Galectin-1β, a natural monomeric form of galectin-1 lacking its six amino-terminal residues promotes axonal regeneration but not cell death

We previously identified a novel N-terminally processed form of galectin-1, galectin-1(Gal-1β) whose expression was induced by ΔFosB. In the present study, the biochemical properties and biological functions of Gal-1were compared with the full-length form of galectin-1 (Gal-1α). We first purified recombinant mouse Gal-1α and β (rmGal-1α, β) to near homogeneity. The rmGal-1α, exists as a monomer under oxidized conditions and forms a dimer under reduced conditions, while the rmGal-1β exists as a monomer regardless of redox conditions. The affinity of rmGal-1β to β-lactose was approximately two-fold lower than that of rmGal-1α under reduced conditions. The viability of Jurkat cells efficiently decreased when they were exposed to rmGal-1α, however, rmGal-1β barely induced such a reduction. In contrast, both rmGal-1α and rmGal-1β exhibited an equivalent capacity to promote axonal regeneration from the dorsal root ganglion explants. Our results suggest that the biochemical properties of rmGal-1β determine its biological functions.