Single event visualization of unconventional secretion of FGF2
Single event visualization of unconventional secretion of FGF2
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DOI：
10.1083/jcb.201802008
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发表时间：
2019-02-01
影响因子：
7.8
通讯作者：
Nickel, Walter
中科院分区：
文献类型：
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作者：
Dimou, Eleni;Cosentino, Katia;Nickel, Walter
FGF2 通过非常规的分泌机制从细胞中输出。在这里，我们使用活细胞 TIRF 显微镜直接观察质膜上的单个 FGF2 膜易位事件。该过程依赖于 PI(4,5) P2 介导的内部小叶 FGF2 的募集以及硫酸乙酰肝素在外部质膜小叶捕获 FGF2。通过同时对 FGF2 膜募集和 FGF2 在细胞表面的出现进行成像，我们揭示了活细胞中 FGF2 膜易位的动力学，平均持续时间约为 200 毫秒。此外，我们直接证明了活细胞内叶中的 FGF2 寡聚体，其中 FGF2 二聚体是最突出的种类。我们提出该二聚体代表了形成膜孔的高级 FGF2 寡聚体的关键中间体，并提出了一个动力学模型，解释了膜插入的 FGF2 寡聚体在 FGF2 非常规分泌过程中作为动态易位中间体的机制。
FGF2 is exported from cells by an unconventional secretory mechanism. Here, we directly visualized individual FGF2 membrane translocation events at the plasma membrane using live cell TIRF microscopy. This process was dependent on both PI(4,5) P2-mediated recruitment of FGF2 at the inner leaflet and heparan sulfates capturing FGF2 at the outer plasma membrane leaflet. By simultaneous imaging of both FGF2 membrane recruitment and the appearance of FGF2 at the cell surface, we revealed the kinetics of FGF2 membrane translocation in living cells with an average duration of similar to 200 ms. Furthermore, we directly demonstrated FGF2 oligomers at the inner leaflet of living cells with a FGF2 dimer being the most prominent species. We propose this dimer to represent a key intermediate in the formation of higher FGF2 oligomers that form membrane pores and put forward a kinetic model explaining the mechanism by which membrane-inserted FGF2 oligomers serve as dynamic translocation intermediates during unconventional secretion of FGF2.