Ubiquitin-protein conjugates accumulate in the lysosomal system of fibroblasts treated with cysteine proteinase inhibitors
Keyword(s):
Mouse fibroblasts (3T3-L1 cells) accumulate detergent- and salt-insoluble aggregates of proteins conjugated to ubiquitin when incubated in the presence of inhibitors of lysosomal cysteine cathepsins, including E-64. These ubiquitin-protein conjugates co-fractionate with lysosomes on density gradients and are found in multivesicular dense bodies which by electron microscopy appear to be engaged in microautophagy. Both E-64 and ammonium chloride increase the intracellular concentration of free ubiquitin, but only E-64 leads to the formation of insoluble lysosomal ubiquitin-protein conjugates. The results are discussed in relation to the possible intracellular roles of ubiquitin conjugation.
2018 ◽
Vol 12
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pp. 601-612
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1988 ◽
Vol 48
(sup191)
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pp. 21-31
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Keyword(s):
1992 ◽
Vol 3
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pp. 307-332
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1994 ◽
Vol 116
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pp. 399-405
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2003 ◽
Vol 136
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pp. 309-316
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