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Article Addendum
Autophagosome-Lysosome Fusion Depends on the pH in Acidic Compartments in CHO Cells
Akinori Kawai, Hiromi Uchiyama, Syuichi Takano, Nobuhiro Nakamura and Shoji Ohkuma
volume 3 | issue 2
March/April 2007Pages: 154 - 157
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Autophagy is the bulk degradation of cytoplasmic constituents in response to starvation and other environmental or intracellular cues. During this process, most of the cytoplasm is sequestered into autophagosomes, which then fuse with lysosomes where the degradation of the sequestered material proceeds. We investigated the relationship between autophagosome-lysosome fusion and the pH in acidic compartments by visualizing the fusion process using fluorescence in CHO cells. In this experiment, mitochondria were labeled with GFP by transfecting CHO cells with the presequence of ornithine transcarbamylase, and lysosomes were labeled with Texas Red Dextran; any fusion was identified by the colocalization of mitochondria (in autophagosomes) and lysosomes using fluorescence microscopy. When CHO cells were treated with rapamycin or starvation medium to induce autophagy, the colocalization of fluorescence was observed. Whereas when they were treated with 3-MA, an inhibitor of autophagy, the colocalization disappeared. We conclude that the colocalization reflects the fusion of autophagosomes and lysosomes. Moreover, when the CHO cells were treated with drugs that increase the pH of acidic compartments, the colocalization disappeared. This suggests that the autophagosome-lysosome fusion is inhibited by increasing pH in acidic compartments independently of V-ATPase activity in CHO cells.
Addendum to:
Quantitative Monitoring of Autophagic Degradation
Akinori Kawai, Syuichi Takano, Nobuhiro Nakamura and Shoji Ohkuma
Biochem Biophys Res Commun 2006; 351:71-7
Authors
Akinori Kawai
Kanazawa University
Hiromi Uchiyama
Kanazawa University
Syuichi Takano
Kanazawa University
Nobuhiro Nakamura
Kanazawa University
Shoji Ohkuma
Kanazawa University
We now provide open access to journal articles published online for one year or more. This article may be downloaded at the following link:
Download PDF If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.