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Mol Cell Proteomics. 2013 Oct;12(10):2921-34. doi: 10.1074/mcp.M113.028670. Epub 2013 Jun 20.

Conservation of the extended substrate specificity profiles among homologous granzymes across species.

Author information

1
Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium;

Abstract

Granzymes are structurally related serine proteases involved in cell death and immunity. To date four out of five human granzymes have assigned orthologs in mice; however for granzyme H, no murine ortholog has been suggested and its role in cytotoxicity remains controversial. Here, we demonstrate that, as is the case for granzyme C, human granzyme H is an inefficient cytotoxin that together with their similar pattern of GrB divergence and functional similarity strongly hint to their orthologous relationship. Besides analyzing the substrate specificity profile of granzyme H by substrate phage display, substrate cleavage susceptibility of human granzyme H and mouse granzyme C was assessed on a proteome-wide level. The extended specificity profiles of granzymes C and H (i.e. beyond cleavage positions P4-P4') match those previously observed for granzyme B. We demonstrate conservation of these extended specificity profiles among various granzymes as granzyme B cleavage susceptibility of an otherwise granzyme H/C specific cleavage site can simply be conferred by altering the P1-residue to aspartate, the preferred P1-residue of granzyme B. Our results thus indicate a conserved, but hitherto underappreciated specificity-determining role of extended protease-substrate contacts in steering cleavage susceptibility.

PMID:
23788529
PMCID:
PMC3790301
DOI:
10.1074/mcp.M113.028670
[Indexed for MEDLINE]
Free PMC Article

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