Sphingosine 1-phosphate (S1P) is a pleiotropic mediator involved in a variety of cellular functions. It is a product of cell membrane sphingolipid catabolism as it is generated from sphingosine intracellularly by sphingosine kinases 1 and 2 (SphK1 and SphK2), and it is exported from cells by spinster homolog 2 (Spns2) or major facilitator superfamily 2b (Mfsd2b).