| First Author | Demon D | Year | 2009 |
| Journal | Mol Cell Proteomics | Volume | 8 |
| Issue | 12 | Pages | 2700-14 |
| PubMed ID | 19759058 | Mgi Jnum | J:180563 |
| Mgi Id | MGI:5306569 | Doi | 10.1074/mcp.M900310-MCP200 |
| Citation | Demon D, et al. (2009) Proteome-wide substrate analysis indicates substrate exclusion as a mechanism to generate caspase-7 versus caspase-3 specificity. Mol Cell Proteomics 8(12):2700-14 |
| abstractText | Caspase-3 and -7 are considered functionally redundant proteases with similar proteolytic specificities. We performed a proteome-wide screen on a mouse macrophage lysate using the N-terminal combined fractional diagonal chromatography technology and identified 46 shared, three caspase-3-specific, and six caspase-7-specific cleavage sites. Further analysis of these cleavage sites and substitution mutation experiments revealed that for certain cleavage sites a lysine at the P5 position contributes to the discrimination between caspase-7 and -3 specificity. One of the caspase-7-specific substrates, the 40 S ribosomal protein S18, was studied in detail. The RPS18-derived P6-P5' undecapeptide retained complete specificity for caspase-7. The corresponding P6-P1 hexapeptide still displayed caspase-7 preference but lost strict specificity, suggesting that P' residues are additionally required for caspase-7-specific cleavage. Analysis of truncated peptide mutants revealed that in the case of RPS18 the P4-P1 residues constitute the core cleavage site but that P6, P5, P2', and P3' residues critically contribute to caspase-7 specificity. Interestingly, specific cleavage by caspase-7 relies on excluding recognition by caspase-3 and not on increasing binding for caspase-7. |
