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

AUTOR(ES)

Gauthier, Laurent

FONTE

The National Academy of Sciences

RESUMO

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 (Ka = 2 × 106 M−1), and the NH2 extra loop of λ-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.

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