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. 2019 Apr 3;132(7):jcs224063. doi: 10.1242/jcs.224063.
Adherens junctions provide attachments between neighboring epithelial cells and a physical link to the cytoskeleton, which enables them to sense and transmit forces and to initiate biomechanical signaling. Examination of the Ajuba LIM protein Jub in embryos revealed that it is recruited to adherens junctions in tissues experiencing high levels of myosin activity, and that the pattern of Jub recruitment varies depending upon how tension is organized. In cells with high junctional myosin, Jub is recruited to puncta near intercellular vertices, which are distinct from Ena-containing puncta, but can overlap Vinc-containing puncta. We identify roles for Jub in modulating tension and cellular organization, which are shared with the cytohesin Step, and the cytohesin adapter Sstn, and show that Jub and Sstn together recruit Step to adherens junctions under tension. Our observations establish Jub as a reporter of tension experienced at adherens junctions, and identify distinct types of tension-dependent and tension-independent junctional complexes. They also identify a role for Jub in mediating a feedback loop that modulates the distribution of tension and cellular organization in epithelia.
黏着连接为相邻上皮细胞提供附着，并与细胞骨架建立物理连接，使它们能够感知和传递力，并启动生物力学信号。在 胚胎中对 Ajuba LIM 蛋白 Jub 的研究表明，它被招募到肌球蛋白活性水平高的黏着连接部位，而且 Jub 的募集模式取决于张力的组织方式。在具有高连接肌球蛋白的细胞中，Jub 被招募到细胞间顶点附近的点状结构，这些点状结构与含有 Ena 的点状结构不同，但可以与含有 Vinc 的点状结构重叠。我们确定了 Jub 在调节张力和细胞组织方面的作用，这与细胞丝氨酸苏氨酸激酶 Step 和细胞丝氨酸苏氨酸激酶适配器 Sstn 共享，并且表明在张力下，Jub 和 Sstn 一起将 Step 招募到黏着连接。我们的观察结果确立了 Jub 作为黏着连接处所经历张力的报告蛋白，并确定了不同类型的依赖张力和不依赖张力的连接复合物。它们还确定了 Jub 在介导反馈回路中的作用，该反馈回路调节上皮细胞中张力的分布和细胞组织。
