Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854, USA.
Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854, USA
J Cell Sci. 2021 Mar 11;134(6):jcs247866. doi: 10.1242/jcs.247866.
Hippo signaling mediates influences of cytoskeletal tension on organ growth. TRIP6 and LIMD1 have each been identified as being required for tension-dependent inhibition of the Hippo pathway LATS kinases and their recruitment to adherens junctions, but the relationship between TRIP6 and LIMD1 was unknown. Using siRNA-mediated gene knockdown, we show that TRIP6 is required for LIMD1 localization to adherens junctions, whereas LIMD1 is not required for TRIP6 localization. TRIP6, but not LIMD1, is also required for the recruitment of vinculin and VASP to adherens junctions. Knockdown of TRIP6 or vinculin, but not of LIMD1, also influences the localization of myosin and F-actin. In TRIP6 knockdown cells, actin stress fibers are lost apically but increased basally, and there is a corresponding increase in the recruitment of vinculin and VASP to basal focal adhesions. Our observations identify a role for TRIP6 in organizing F-actin and maintaining tension at adherens junctions that could account for its influence on LIMD1 and LATS. They also suggest that focal adhesions and adherens junctions compete for key proteins needed to maintain attachments to contractile F-actin.
Hippo 信号通路介导细胞骨架张力对器官生长的影响。TRIP6 和 LIMD1 都被鉴定为张力依赖性抑制 Hippo 通路 LATS 激酶及其募集到黏着连接所必需的，但 TRIP6 和 LIMD1 之间的关系尚不清楚。我们使用 siRNA 介导的基因敲低，表明 TRIP6 是 LIMD1 定位于黏着连接所必需的，而 LIMD1 则不需要 TRIP6 的定位。TRIP6 但不是 LIMD1，也需要募集黏着斑蛋白和 VASP 到黏着连接。TRIP6 或黏着斑蛋白的敲低，但不是 LIMD1，也影响肌球蛋白和 F-肌动蛋白的定位。在 TRIP6 敲低的细胞中，肌动蛋白应力纤维在顶部丢失，但在底部增加，并且黏着斑蛋白和 VASP 募集到基底焦点黏附物也相应增加。我们的观察结果确定了 TRIP6 在组织 F-肌动蛋白和维持黏着连接张力中的作用，这可以解释其对 LIMD1 和 LATS 的影响。它们还表明，黏着斑和黏着连接竞争维持对收缩性 F-肌动蛋白附着所必需的关键蛋白。
