INOSITOLPHOSPHOGLYCAN 2ND MESSENGERS

The mechanisms by which cellular receptors can elicit different biolog ical responses in a maturation state-dependent manner is one of the ce ntral problems in cell differentiation which remains to be resolved. T he signals generated are likely to be due to additional (as yet unknow n) transmembrane signalling pathways. In addition,the recent observati on that a single growth factor receptor can activate a whole family of different putative second messengers and that the combinatorial inter actions and stoichiometric ratios between the different messengers det ermine the resulting biological activities has opened up a whole new a rea of cell biology. It has been proposed that membrane GPI-anchors ma y function in signal transduction. We have recently confirmed the pres ence of a family of inositolphosphoglycan second messengers. Partial s tructural data suggests that these second messengers are not derived f rom known GPI membrane anchors and may thus constitute a novel class o f non-protein-conjugated GPI.