Bifunctional role of glycosphingolipids. Modulators for transmembrane signaling and mediators for cellular interactions.

Glycosphingolipids (GSLs), or their modified catabolites, at the cell surface modulate transmembrane signal transduction by influencing protein kinases associated with growth factor receptors and protein kinase C. On the other hand, the same or different GSLs at the cell surface interact in highly specific fashion with other GSLs or with binding proteins, possibly at the surface of adjacent interacting cells or in the extracellular matrix. The GSL-GSL interaction apparently provides the basis for a specific cell recognition system independent of the fibronectin/integrin or surface lectin systems, occurring earlier during a cell recognition event.