Use of Sphingosine as Inhibitor of Protein Kinase C

This chapter discusses the use of sphingosine as inhibitor of protein kinase C. Protein kinase C functions as an important regulatory element of a nearly ubiquitous signal transduction system in mammalian cells. It plays critical roles in cell differentiation, tumor promotion, oncogenesis, and cell regulatory processes, such as granule secretion and hormone release. Protein kinase C exists as a family of closely related isoenzymes with differences in tissue distribution and intracellular localization. Protein kinase C isoenzymes are physiologically regulated by diacylglycerol (DAG), which is generated from membrane phospholipids in response to cell stimulation. Protein kinase C is activated pharmacologically by phorbol esters and related tumor promoters and is the predominant intracellular receptor for phorbol esters. Therefore, it has been implicated in mediating numerous biological activities attributed to phorbol esters.