美国德克萨斯大学西南医学中心Joachim Seemann小组研究发现RNA通过与GM130形成缩聚体维持高尔基体带的完整性。相关论文于2024年7月11日发表在《自然-细胞生物学》杂志上。

研究人员发现带状结构是由RNA和高尔基体基质蛋白GM130（GOLGA2）的生物分子凝聚体维持的。研究发现GM130是一种RNA膜结合蛋白，可直接将RNA和相关RNA结合蛋白招募到高尔基体膜上。细胞中RNA或GM130的急性降解会破坏带状结构。在应激条件下，RNA与GM130分离，带状结构脱节，但细胞从应激中恢复后，带状结构又会恢复。当GM130在细胞中过度表达时，会形成依赖于RNA的液态凝结物。

GM130的氨基末端含有一个固有无序结构域，该结构域与RNA结合后诱导液-液相分离。这些共凝结体足以连接纯化的高尔基体膜，将横向连接的膜堆叠重建为带状结构。这些研究共同表明，RNA是一种结构性生物聚合物，它与GM130一起维持高尔基体带状结构的完整性。

据悉，哺乳动物高尔基体是由横向连接的连续带状结构堆栈组成。在应激条件下，带状结构的完整性和功能会被破坏，但其分子机制仍不清楚。

附：英文原文

Title: RNA scaffolds the Golgi ribbon by forming condensates with GM130

Author: Zhang, Yijun, Seemann, Joachim

Issue&Volume: 2024-07-11

Abstract: The mammalian Golgi is composed of stacks that are laterally connected into a continuous ribbon-like structure. The integrity and function of the ribbon is disrupted under stress conditions, but the molecular mechanisms remain unclear. Here we show that the ribbon is maintained by biomolecular condensates of RNA and the Golgi matrix protein GM130 (GOLGA2). We identify GM130 as a membrane-bound RNA-binding protein, which directly recruits RNA and associated RNA-binding proteins to the Golgi membrane. Acute degradation of RNA or GM130 in cells disrupts the ribbon. Under stress conditions, RNA dissociates from GM130 and the ribbon is disjointed, but after the cells recover from stress the ribbon is restored. When overexpressed in cells, GM130 forms RNA-dependent liquid-like condensates. GM130 contains an intrinsically disordered domain at its amino terminus, which binds RNA to induce liquid–liquid phase separation. These co-condensates are sufficient to link purified Golgi membranes, reconstructing lateral linking of stacks into a ribbon-like structure. Together, these studies show that RNA acts as a structural biopolymer that together with GM130 maintains the integrity of the Golgi ribbon. Zhang and Seemann show that GM130 forms a complex with RNA-binding proteins. RNA binding of GM130 induces liquid–liquid phase separation and these co-condensates function to link the Golgi ribbon.

DOI: 10.1038/s41556-024-01447-2

Source: https://www.nature.com/articles/s41556-024-01447-2