Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America.
PLoS One. 2022 Aug 15;17(8):e0269208. doi: 10.1371/journal.pone.0269208. eCollection 2022.
The Ajuba LIM protein Jub mediates regulation of Hippo signaling by cytoskeletal tension through interaction with the kinase Warts and participates in feedback regulation of junctional tension through regulation of the cytohesin Steppke. To investigate how Jub interacts with and regulates its distinct partners, we investigated the ability of Jub proteins missing different combinations of its three LIM domains to rescue jub phenotypes and to interact with α-catenin, Warts and Steppke. Multiple regions of Jub contribute to its ability to bind α-catenin and to localize to adherens junctions in Drosophila wing imaginal discs. Co-immunoprecipitation experiments in cultured cells identified a specific requirement for LIM2 for binding to Warts. However, in vivo, both LIM1 and LIM2, but not LIM3, were required for regulation of wing growth, Yorkie activity, and Warts localization. Conversely, LIM2 and LIM3, but not LIM1, were required for regulation of cell shape and Steppke localization in vivo, and for maximal Steppke binding in co-immunoprecipitation experiments. These observations identify distinct functions for the different LIM domains of Jub.
Ajuba LIM 蛋白 Jub 通过与激酶 Warts 的相互作用介导细胞骨架张力对 Hippo 信号的调节，并通过调节细胞丝氨酸 Steppke 参与连接张力的反馈调节。为了研究 Jub 如何与其不同的伴侣相互作用和调节，我们研究了缺失其三个 LIM 结构域不同组合的 Jub 蛋白是否能够挽救 jub 表型，并与α-连环蛋白、Warts 和 Steppke 相互作用。Jub 蛋白的多个区域有助于其与α-连环蛋白结合，并在果蝇翅 imaginal 盘的黏着连接点定位。在培养细胞中的共免疫沉淀实验鉴定出 LIM2 对于与 Warts 结合的特定要求。然而，在体内，LIM1 和 LIM2，但不是 LIM3，都需要调节翅膀生长、Yorkie 活性和 Warts 定位。相反，LIM2 和 LIM3，但不是 LIM1，在体内调节细胞形状和 Steppke 定位，以及在共免疫沉淀实验中最大程度地结合 Steppke 是必需的。这些观察结果确定了 Jub 的不同 LIM 结构域的不同功能。
