Kuhlmann Nora, Wroblowski Sarah, Knyphausen Philipp, de Boor Susanne, Brenig Julian, Zienert Anke Y, Meyer-Teschendorf Katrin, Praefcke Gerrit J K, Nolte Hendrik, Krüger Marcus, Schacherl Magdalena, Baumann Ulrich, James Leo C, Chin Jason W, Lammers Michael
From the Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases (CECAD), Joseph-Stelzmann-Strasse 26, University of Cologne, 50931 Cologne, Germany.
the Institute for Genetics, Zülpicher Strasse 47a, University of Cologne, 50674 Cologne, Germany.
J Biol Chem. 2016 Mar 11;291(11):5484-5499. doi: 10.1074/jbc.M115.707091. Epub 2015 Dec 30.
Rho proteins are small GTP/GDP-binding proteins primarily involved in cytoskeleton regulation. Their GTP/GDP cycle is often tightly connected to a membrane/cytosol cycle regulated by the Rho guanine nucleotide dissociation inhibitor α (RhoGDIα). RhoGDIα has been regarded as a housekeeping regulator essential to control homeostasis of Rho proteins. Recent proteomic screens showed that RhoGDIα is extensively lysine-acetylated. Here, we present the first comprehensive structural and mechanistic study to show how RhoGDIα function is regulated by lysine acetylation. We discover that lysine acetylation impairs Rho protein binding and increases guanine nucleotide exchange factor-catalyzed nucleotide exchange on RhoA, these two functions being prerequisites to constitute a bona fide GDI displacement factor. RhoGDIα acetylation interferes with Rho signaling, resulting in alteration of cellular filamentous actin. Finally, we discover that RhoGDIα is endogenously acetylated in mammalian cells, and we identify CBP, p300, and pCAF as RhoGDIα-acetyltransferases and Sirt2 and HDAC6 as specific deacetylases, showing the biological significance of this post-translational modification.
Rho蛋白是一类主要参与细胞骨架调节的小GTP/GDP结合蛋白。它们的GTP/GDP循环通常与由Rho鸟嘌呤核苷酸解离抑制剂α（RhoGDIα）调节的膜/胞质溶胶循环紧密相连。RhoGDIα被认为是控制Rho蛋白体内平衡所必需的管家调节因子。最近的蛋白质组学筛选表明，RhoGDIα被广泛赖氨酸乙酰化。在此，我们首次进行了全面的结构和机制研究，以展示赖氨酸乙酰化如何调节RhoGDIα的功能。我们发现赖氨酸乙酰化会损害Rho蛋白结合，并增加鸟嘌呤核苷酸交换因子催化的RhoA上的核苷酸交换，这两个功能是构成真正的GDI置换因子的先决条件。RhoGDIα乙酰化会干扰Rho信号传导，导致细胞丝状肌动蛋白发生改变。最后，我们发现RhoGDIα在哺乳动物细胞中是内源性乙酰化的，并且我们确定CBP、p300和pCAF为RhoGDIα乙酰转移酶，Sirt2和HDAC6为特异性去乙酰化酶，这显示了这种翻译后修饰的生物学意义。
