Galectin-1 signaling in leukocytes requires expression of complex-type N-glycans.
Dimeric galectin-1 (dGal-1) is a homodimeric lectin with multiple proposed functions. Although dGal-1 binds to diverse glycans, it is unclear whether dGal-1 preferentially binds to specific subsets of glycans on cell surfaces to transmit signals. To explore this question, we selectively inhibited major glycan biosynthetic pathways in human HL60, Molt-4, and Jurkat cells. Inhibition of N-glycan processing blocked surface binding of dGal-1 and prevented dGal-1-induced Ca(2+) mobilization and phosphatidylserine exposure. By contrast, inhibition of O-glycan or glycosphingolipid biosynthesis did not affect dGal-1 binding or dGal-1-induced Ca(2+) mobilization and phosphatidylserine exposure. These results demonstrate that dGal-1 preferentially binds to and signals through glycoproteins containing complex-type N-glycans in at least some leukocyte subsets.
Karmakar
Sougata
S
Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.
Stowell
Sean R
SR
Cummings
Richard D
RD
McEver
Rodger P
RP
D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D019281:Dimerization; D037483:Galectin 1 / Q000378:metabolism*; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism*; D011485:Protein Binding; D015398:Signal Transduction; D013107:Sphingolipids / Q000378:metabolism
D037483:Galectin 1; D010718:Phosphatidylserines; D011134:Polysaccharides; D013107:Sphingolipids; D002118:Calcium