An endogenous lectin and its glycoprotein ligands are triggering basal and axon-induced Schwann cell proliferation.

The proliferation of Schwann cells (the myelinating cells of the peripheral nervous system) is stimulated by the contact with axonal membranes. It is suggested that the endogenous carbohydrate-binding protein (lectin) cerebellar soluble lectin (CSL) bound to ligands at the surface of axonal preparations is mitogenic for Schwann cells. Both autocrine and axon-stimulated Schwann cell proliferations seem to be dependent on the presence of CSL and its ligands at the Schwann cell surface, as suggested by the effects of N-glycosylation inhibitors and anti-CSL Fab fragments. These data suggest that CSL regulates Schwann cell proliferation by clustering of a few glycoprotein ligands at the cell surface, consequently modulating phosphorylations.