Abstract
To identify CAP3 and CAP4, components of the CD95 (Fas/APO-1) death-inducing signaling complex, we utilized nano-electrospray tandem mass spectrometry, a recently developed technique to sequence femtomole quantities of polyacrylamide gel-separated proteins. Interestingly, CAP4 encodes a novel 55 kDa protein, designated FLICE, which has homology to both FADD and the ICE/CED-3 family of cysteine proteases. FLICE binds to the death effector domain of FADD and upon overexpression induces apoptosis that is blocked by the ICE family inhibitors, CrmA and z-VAD-fmk. CAP3 was identified as the FLICE prodomain which likely remains bound to the receptor after proteolytic activation. Taken together, this is unique biochemical evidence to link a death receptor physically to the proapoptotic proteases of the ICE/CED-3 family.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Amino Acid Sequence
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Apoptosis / physiology*
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Breast Neoplasms
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Caenorhabditis elegans Proteins
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Carcinoma
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Carrier Proteins / chemistry
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Carrier Proteins / genetics*
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Carrier Proteins / metabolism
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Caspase 8
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Caspase 9
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Caspases*
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Cysteine Endopeptidases / chemistry
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Cysteine Endopeptidases / genetics*
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Cysteine Endopeptidases / metabolism
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Cysteine Proteinase Inhibitors / pharmacology
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Fas-Associated Death Domain Protein
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Granzymes
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Helminth Proteins / chemistry
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Helminth Proteins / genetics
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Humans
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Molecular Sequence Data
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Organ Specificity
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Protein Binding
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RNA, Messenger / analysis
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Sequence Analysis
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Sequence Homology, Amino Acid
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Serine Endopeptidases
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Signal Transduction / physiology
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Tumor Cells, Cultured
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fas Receptor / physiology*
Substances
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Adaptor Proteins, Signal Transducing
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Caenorhabditis elegans Proteins
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Carrier Proteins
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Cysteine Proteinase Inhibitors
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FADD protein, human
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Fas-Associated Death Domain Protein
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Helminth Proteins
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RNA, Messenger
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fas Receptor
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GZMB protein, human
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Granzymes
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Serine Endopeptidases
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CASP8 protein, human
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CASP9 protein, human
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Caspase 8
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Caspase 9
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Caspases
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Cysteine Endopeptidases
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ced-3 protein, C elegans