Abstract
Cytoplasmic acidification is now recognized as a feature of apoptosis in a variety of systems. However, its relation to other events in the process of apoptosis is not yet characterized. In this work, we examined the effect of BCL-2 overexpression on acidification mediated by cycloheximide treatment or Fas ligation in Jurkat T-lymphoblasts. We find that BCL-2 overexpression attenuates cytoplasmic acidification and apoptosis detected by annexin V labeling. Acidification and phosphatidylserine externalization were found to occur concurrently. We also examined the requirement for protease activation for cytoplasmic acidification to occur and found that inhibition of interleukin-1beta converting enzyme/CED-3 family proteases (using carbobenzoxy-Val-Ala-Asp-fluoromethylketone, an inhibitor of these proteases) prevents acidification and apoptosis mediated by Fas ligation. These studies suggest that BCL-2 acts at a point upstream of acidification and that protease activation is also upstream of acidification.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Chloromethyl Ketones / pharmacology
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Apoptosis*
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Benzopyrans
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Caenorhabditis elegans Proteins
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Caspase 1
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Caspases*
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Cell Line
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Cysteine Endopeptidases / metabolism*
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Cysteine Proteinase Inhibitors / pharmacology
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Cytoplasm / metabolism
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Enzyme Activation
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Fluorescent Dyes
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Helminth Proteins / metabolism*
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Humans
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Hydrogen-Ion Concentration
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Naphthols / pharmacology
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Oligopeptides / metabolism
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Protease Inhibitors / pharmacology
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Protein-Tyrosine Kinases / biosynthesis
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Proto-Oncogene Proteins / biosynthesis*
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Proto-Oncogene Proteins c-bcl-2
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Recombinant Proteins / metabolism
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Rhodamines / pharmacology
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Transfection
Substances
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Amino Acid Chloromethyl Ketones
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Benzopyrans
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Caenorhabditis elegans Proteins
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Cysteine Proteinase Inhibitors
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Fluorescent Dyes
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Helminth Proteins
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Naphthols
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Oligopeptides
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Protease Inhibitors
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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Recombinant Proteins
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Rhodamines
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benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
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seminaphthorhodaminefluoride
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Protein-Tyrosine Kinases
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Caspases
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Cysteine Endopeptidases
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ced-3 protein, C elegans
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Caspase 1