Vacuolin-1 is cell-permeable inhibitor of lysosomal exocytosis and can block the Ca2+-dependent exocytosis of lysosomes and prevents the release of lysosomal content without affecting the process of resealing. Vacuolin-1 is also PIKfyve inhibitor that inhibits late-stageautophagy by impairing lysosomal maturation.
Exocytic fusion of lysosomes triggered by plasma membrane damage is proposed to be the major source of the membrane required for resealing. Vacuolin-1 is a potent and cell-permeable lysosomal exocytosis inhibitor which blocks the Ca2+-dependent exocytosis of lysosomes and prevents the release of lysosomal content without affecting the process of resealing[1]. Vacuolin-1 is also a potent inhibitor of the phosphatidylinositol phosphate kinase, PIKfyve with a Kd of 32 nM. In H4 cells expressing mCherry-GFP LC3, vacuolin-1 (3 μM; 24 hr) induced the accumulation of AcGFP- and mCherry-positive puncta, indicating that vacuolin-1 inhibits autophagy by inhibiting the degradation step of autophagosome. In HeLa cells, vacuolin-1 (3 μM; 24 hr) decreased mature cathepsin D levels and increased immature cathepsin D levels, suggesting that vacuolin-1 impairs the endosomal trafficking of de novo synthesized lysosomal enzymes, which in turn results in the suppression of the lysosomal degradation pathway. Moreover, vacuolin-1 treatment induced enlarged M6PR-positive vesicle formation (M6PR is a marker of transport between Golgi bodies and lysosomes) in HeLa cells, further suggesting that vacuolin-1 inhibits autophagy by inhibiting the maturation of lysosomes[2].
搜索
