Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, Japan.
J Cell Sci. 2010 Dec 1;123(Pt 23):4107-16. doi: 10.1242/jcs.070045. Epub 2010 Nov 2.
Atg8 is a ubiquitin-like protein that is required, along with its lipidation system, for autophagy in all eukaryotic cells. The lipidated form of Atg8 is anchored on the autophagosomal membrane during autophagy. Here, we demonstrate a previously unknown role for Atg8 in vacuolar membrane dynamics. In the methylotrophic yeast Pichia pastoris, vacuoles were found to fuse to become a single spherical vacuole during adaptation from glucose- to methanol-containing medium. Atg8 is responsible for the vacuolar fusion in P. pastoris during this adaptation to methanol. Although vacuole fusion required processing of Atg8 at the C-terminus, it did not require lipidation of Atg8 for autophagy. This is the first report of the function of any Atg8 protein family member in a process other than autophagy that is independent of lipidation.
Atg8 是一种泛素样蛋白，与脂质化系统一起，在所有真核细胞中都需要进行自噬。自噬过程中，脂质化的 Atg8 形式锚定在自噬体膜上。在这里，我们证明了 Atg8 在液泡膜动力学中的一个先前未知的作用。在甲醇营养型酵母毕赤酵母中，发现在从葡萄糖到含甲醇的培养基的适应过程中，液泡融合成为单个球形液泡。Atg8 负责毕赤酵母在此适应甲醇过程中的液泡融合。尽管 Atg8 的 C 末端加工需要 Atg8 的融合，但它不需要 Atg8 的脂质化来进行自噬。这是第一个报道任何 Atg8 蛋白家族成员在自噬以外的过程中的功能的报告，该过程不依赖于脂质化。
