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