Effect of deoxycoformycin and Val-boroPro on the associated catalytic activities of lymphocyte CD26 and ecto-adenosine deaminase.
Biochem Pharmacol
; 52(11): 1757-65, 1996 Dec 13.
Article
em En
| MEDLINE
| ID: mdl-8986139
ABSTRACT
CD26 and ecto-adenosine deaminase (ADA) are found associated on the plasma membrane of T lymphocytes and each possess distinct catalytic activities. CD26 has a proteolytic activity identical to dipeptidylpeptidase IV (DPPIV; E.C. 3.4.14.5), and ecto-ADA (E.C. 3.5.4.4) degrades extracellular adenosine. The cell surface expression of CD26 and ecto-adenosine deaminase (ecto-ADA) is regulated on stimulated T lymphocytes, and ADA binding to CD26 produces a synergistic costimulatory response with T cell receptor activation. This study addresses the potential regulation by allosteric interactions of the catalytic activities of CD26 associated with ecto-ADA, which could define the mechanism of the synergism observed in T cell signaling. Cell lines genetically deficient in ADA, ligands for ADA such as adenosine, and a specific inhibitor of ADA, deoxycoformycin, were used to define the effect of ADA activity on CD26 DPPIV activity and affinity for dipeptide substrate. Conversely, a recombinant Chinese hamster ovary cell line expressing human CD26 with or without a mutation in the DPPIV catalytic domain, and the boronic acid inhibitor Val-boroPro, were used to determine the effect of DPPIV activity on ecto-ADA activity and association with CD26. These studies found no significant allosteric interaction between the catalytic activities of CD26 and ecto-ADA when associated. Therefore, signaling events in T cells involving costimulation with CD26 and ecto-ADA and the synergism observed upon ADA binding to CD26 occur independently of the catalytic activities of these cell surface molecules.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ácidos Borônicos
/
Pentostatina
/
Adenosina Desaminase
/
Dipeptidil Peptidase 4
/
Inibidores Enzimáticos
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Biochem Pharmacol
Ano de publicação:
1996
Tipo de documento:
Article