Xie Zhiping, Nair Usha, Geng Jiefei, Szefler Maciej B, Rothman Edward D, Klionsky Daniel J
Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-2216, USA.
Autophagy. 2009 Feb;5(2):217-20. doi: 10.4161/auto.5.2.7201. Epub 2009 Feb 17.
Atg8 is a ubiquitin-like protein that controls the expansion of the phagophore during autophagosome formation. It is recruited to the phagophore during the expansion stage and released upon the completion of the autophagosome. One possible model explaining the function of Atg8 is that it acts as an adaptor of a coat complex. Here, we tested the coat-adaptor model by estimating the area density of Atg8 molecules on the phagophore. We developed a computational process to simulate the random sectioning of vesicles heterogeneous in size. This method can be applied to estimate the original sizes of intracellular vesicles from sizes of their random sections obtained through transmission electron microscopy. Using this method, we found that the estimated area density of Atg8 is comparable with that of proteins that form the COPII coat.
自噬相关蛋白8（Atg8）是一种类泛素蛋白，在自噬体形成过程中控制吞噬泡的扩张。在扩张阶段，它被招募到吞噬泡上，并在自噬体形成完成后释放。一种解释Atg8功能的可能模型是，它作为一种包被复合物的衔接蛋白发挥作用。在此，我们通过估计吞噬泡上Atg8分子的面积密度来测试包被-衔接蛋白模型。我们开发了一个计算过程来模拟大小各异的囊泡的随机切片。该方法可用于根据通过透射电子显微镜获得的随机切片大小来估计细胞内囊泡的原始大小。使用该方法，我们发现Atg8的估计面积密度与形成COPII包被的蛋白质的面积密度相当。
