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 perip heral nervous system) is stimulated by the contact with axonal membran es. It is suggested that the endogenous carbohydrate-binding protein ( lectin) cerebellar soluble lectin (CSL) bound to ligands at the surfac e of axonal preparations is mitogenic for Schwann cells. Both autocrin e and axon-stimulated Schwann cell proliferations seem to be dependent on the presence of CSL and its ligands at the Schwann cell surface, a s suggested by the effects of N-glycosylation inhibitors and anti-CSL Fab fragments. These data suggest that CSL regulates Schwann cell prol iferation by clustering of a few glycoprotein ligands at the cell surf ace, consequently modulating phosphorylations.