Potter M D, Seiser R M, Nicchitta C V
Dept of Cell Biology, Duke University Medical Center, Box 3709 DUMC, Durham, NC 27710, USA.
Trends Cell Biol. 2001 Mar;11(3):112-5. doi: 10.1016/s0962-8924(00)01905-x.
In current models, ribosome release from the endoplasmic reticulum (ER) is coupled to the termination of protein translation. Thus, coincident with termination, membrane-bound ribosomes dissociate into their component subunits and are released into the cytosol. Here, we review past and current data and propose that the affinity of the ribosome for the ER membrane is decreased during translation, with ribosome release occurring when a membrane-bound ribosome is engaged in the synthesis of a protein lacking a signal sequence. Our model emphasizes a role for the conformation of the large ribosomal subunit in the regulation of membrane affinity and provides a mechanism for translation-coupled ribosome release.
在当前模型中，核糖体从内质网（ER）的释放与蛋白质翻译的终止相关联。因此，与终止同时发生的是，膜结合核糖体解离成其组成亚基并释放到细胞质中。在这里，我们回顾过去和当前的数据，并提出核糖体对ER膜的亲和力在翻译过程中降低，当膜结合核糖体参与缺乏信号序列的蛋白质合成时，核糖体就会释放。我们的模型强调了大核糖体亚基的构象在调节膜亲和力中的作用，并提供了一种翻译偶联核糖体释放的机制。
