Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), Saclay Plant Sciences, 91198 Gif-sur-Yvette, France.
1] Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), Saclay Plant Sciences, 91198 Gif-sur-Yvette, France [2] Pôle de Biologie Cellulaire, Imagif, Centre de Recherche de Gif, (FRC3115), Saclay Plant Sciences, CNRS, 91198 Gif-sur-Yvette, France.
Nat Commun. 2014 Jun 20;5:4121. doi: 10.1038/ncomms5121.
Autophagosomes are the organelles responsible for macroautophagy and arise, in yeast and animals, from the sealing of a cup-shaped double-membrane precursor, the phagophore. How the phagophore is generated and grows into a sealed autophagosome is still not clear in detail, and unknown in plants. This is due, in part, to the scarcity of structurally informative, real-time imaging data of the required protein machinery at the phagophore formation site. Here we find that in intact living Arabidopsis tissue, autophagy-related protein ATG5, which is essential for autophagosome formation, is present at the phagophore site from early, sub-resolution stages and later defines a torus-shaped structure on a flat cisternal early phagophore. Movement and expansion of this structure are accompanied by the underlying endoplasmic reticulum, suggesting tight connections between the two compartments. Detailed real-time and 3D imaging of the growing phagophore are leveraged to propose a model for autophagosome formation in plants.
自噬体是负责巨自噬的细胞器，在酵母和动物中，自噬体来源于杯状双层膜前体的封闭，即噬泡。噬泡是如何产生并生长成封闭的自噬体的，这在细节上仍然不清楚，在植物中更是未知。部分原因是在噬泡形成部位缺乏有关所需蛋白机制的结构信息丰富的实时成像数据。在这里，我们发现，在完整的活体拟南芥组织中，自噬相关蛋白 ATG5 从早期亚分辨率阶段开始就存在于噬泡部位，随后在平坦的内质网早期噬泡上定义了一个环形结构。该结构的移动和扩展伴随着下面的内质网，表明这两个隔室之间存在紧密的连接。利用对生长中的噬泡进行的详细实时和 3D 成像，提出了植物中自噬体形成的模型。
