Cell Biology Laboratories, School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD.
Sci Rep. 2011;1:77. doi: 10.1038/srep00077. Epub 2011 Aug 30.
The endoplasmic reticulum (ER) represents the entry point into the secretory pathway and from here newly synthesized proteins and lipids are delivered to the Golgi. The selective cargo export from the ER is mediated by COPII-assembly at specific sites of the ER, the so-called transitional ER (tER). The peripheral membrane protein Sec16, first identified in yeast, localizes to transitional ER and plays a key role in organization of these sites. Sec16 defines the tER and is thought to act as a scaffold for the COPII coat assembly. In humans two isoforms of Sec16 are present, the larger Sec16A and the smaller Sec16B. Nevertheless, the functional differences between the two isoforms are ill-defined. Here we describe characterization of the localization and dynamics of Sec16B relative to Sec16A, provide evidence that Sec16B is likely a minor or perhaps specialized form of Sec16, and that it is not functionally redundant with Sec16A.
内质网 (ER) 代表了分泌途径的入口，从这里新合成的蛋白质和脂质被递送到高尔基体。内质网中特定部位的 COPII 组装介导了有选择性的货物输出，这些部位被称为过渡内质网 (tER)。外周膜蛋白 Sec16 最初在酵母中被鉴定出来，定位于过渡内质网，在这些部位的组织中发挥关键作用。Sec16 定义了 tER，并被认为作为 COPII 外壳组装的支架。在人类中存在两种 Sec16 同工型，较大的 Sec16A 和较小的 Sec16B。然而，这两种同工型之间的功能差异尚不清楚。在这里，我们描述了 Sec16B 相对于 Sec16A 的定位和动态的特征，提供了证据表明 Sec16B 可能是 Sec16 的一种次要或特殊形式，并且它与 Sec16A 没有功能冗余。
