Inhibition of human initiator caspase 8 and effector caspase 3 by cross-class inhibitory bovSERPINA3-1 and A3-3.
Serpins are a superfamily of structurally conserved proteins. Inhibitory serpins use a suicide substrate-like mechanism. Some are able to inhibit cysteine proteases in cross-class inhibition. Here, we demonstrate for the first time the strong inhibition of initiator and effector caspases 3 and 8 by two purified bovine SERPINA3s. SERPINA 3-1 (uniprotkb:Q9TTE1) binds tighly to human CASP3 (uniprotkb:P42574) and CASP8 (uniprotkb:Q14790) with k(ass) of 4.2x10(5) and 1.4x10(6) M(-1)s(-1), respectively. A wholly similar inhibition of human CASP3 and CASP8 by SERPINA3-3 (uniprotkb:Q3ZEJ6) was also observed with k(ass) of 1.5x10(5) and 2.7x10(6) M(-1)s(-1), respectively and form SDS-stable complexes with both caspases. By site-directed mutagenesis of bovSERPINA3-3, we identified Asp(371) as the potential P1 residue for caspases. The ability of other members of this family to inhibit trypsin and caspases was analysed and discussed.
Herrera-Mendez
Carlos H
CH
UNESS, Universidad de Guanajuato, Privada de Arteaga S/N, 38900 Salvatierra, Guanajuato, Mexico.
Becila
Samira
S
Blanchet
Xavier
X
Pelissier
Patrick
P
Delourme
Didier
D
Coulis
Gerald
G
Sentandreu
Miguel A
MA
Boudjellal
Abdelghani
A
Bremaud
Laure
L
Ouali
Ahmed
A
D000595:Amino Acid Sequence; D000818:Animals; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D061945:Caspase Inhibitors; D020134:Catalytic Domain; D002417:Cattle; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015843:Serpins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
D061945:Caspase Inhibitors; D020033:Protein Isoforms; D015843:Serpins; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8