Soluble ppGalNAc-T2 interacts with glycosylated RNA polymerase II

ZLOCOWSKI, NATACHA; IRAZOQUI, FERNANDO J

Mar del Plata, Buenos Aires

Congreso; XLIII Reunión Anual, Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

SAIB

O-linked N-acetylglucosamine (O-GlcNAc) glycosylation is an abundant post-translational modification of cytosolic and nuclear proteins on Ser and Thr residues. This modification often acts in a reciprocal manner to O-phosphate modification of proteins and together they can synergistically control the activity of many cellular processes. RNA polymerase II is one of nuclear proteins that change between glycosylated to phosphorilated state. C-terminal of polypeptidil GalNAc transferase 2 (ppGalNAc-T2) is a glycan-binding domain. In the present work we initiate the study of binding specificity of ppGalNAc-T2 to different glycoconjugates and cellular extract. By western blot, we saw that soluble ppGalNAc-T2 interacts with RNA pol II among others nuclear matrix components. Immunoprecipitation using anti-ppGalNAc-T2 and anti-RNA pol II antibodies also shows the interaction. ppGalNAc-T2 recognizes YSP(GlcNAc)TSPS glycopeptide that is commonly present in tandem repeats of C-terminal of RNA pol II. The ppGalNAc-T2 interaction with RNA pol II and YSP(GlcNAc)TSPS is lost when ppGalNAc-T2 is chemically acetylated; suggesting that post-translation modification can regulates ppGalNAc-T2 functions. The glycan-binding ability of ppGalNAc-T2 could be involved in gene transcription and cell proliferation through glycosylated RNA pol II interaction