Sphingosine kinases (SphKs) are unique members of a large family of evolutionarily conserved lipid kinases that contain five conserved domains. They are expressed in humans, mice, yeast and plants, with orthologs also present in worms and flies. The two SphK isoenzymes, SphK1 and SphK2, catalyze production of the potent sphingolipid metabolite sphingosine 1-phosphate by phosphorylating sphingosine. Overexpression of SphK1 enhances proliferation of cells and growth in soft agar, promotes the G1/S transition, protects cells from apoptosis and induces tumor formation in xenografts. Downregulation of SphK1 expression usually decreases cell growth, inhibits motility, and potentiates apoptosis induced by many stress stimuli. Much less is known about the biological functions of SphK2. While mice that lack either SphK1 or SphK2 are viable, deletion of both is embryonically lethal suggesting that SphK1 and SphK2 might have overlapping functions.
Alternative names for this molecule:
Sphingosine kinase 1; SPHK; Sphk1