DETAILED NOTES ON PS10

Minimal concentrations of S1P are chemotactic for osteoclast precursors, even though large concentrations inhibit their motion 79. This means that these precursors, which express both equally S1PR1 and S1PR2, are held from the vicinity in the bone by the S1P gradient: S1PR2 stops S1PR1-induced migration of these bone-resorbing cells from bone. S1PR