Granzyme B encoded by the commonly occurring human RAH allele retains pro-apoptotic activity.
A key function of human granzyme B (GrB) is to induce apoptosis of target cells in conjunction with perforin. The RAH allele is the first documented variant of the human GrB gene, occurs at a frequency of 25-30%, and encodes three amino acid substitutions (Q48R, P88A, and Y245H). It was initially reported that RAH GrB is incapable of inducing apoptosis, but here we show that it has essentially identical proteolytic and cytotoxic properties to wild type GrB. Recombinant RAH and wild type GrB cleave peptide substrates with similar kinetics, are both capable of cleaving Bid and procaspase 3, and are equally inhibited by proteinase inhibitor 9, an endogenous regulator of GrB. Furthermore, cytotoxic lymphocytes from RAH heterozygotes and homozygotes have no defect in target cell killing, and in vitro RAH GrB and wild type GrB kill cells equally well in the presence of perforin. We conclude that the RAH allele represents a neutral polymorphism in the GrB gene.
Sun
Jiuru
J
Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800, Victoria, Australia.
Bird
Catherina H
CH
Thia
Kevin Y
KY
Matthews
Antony Y
AY
Trapani
Joseph A
JA
Bird
Phillip I
PI
D000483:Alleles; D000596:Amino Acids; D000818:Animals; D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000737:chemistry; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D053804:Granzymes; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D020014:K562 Cells; D015979:Killer Cells, Lymphokine-Activated / Q000378:metabolism; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism; D051379:Mice; D010843:Pichia / Q000378:metabolism; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational; D011480:Protease Inhibitors / Q000494:pharmacology; D011994:Recombinant Proteins / Q000737:chemistry; D012697:Serine Endopeptidases / Q000096:biosynthesis* / Q000235:genetics; D013997:Time Factors
D000596:Amino Acids; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; C494815:Bid protein, mouse; D002352:Carrier Proteins; D011480:Protease Inhibitors; D011994:Recombinant Proteins; C509213:GZMB protein, human; D053804:Granzymes; C509214:Gzmb protein, mouse; D012697:Serine Endopeptidases; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases