Lunapark stabilizes nascent three-way junctions in the endoplasmic reticulum
Lunapark stabilizes nascent three-way junctions in the endoplasmic reticulum
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DOI：
10.1073/pnas.1423026112
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发表时间：
2015-01-13
影响因子：
11.1
通讯作者：
Novick, Peter J.
中科院分区：
文献类型：
--
作者：
Chen, Shuliang;Desai, Tanvi;Novick, Peter J.
内质网（ER）是由一个多边形的网状结构组成，网状结构中有由三向连接点连接的片层和小管。该网络通过竞争过程进行持续的重塑：小管的分支和融合形成新的三通接头和新的多边形，接头滑动和环闭合导致多边形丢失。然而，很少有人知道的机械所需的产生和维持路口。我们以前报道，酵母LNP 1定位于ER连接，LNP 1的损失导致崩溃，密集的网状ER网络。在哺乳动物细胞中，只有大约一半的连接含有Lnp1。在这里，我们使用活细胞成像显示，哺乳动物Lnp1（mLnp1）影响ER连接的流动性，因此网络动态。有mLnp 1的三向连接比没有mLnp 1的连接移动的少。获得mLnp1的新形成的连接在ER网络内保持稳定，而未能获得mLnp1的新生连接经历快速的环闭合。这些发现意味着mLnp1在稳定新生的三向ER连接中起着关键作用。
The endoplasmic reticulum (ER) consists of a polygonal network of sheets and tubules interconnected by three-way junctions. This network undergoes continual remodeling through competing processes: the branching and fusion of tubules forms new three-way junctions and new polygons, and junction sliding and ring closure leads to polygon loss. However, little is known about the machinery required to generate and maintain junctions. We previously reported that yeast Lnp1 localizes to ER junctions, and that loss of Lnp1 leads to a collapsed, densely reticulated ER network. In mammalian cells, only approximately half the junctions contain Lnp1. Here we use live cell imaging to show that mammalian Lnp1 (mLnp1) affects ER junction mobility and hence network dynamics. Three-way junctions with mLnp1 are less mobile than junctions without mLnp1. Newly formed junctions that acquire mLnp1 remain stable within the ER network, whereas nascent junctions that fail to acquire mLnp1 undergo rapid ring closure. These findings imply that mLnp1 plays a key role in stabilizing nascent three-way ER junctions.