. The interaction of G-actin with RPEL-family rhoGAPs thus provides a negative feedback loop that couples Rac activity to actin dynamics.