Phosphorylation and glycosylation of nucleoporins.
The nuclear pore complex mediates macromolecular transport between the nucleus and cytoplasm. Many nuclear pore components (nucleoporins) are modified by both phosphate and O-linked N-acetylglucosamine (O-GlcNAc). Among its many functions, protein phosphorylation plays essential roles in cell cycle progression. The role of O-GlcNAc addition is unknown. Here, levels of nucleoporin phosphorylation and glycosylation during cell cycle progression are examined. Whereas nuclear pore glycoproteins are phosphorylated in a cell-cycle-dependent manner, levels of O-GlcNAc remain constant. The major nucleoporin p62 can be phosphorylated in vitro by protein kinase A and glycogen synthase kinase (GSK)-3alpha but not by cyclin B/cdc2 or GSK-3beta. The consensus sites of these kinases resemble sites which can be glycosylated by O-GlcNAc transferase. These data are consistent with a model that O-GlcNAc limits nucleoporin hyperphosphorylation during M-phase and hastens the resumption of regulated nuclear transport at the completion of cell division.
Miller
M W
MW
Department of Biological Sciences, Wright State University, Dayton, Ohio, 45435-0001, USA. mwmiller@wright.edu
Caracciolo
M R
MR
Berlin
W K
WK
Hanover
J A
JA
D000117:Acetylglucosamine / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002453:Cell Cycle; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D006023:Glycoproteins / Q000378:metabolism; D006031:Glycosylation; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism*; D009865:Oocytes; D010710:Phosphates / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D014909:Wheat Germ Agglutinins / Q000378:metabolism; D014982:Xenopus laevis
D006023:Glycoproteins; D008562:Membrane Glycoproteins; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D010710:Phosphates; D020033:Protein Isoforms; D014909:Wheat Germ Agglutinins; C049312:nuclear pore protein p62; D038341:Glycogen Synthase Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D016203:CDC2 Protein Kinase; D038362:Glycogen Synthase Kinase 3; D000117:Acetylglucosamine; D005690:Galactose