Degradomics Reveals That Cleavage Specificity Profiles of Caspase-2 and Effector Caspases Are Alike |
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Authors: | Magdalena Wejda Francis Impens Nozomi Takahashi Petra Van Damme Kris Gevaert Peter Vandenabeele |
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Institution: | From the ‡Department for Molecular Biomedical Research, Flanders Institute for Biotechnology (VIB).;the §Department of Biomedical Molecular Biology, Ghent University, B-9052 Ghent (Zwijnaarde), Belgium.;the ¶Department of Medical Protein Research, Flanders Institute for Biotechnology (VIB), and ;the ‖Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium |
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Abstract: | Caspase-2 is considered an initiator caspase because its long prodomain contains a CARD domain that allows its recruitment and activation in several complexes by homotypic death domain-fold interactions. Because little is known about the function and specificity of caspase-2 and its physiological substrates, we compared the cleavage specificity profile of recombinant human caspase-2 with those of caspase-3 and -7 by analyzing cell lysates using N-terminal COmbined FRActional DIagonal Chromatography (COFRADIC). Substrate analysis of the 68 cleavage sites identified in 61 proteins revealed that the protease specificities of human caspases-2, -3, and -7 largely overlap, revealing the DEVD↓G consensus cleavage sequence. We confirmed that Asp563 in eukaryotic translation initiation factor 4B (eIF4B) is a cleavage site preferred by caspase-2 not only in COFRADIC setup but also upon co-expression in HEK 293T cells. These results demonstrate that activated human caspase-2 shares remarkably overlapping protease specificity with the prototype apoptotic executioner caspases-3 and -7, suggesting that caspase-2 could function as a proapoptotic caspase once released from the activating complex. |
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Keywords: | Apoptosis Caspase Protease Proteolytic Enzymes Proteomics COFRADIC Caspase-2 Degradomics |
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