N-ACETYLGLUCOSAMINE-DEPENDENT NUCLEAR IMPORT OF NEOGLYCOPROTEINS

Nuclear proteins bearing O-linked N-acetylglucosaminyl residues are in volved in nuclear transport and in transcriptional processes, However, the role of glycosylation remains to be determined, It was proposed t hat glycosylation could be involved in macromolecular complex formatio n or in nuclear targeting, In the present study, we show that, in digi tonin-permeabilized cells, BSA substituted with beta-di-N-acetylchitob ioside (GlcNAc beta 4GlcNAc) is transported from the cytosol to the nu cleus in a sugar dependent manner. The process is time and ATP depende nt, Under the conditions used, the nuclear import of beta-di-N-acetyl- chitobios BSA, as it has also been previously shown for the nuclear im port of alpha-glucosyl BSA (Duverger et al., J, Cell Sci., 108, 1325-1 332, 1995) does not require the addition of a cytosolic extract, while the nuclear import of peptidic-NLS substituted BSA does require such an addition, These results suggest that GlcNAc can act as a nuclear lo calization signal.