Reciprocity of o-linked n-acetylglucosamine and o-phosphate on key nuclear and cytoskeletal proteins

Dynamic modification of nuclear and cvtoplasmic proteins by ()-(!lc.\Ac ap pears !o be as abundant as protein phosphorylation in virtually all eukaryotes. On several key nuclear and cvtoskeletal proteins O-CJlcNAcylation and phos phorylalion appear to be reciprocal, alternately occuping the same or nearby hydroxyl residues. O-(!lc.\Acyla1ion appears to play a key role in transcription ai initiation, appears to be invoved in nuclear pore functions, may play olic O-GlcNAc transféras3 which has fleven teiratricopeptide repeats and is remarkably conserved from I', elegans to in-iii. An O-GlcNAcase ha? also been identified and purified. Thus. O-(llcNAc ap pears to mediate the functions of a multitude of the cell's key nuclear and cytokele.tal proteins, either directly or by modulating, their phosphoryation. (Supported by NIH C'A 4'486. MH HD 13563, The Juvenile Diabetes Fdn., 1 he Mi/utani Fdn, and by Oxford Glycosciences).