Characterization of the interaction between galectin-1 and lymphocyte glycoproteins CD45 and Thy-1.
Galectin-1 is a sugar binding protein specific for beta-galactosides and not requiring metal ions for binding activity. It exists as a soluble protein which forms a noncovalent homodimer and is expressed with a broad tissue distribution. Recently, galectin-1 has been shown to play a possible role in the immune system mediating apoptosis of activated T cells with indirect evidence suggesting that galectin-1 interacts with the heavily glycosylated, transmembrane, protein phosphotyrosine phosphatase CD45. The interaction of galectin-1 with purified lymphocyte cell surface proteins was studied using surface plasmon resonance in a BIAcoretrade mark. Galectin-1 was shown to bind CD45 and Thy-1 in a carbohydrate-dependent manner. Several galectin-1 molecules could bind each CD45 molecule. The dissociation constant of dimeric galectin-1 binding to CD45 was measured at approximately 5 microM, indicating the concentration at which cross-linking of cell surface glycoproteins by galectin-1 would occur. A possible role for galectin-1 in the organization of cell surface glycoproteins is discussed.
Symons
A
A
Sir William Dunn School of Pathology, University of Oxford, UK.and.
Cooper
D N
DN
Barclay
A N
AN
D000818:Animals; D002850:Chromatography, Gel; D019281:Dimerization; D037483:Galectin 1; D006031:Glycosylation; D006388:Hemagglutinins / Q000378:metabolism*; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D008214:Lymphocytes / Q000737:chemistry*; D051381:Rats; D020349:Surface Plasmon Resonance; D018800:Thy-1 Antigens / Q000378:metabolism*
D037483:Galectin 1; D006388:Hemagglutinins; D018800:Thy-1 Antigens; D017493:Leukocyte Common Antigens