Lipid transporter that specifically mediates export of sphingosine-1-phosphate (sphing-4-enine 1-phosphate, S1P) and sphinganine-1-phosphate. sphing-4-enine 1-phosphate(in) = sphing-4-enine 1-phosphate(out) sphinganine 1-phosphate(in) = sphinganine 1-phosphate(out) Belongs to the major facilitator superfamily. Spinster (TC 2.A.1.49) family.