Galectin-1 is a stromal cell ligand of the pre-B cell receptor (BCR) implicated in synapse formation between pre-B and stromal cells and in pre-BCR triggering.
Although preB cell-receptor (pre-BCR) formation and cell-surface expression is essential for B cell development, pre-BCR generation of signal transduction remains elusive. Here, we report that recombinant pre-BCRs and the surrogate light chain bind specifically to the bone marrow stromal cell galectin-1 (GAL1), an S-type lectin. The surrogate light chain/GAL1 association is a direct protein-protein interaction (K(a) = 2 x 10(6) M(-1)), and the NH(2) extra loop of lambda-like is the major binding element. Pre-BCR binding to stromal cells depends upon GAL1 anchoring to glycosylated counter-receptors, and these complexes completely relocalize to form a synapse at the contact zone between preB and stromal cells. This immune developmental synapse is accompanied by the initiation of intracellular tyrosine kinase activity and signal transduction from the pre-BCR.
Gauthier
Laurent
L
Centre d'Immunologie de Marseille-Luminy, Centre National de la Recherche Scientifique-Institut National de la Santé et de la Recherche Médicale -Université Méditerranée, Campus de Luminy, Case 906, 13288 Marseille Cedex 09, France.
Rossi
Benjamin
B
Roux
Florence
F
Termine
Elise
E
Schiff
Claudine
C
D000818:Animals; D015153:Blotting, Western; D002448:Cell Adhesion; D002460:Cell Line; D005434:Flow Cytometry; D037483:Galectin 1 / Q000502:physiology*; D006801:Humans; D008024:Ligands; D013058:Mass Spectrometry; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D008954:Models, Biological; D054420:Pre-B Cell Receptors; D011485:Protein Binding; D011947:Receptors, Antigen, B-Cell; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D017154:Stromal Cells / Q000378:metabolism*; D020349:Surface Plasmon Resonance; D013997:Time Factors
D037483:Galectin 1; D008024:Ligands; D008562:Membrane Glycoproteins; D054420:Pre-B Cell Receptors; D011947:Receptors, Antigen, B-Cell; D011994:Recombinant Proteins