An inhibitor of O-glycosylation induces apoptosis in NIH3T3 cells and developing mouse embryonic mandibular tissues.
The family of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases (ppGaNTases) is responsible for initiating mucin-type O-linked glycosylation in higher eukaryotes. To begin to examine the biological role of O-linked glycosylation, mammalian cells were treated with a small molecule inhibitor (designated 1-68A, Ref. 15) of ppGaNTase activity. NIH3T3 cells exposed to the inhibitor were shown to undergo a significant reduction in cell surface O-glycosylation as detected by staining with jacalin and peanut agglutinin lectins after 30 min of treatment; no reduction in staining using antibodies to O-linked N-acetylglucosamine or the lectin concanavalin A was detected. Apoptosis was also observed in treated cells after 45 min of exposure, ostensibly following the O-glycosylation reduction. Overexpression of several different ppGaNTase isoforms restored cell surface O-glycosylation and rescued inhibitor-induced apoptosis. Additionally, mouse embryonic mandibular organ cultures exposed to 1-68A developed abnormally, presumably because of epithelial and mesenchymal apoptosis that followed a reduction in jacalin and peanut agglutinin staining. Our studies suggest that mucin-type O-linked glycosylation may be required for normal development and that ppGaNTases may play a role in the regulation of apoptosis.
Tian
E
E
Biological Chemistry Section, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA.
Ten Hagen
Kelly G
KG
Shum
Lillian
L
Hang
Howard C
HC
Imbert
Yoannis
Y
Young
William W
WW
Bertozzi
Carolyn R
CR
Tabak
Lawrence A
LA
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006031:Glycosylation / Q000187:drug effects; D037102:Lectins / Q000378:metabolism; D008334:Mandible / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D051379:Mice; D017350:N-Acetylgalactosaminyltransferases / Q000037:antagonists & inhibitors*; D041681:NIH 3T3 Cells; D011748:Pyrogallol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D014529:Uridine / Q000031:analogs & derivatives* / Q000494:pharmacology*
C495991:1-68A compound; D004791:Enzyme Inhibitors; D037102:Lectins; D011748:Pyrogallol; D017350:N-Acetylgalactosaminyltransferases; D014529:Uridine