Catalytic and glycan-binding abilities of ppGalNAc-T2 are regulated by acetylation

ZLOCOWSKI N , SENDRA V.G, LORENZ V , VILLARREAL M.A , JORGE A, NÚÑEZ Y, BENNETT E.P, CLAUSEN H, NORES G.A , IRAZOQUI F.J

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2011 vol. 410 p. 140 - 140

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 gl