Activation of transglutaminase in mu-calpain null erythrocytes.
Biochem Biophys Res Commun
; 307(2): 327-31, 2003 Jul 25.
Article
em En
| MEDLINE
| ID: mdl-12859959
ABSTRACT
Intracellular transglutaminases (protein-glutamine amine gamma-glutamyltransferase, EC 2.3.2.13) are calcium-dependent thiol enzymes that catalyze the covalent cross-linking of proteins, including those in the erythrocyte membrane. Several studies suggest that the activation of some transglutaminases is positively regulated by the calcium-dependent cysteine protease, mu-calpain. Using mu-calpain null (Capn1(-/-)) mouse erythrocytes, we demonstrate that the activation of soluble as well as membrane-bound forms of transglutaminase (TG2) in mouse erythrocytes was independent of mu-calpain. Also, the absence of mu-calpain or any detectable cysteine protease did not affect the transglutaminase activity in the erythrocyte lysate. Our studies also identify physiological substrates of mu-calpain in the erythrocyte membrane and show that their cleavage has no discernible effect on the transglutaminase mediated cross-linking of membrane proteins. Taken together, these data suggest the existence of a calpain-independent mechanism for the activation of transglutaminase 2 by calcium ions in the mouse erythrocytes and presumably also in non-erythroid cells.
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Base de dados:
MEDLINE
Assunto principal:
Calpaína
/
Transglutaminases
/
Proteínas de Ligação ao GTP
/
Eritrócitos
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article