Vacuolin-1 potently and reversibly inhibits autophagosome-lysosome fusion by activating RAB5A
Autor(en): | Lu, Yingying Dong, Shichen Hao, Baixia Li, Chang Zhu, Kaiyuan Guo, Wenjing Wang, Qian Cheung, King-Ho Wong, Connie W. M. Wu, Wu-Tian Markus, Huss Yue, Jianbo |
Stichwörter: | autophagosomes; CELL; Cell Biology; DEGRADATION; ENDOSOMES; EXOCYTOSIS; GTPASE; HUNTINGTON-DISEASE; lysosomes; MATURATION; MEMBRANE; pH; PROTEIN; RAB5A; V-ATPASES; vacuolin-1 | Erscheinungsdatum: | 2014 | Herausgeber: | TAYLOR & FRANCIS INC | Journal: | AUTOPHAGY | Volumen: | 10 | Ausgabe: | 11 | Startseite: | 1895 | Seitenende: | 1905 | Zusammenfassung: | Autophagy is a catabolic lysosomal degradation process essential for cellular homeostasis and cell survival. Dysfunctional autophagy has been associated with a wide range of human diseases, e.g., cancer and neurodegenerative diseases. A large number of small molecules that modulate autophagy have been widely used to dissect this process and some of them, e.g., chloroquine (CQ), might be ultimately applied to treat a variety of autophagy-associated human diseases. Here we found that vacuolin-1 potently and reversibly inhibited the fusion between autophagosomes and lysosomes in mammalian cells, thereby inducing the accumulation of autophagosomes. Interestingly, vacuolin-1 was less toxic but at least 10-fold more potent in inhibiting autophagy compared with CQ. Vacuolin-1 treatment also blocked the fusion between endosomes and lysosomes, resulting in a defect in general endosomal-lysosomal degradation. Treatment of cells with vacuolin-1 alkalinized lysosomal pH and decreased lysosomal Ca2+ content. Besides marginally inhibiting vacuolar ATPase activity, vacuolin-1 treatment markedly activated RAB5A GTPase activity. Expression of a dominant negative mutant of RAB5A or RAB5A knockdown significantly inhibited vacuolin-1-induced autophagosome-lysosome fusion blockage, whereas expression of a constitutive active form of RAB5A suppressed autophagosome-lysosome fusion. These data suggest that vacuolin-1 activates RAB5A to block autophagosome-lysosome fusion. Vacuolin-1 and its analogs present a novel class of drug that can potently and reversibly modulate autophagy. |
ISSN: | 15548627 | DOI: | 10.4161/auto.32200 |
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