Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
Plant J. 2010 Nov;64(3):411-8. doi: 10.1111/j.1365-313X.2010.04337.x.
Reticulons are integral endoplasmic reticulum (ER) membrane proteins that have the ability to shape the ER into tubules. It has been hypothesized that their unusually long conserved hydrophobic regions cause reticulons to assume a wedge-like topology that induces membrane curvature. Here we provide proof of this hypothesis. When over-expressed, an Arabidopsis thaliana reticulon (RTNLB13) localized to, and induced constrictions in, cortical ER tubules. Ectopic expression of RTNLB13 was sufficient to induce ER tubulation in an Arabidopsis mutant (pah1 pah2) whose ER membrane is mostly present in a sheet-like form. By sequential shortening of the four transmembrane domains (TMDs) of RTNLB13, we show that the length of the transmembrane regions is directly correlated with the ability of RTNLB13 to induce membrane tubulation and to form low-mobility complexes within the ER membrane. We also show that full-length TMDs are necessary for the ability of RTNLB13 to reside in the ER membrane.
网蛋白是完整的内质网（ER）膜蛋白，具有将 ER 塑造成小管的能力。据推测，它们异常长的保守疏水区域使网蛋白呈现楔形拓扑结构，从而诱导膜曲率。在这里，我们提供了这个假设的证据。当过度表达时，拟南芥网蛋白（RTNLB13）定位于皮质 ER 小管并诱导其收缩。RTNLB13 的异位表达足以诱导 ER 小管化在 ER 膜主要呈片状存在的拟南芥突变体（pah1 pah2）中。通过 RTNLB13 的四个跨膜结构域（TMD）的连续缩短，我们表明跨膜区域的长度与 RTNLB13 诱导膜小管化和在 ER 膜内形成低迁移性复合物的能力直接相关。我们还表明，全长 TMD 对于 RTNLB13 驻留在 ER 膜中的能力是必要的。
