Jennrich Jonas, Farkas Ákos, Urlaub Henning, Schwappach Blanche, Bohnsack Katherine E
Department of Molecular Biology, University Medical Centre Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
Max Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry, Am Faßberg 11, 37077 Göttingen, Germany.
J Cell Sci. 2025 Mar 15;138(6). doi: 10.1242/jcs.263616. Epub 2025 Mar 20.
The guided-entry of tail-anchored proteins (GET) pathway is a post-translational targeting route to the endoplasmic reticulum (ER). Upon glucose withdrawal, the soluble GET proteins re-localize to dynamic cytosolic foci, here termed GET bodies. Our data reveal that the pre-targeting complex components, Sgt2 and the Get4-Get5 heterodimer, and the Get3 ATPase play important roles in the assembly of these structures in Saccharomyces cerevisiae. More specifically, the TPR region of Sgt2 is required as a GET body scaffold. Systematic compositional analyses of GET bodies reveal their chaperone-rich nature and the presence of numerous proteins involved in metabolic processes. Temporal analyses of GET body assembly demonstrate the sequential recruitment of different chaperones, and we discover the requirement of Sis1 and Sti1 for maintaining the dynamic properties of these structures. In vivo, NADH derived from the oxidation of ethanol to acetaldehyde can induce GET body disassembly in a reaction depending on the alcohol dehydrogenase Adh2 and in vitro, addition of NADH resolves GET bodies. This suggests a mechanistic basis for their formation and disassembly in response to the metabolic shift caused by glucose withdrawal and re-addition.
尾锚定蛋白(GET)导入途径是内质网(ER)的一种翻译后靶向途径。在葡萄糖缺乏时,可溶性GET蛋白重新定位到动态的胞质焦点,此处称为GET小体。我们的数据表明,靶向前复合体组分Sgt2和Get4-Get5异二聚体以及Get3 ATP酶在酿酒酵母中这些结构的组装中起重要作用。更具体地说,Sgt2的TPR区域是GET小体支架所必需的。对GET小体的系统组成分析揭示了它们富含分子伴侣的性质以及存在许多参与代谢过程的蛋白质。对GET小体组装的时间分析表明不同分子伴侣的顺序募集,并且我们发现Sis1和Sti1对于维持这些结构的动态特性是必需的。在体内,乙醇氧化为乙醛产生的NADH可在依赖于醇脱氢酶Adh2的反应中诱导GET小体解体,并且在体外,添加NADH可使GET小体溶解。这表明了它们响应葡萄糖缺乏和重新添加引起的代谢转变而形成和解体的机制基础。