Global identification and characterization of both O-GlcNAcylation and phosphorylation at the murine synapse.
O-linked N-acetylglucosamine (O-GlcNAc) is a dynamic, reversible monosaccharide modifier of serine and threonine residues on intracellular protein domains. Crosstalk between O-GlcNAcylation and phosphorylation has been hypothesized. Here, we identified over 1750 and 16,500 sites of O-GlcNAcylation and phosphorylation from murine synaptosomes, respectively. In total, 135 (7%) of all O-GlcNAcylation sites were also found to be sites of phosphorylation. Although many proteins were extensively phosphorylated and minimally O-GlcNAcylated, proteins found to be extensively O-GlcNAcylated were almost always phosphorylated to a similar or greater extent, indicating the O-GlcNAcylation system is specifically targeting a subset of the proteome that is also phosphorylated. Both PTMs usually occur on disordered regions of protein structure, within which, the location of O-GlcNAcylation and phosphorylation is virtually random with respect to each other, suggesting that negative crosstalk at the structural level is not a common phenomenon. As a class, protein kinases are found to be more extensively O-GlcNAcylated than proteins in general, indicating the potential for crosstalk of phosphorylation with O-GlcNAcylation via regulation of enzymatic activity.
Department of Pharmaceutical Chemistry, UCSF, San Francisco, California 94158, USA.
Jonathan C
JC
Trinidad
David T
DT
Barkan
Brittany F
BF
Gulledge
Agnes
A
Thalhammer
Andrej
A
Sali
Ralf
R
Schoepfer
Alma L
AL
Burlingame
D000117:Acetylglucosamine / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D056148:Chromatography, Reverse-Phase; D006031:Glycosylation; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics; D010455:Peptides / Q000032:analysis* / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000032:analysis / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D013569:Synapses / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism*
D010455:Peptides; D011506:Proteins; D017351:N-Acetylglucosaminyltransferases; D000117:Acetylglucosamine