Probing mucin-type O-linked glycosylation in living animals.
Changes in O-linked protein glycosylation are known to correlate with disease states but are difficult to monitor in a physiological setting because of a lack of experimental tools. Here, we report a technique for rapid profiling of O-linked glycoproteins in living animals by metabolic labeling with N-azidoacetylgalactosamine (GalNAz) followed by Staudinger ligation with phosphine probes. After injection of mice with a peracetylated form of GalNAz, azide-labeled glycoproteins were observed in a variety of tissues, including liver, kidney, and heart, in serum, and on isolated splenocytes. B cell glycoproteins were robustly labeled with GalNAz but T cell glycoproteins were not, suggesting fundamental differences in glycosylation machinery or metabolism. Furthermore, GalNAz-labeled B cells could be selectively targeted with a phosphine probe by Staudinger ligation within the living animal. Metabolic labeling with GalNAz followed by Staudinger ligation provides a means for proteomic analysis of this posttranslational modification and for identifying O-linked glycoprotein fingerprints associated with disease.
Department of Chemistry, University of California, Berkeley, CA 94720, USA.
Danielle H
DH
Dube
Jennifer A
JA
Prescher
Chi N
CN
Quang
Carolyn R
CR
Bertozzi
D000116:Acetylgalactosamine / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001386:Azides / Q000737:chemistry / Q000494:pharmacology; D002460:Cell Line; D006031:Glycosylation; D006595:Hexosamines / Q000737:chemistry / Q000494:pharmacology; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D015394:Molecular Structure; D009077:Mucins / Q000737:chemistry* / Q000378:metabolism*
D001386:Azides; D006595:Hexosamines; D009077:Mucins; C405953:N-azidoacetylmannosamine; D000116:Acetylgalactosamine