Department of Cellular and Molecular Medicine, George Palade Labs, University of California at San Diego, La Jolla, California 92093-0668, USA.
Nat Cell Biol. 2012 Jun 24;14(7):707-16. doi: 10.1038/ncb2523.
Although studies on endoplasmic reticulum (ER) structure and dynamics have focused on the ER tubule-forming proteins (reticulons and DP1/Yop1p) and the tubule fusion protein atlastin, nothing is known about the proteins and processes that act to counterbalance this machinery. Here we show that Lnp1p, a member of the conserved Lunapark family, plays a role in ER network formation. Lnp1p binds to the reticulons and Yop1p and resides at ER tubule junctions in both yeast and mammalian cells. In the yeast Saccharomyces cerevisiae, the interaction of Lnp1p with the reticulon protein, Rtn1p, and the localization of Lnp1p to ER junctions are regulated by Sey1p, the yeast orthologue of atlastin. We propose that Lnp1p and Sey1p act antagonistically to balance polygonal network formation. In support of this proposal, we show that the collapsed, densely reticulated ER network in lnp1 Δ cells is partially restored when the GTPase activity of Sey1p is abrogated.
虽然内质网（ER）结构和动力学的研究集中在内质网管状形成蛋白（reticulons 和 DP1/Yop1p）和管状融合蛋白 atlastin 上，但对于作用于这种机制的蛋白质和过程还一无所知。在这里，我们发现 Lnp1p，一种保守的 Lunapark 家族成员，在 ER 网络形成中发挥作用。Lnp1p 与 reticulons 和 Yop1p 结合，并存在于酵母和哺乳动物细胞的 ER 管连接处。在酵母酿酒酵母中，Lnp1p 与 reticulon 蛋白 Rtn1p 的相互作用和 Lnp1p 在 ER 连接处的定位受 Sey1p 的调节，Sey1p 是 atlastin 的酵母同源物。我们提出 Lnp1p 和 Sey1p 拮抗作用以平衡多边形网络的形成。为了支持这一观点，我们表明当 Sey1p 的 GTPase 活性被阻断时，lnp1Δ细胞中崩溃的、密集的网状 ER 网络部分得到恢复。
