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Sphingosine kinase C

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).

Overview

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SPHK1 and SPHK2 are encoded by different genes with some redundancy of function; genetic deletion of both Sphk1 and Sphk2, but not either alone, is embryonic lethal in mice. There are splice variants of each isoform (SphK1a-c and SphK2a, b), distinguished by their N-terminal sequences. SPHK1 and SPHK2 differ in tissue distribution, sub-cellular localisation, biochemical properties and regulation. They regulate discrete pools of S1P. Receptor stimulation induces SPHK1 translocation from the cytoplasm to the plasma membrane. SPHK1 translocation is regulated by phosphorylation/dephosphorylation, specific protein:protein interactions and interaction with specific lipids at the plasma membrane. SPHK1 is a dimeric protein, as confirmed by its crystal structure which forms a positive cluster, between protomers, essential for interaction with anionic phospholipids in the plasma membrane. SPHK2 is localised to the ER or associated with mitochondria or shuttles in/out of the nucleus, regulated by phosphorylation. Intracellular targets of nuclear S1P include the catalytic subunit of telomerase (TERT) and regulators of gene expression including histone deacetylases (HDAC 1/2) and peroxisome proliferator-activated receptor gamma (PPARγ). SPHK2 phosphorylates the pro-drug FTY720 (fingolimod, which is used to treat some forms of multiple sclerosis) to a mimic of S1P and that acts as a functional antagonist of S1P1 receptors. Inhibitors of SPHK1 and SPHK2 have therapeutic potential in many diseases. Isoform-selective inhibitors are becoming available; some early inhibitors have recognised off-target effects.

Enzymes

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Targets of relevance to immunopharmacology are highlighted in blue

SPHK1 (sphingosine kinase 1) C Show summary » More detailed page go icon to follow link

SPHK2 (sphingosine kinase 2) C Show summary » More detailed page go icon to follow link

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Further reading

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References

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NC-IUPHAR subcommittee and family contributors

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How to cite this family page

Database page citation (select format):

Concise Guide to PHARMACOLOGY citation:

Alexander SPH, Fabbro D, Kelly E, Mathie AA, Peters JA, Veale EL, Armstrong JF, Faccenda E, Harding SD, Davies JA et al. (2023) The Concise Guide to PHARMACOLOGY 2023/24: Enzymes. Br J Pharmacol. 180 Suppl 2:S289-373.