Lomonosov Moscow State University , 119991 Moscow , Russia.
Biol Open. 2012 Aug 15;1(8):802-5. doi: 10.1242/bio.20121537. Epub 2012 Jun 29.
Some nuclear envelope proteins are localised to both the nuclear envelope and the endoplasmic reticulum; therefore, it seems plausible that even small amounts of these proteins can influence the organisation of the endoplasmic reticulum. A simple method to study the possible effects of nuclear envelope proteins on endoplasmic reticulum organisation is to analyze nuclear envelope protein overexpression. Here, we demonstrate that Lap2β overexpression can induce the formation of cytoplasmic vesicular structures derived from endoplasmic reticulum membranes. Correlative light and electron microscopy demonstrated that these vesicular structures were composed of a series of closely apposed membranes that were frequently arranged in a circular fashion. Although stacked endoplasmic reticulum cisternae were highly ordered, Lap2β could readily diffuse into and out of these structures into the surrounding reticulum. It appears that low-affinity interactions between cytoplasmic domains of Lap2β can reorganise reticular endoplasmic reticulum into stacked cisternae. Although the effect of one protein may be insignificant at low concentrations, the cumulative effect of many non-specialised proteins may be significant.
一些核膜蛋白同时定位于核膜和内质网；因此，即使这些蛋白质的含量很少，也可能影响内质网的组织。研究核膜蛋白对内质网组织可能产生的影响的一种简单方法是分析核膜蛋白的过表达。在这里，我们证明 Lap2β 的过表达可以诱导源自内质网膜的细胞质囊泡结构的形成。共焦光镜和电镜显示，这些囊泡结构由一系列紧密排列的膜组成，这些膜经常以圆形方式排列。虽然堆叠的内质网腔是高度有序的，但 Lap2β 可以轻易地扩散进出这些结构，进入周围的网。似乎 Lap2β 的细胞质结构域之间的低亲和力相互作用可以将网状内质网重组为堆叠的腔。尽管在低浓度下一种蛋白质的作用可能微不足道，但许多非特异性蛋白质的累积效应可能是显著的。
