Artículos de revistas
Catalytic and glycan-binding abilities of ppGalNAc-T2 are regulated by acetylation
Fecha
2011-06Registro en:
Zlocowski, Natacha; Sendra, Victor German; Lorenz, Virginia; Villarreal, Marcos Ariel; Jorge, Alberto; et al.; Catalytic and glycan-binding abilities of ppGalNAc-T2 are regulated by acetylation; Academic Press Inc Elsevier Science; Biochemical and Biophysical Research Communications; 410; 1; 6-2011; 140-145
0006-291X
CONICET Digital
CONICET
Autor
Zlocowski, Natacha
Sendra, Victor German
Lorenz, Virginia
Villarreal, Marcos Ariel
Jorge, Alberto
Núñez, Yolanda
Bennett, Eric P.
Clausen, Henrik
Nores, Gustavo Alejandro
Irazoqui, Fernando Jose
Resumen
Post-translational acetylation is an important molecular regulatory mechanism affecting the biological activity of proteins. Polypeptide GalNAc transferases (ppGalNAc-Ts) are a family of enzymes that catalyze initiation of mucin-type O-glycosylation. All ppGalNAc-Ts in mammals are type II transmembrane proteins having a Golgi lumenal region that contains a catalytic domain with glycosyltransferase activity, and a C-terminal R-type (" ricin-like" ) lectin domain. We investigated the effect of acetylation on catalytic activity of glycosyltransferase, and on fine carbohydrate-binding specificity of the R-type lectin domain of ppGalNAc-T2. Acetylation effect on ppGalNAc-T2 biological activity in vitro was studied using a purified human recombinant ppGalNAc-T2. Mass spectrometric analysis of acetylated ppGalNAc-T2 revealed seven acetylated amino acids (K103, S109, K111, K363, S373, K521, and S529); the first five are located in the catalytic domain. Specific glycosyltransferase activity of ppGalNAc-T2 was reduced 95% by acetylation. The last two amino acids, K521 and S529, are located in the lectin domain, and their acetylation results in alteration of the carbohydrate-binding ability of ppGalNAc-T2. Direct binding assays showed that acetylation of ppGalNAc-T2 enhances the recognition to αGalNAc residue of MUC1αGalNAc, while competitive assays showed that acetylation modifies the fine GalNAc-binding form of the lectin domain. Taken together, these findings clearly indicate that biological activity (catalytic capacity and glycan-binding ability) of ppGalNAc-T2 is regulated by acetylation. © 2011 Elsevier Inc.