Figure 9. Memo has an important role in cell-autonomous S1PR signaling.

S1PR1 can be activated by extracellular (red arrow) and intracellular (blue arrow) S1P. Our in vitro data demonstrate that Memo has an important role in the cell-autonomous pathway activating S1PR1 by intracellular S1P. In MEFs, absence of Memo results in a defect in cell-autonomous activation of S1PR1 during cell migration induced by PDGF. In HUVECs, knockdown of Memo results in defects in survival and junction stabilization, both of which were rescued by addition of exogenous S1P.