Mouse and human granzyme B have distinct tetrapeptide specificities and abilities to recruit the bid pathway.
Granzyme B is an important mediator of cytotoxic lymphocyte granule-induced death of target cells, accomplishing this through cleavage of Bid and cleavage and activation of caspases as well as direct cleavage of downstream substrates. Significant controversy exists regarding the primary pathways used by granzyme B to induce cell death, perhaps arising from the use of different protease/substrate combinations in different studies. The primary sequence of human, rat, and mouse granzymes B is well conserved, and the substrate specificity and crystal structure of the human and rat proteases are extremely similar. Although little is known about the substrate specificity of mouse granzyme B, recent studies suggest that it may differ significantly from the human protease. In these studies we show that the specificities of human and mouse granzymes B differ significantly. Human and mouse granzyme B cleave species-specific procaspase-3 more efficiently than the unmatched substrates. The distinct specificities of human and mouse granzyme B highlight a previously unappreciated requirement for Asp(192) in the acquisition of catalytic activity upon cleavage of procaspase-3 at Asp(175). Although human granzyme B efficiently cleaves human or mouse Bid, these substrates are highly resistant to cleavage by the mouse protease, strongly indicating that the Bid pathway is not a major primary mediator of the effects of mouse granzyme B. These studies provide important insights into the substrate specificity and function of the granzyme B pathway in different species and highlight that caution is essential when designing and interpreting experiments with different forms of granzyme B.
Casciola-Rosen
Livia
L
Departments of Johns Hopkins University School of Medicine, Baltimore, Maryland 21224. Electronic address: lcr@jhmi.edu.
Garcia-Calvo
Margarita
M
Department of Metabolic Disorders, Merck Research Laboratories, Rahway, New Jersey 07065.
Bull
Herbert G
HG
Department of Metabolic Disorders, Merck Research Laboratories, Rahway, New Jersey 07065.
Becker
Joseph W
JW
Department of Metabolic Disorders, Merck Research Laboratories, Rahway, New Jersey 07065.
Hines
Tonie
T
Departments of Johns Hopkins University School of Medicine, Baltimore, Maryland 21224.
Thornberry
Nancy A
NA
Department of Metabolic Disorders, Merck Research Laboratories, Rahway, New Jersey 07065.
Rosen
Antony
A
Medicine Johns Hopkins University School of Medicine, Baltimore, Maryland 21224; Departments of Johns Hopkins University School of Medicine, Baltimore, Maryland 21224; Cell Biology, and Johns Hopkins University School of Medicine, Baltimore, Maryland 21224; Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and.
D000818:Animals; D051023:BH3 Interacting Domain Death Agonist Protein / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D053148:Caspase 3 / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D016923:Cell Death / Q000276:immunology; D053804:Granzymes / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D051379:Mice; D009842:Oligopeptides / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction / Q000276:immunology; D013045:Species Specificity; D013379:Substrate Specificity; D013602:T-Lymphocytes, Cytotoxic / Q000737:chemistry / Q000201:enzymology* / Q000276:immunology
D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; C494815:Bid protein, mouse; D009842:Oligopeptides; D053804:Granzymes; C509214:Gzmb protein, mouse; C509215:Gzmb protein, rat; D053148:Caspase 3