Functional roles of sphingosine, sphingosine 1-phosphate, and methylsphingosines: in regard to membrane sphingolipid signaling pathways.

The signaling roles of ceramide and sphingosine produced through the degrading processes of membrane sphingolipids are currently receiving hot attention in the biochemical and biomedical research fields. For these 9 years at the Biomembrane Institute in Seattle, we have studied functional roles of various sphingolipids such as ceramide, sphingosine, methylsphingosines, and sphingosine 1-phosphate in a variety of biomedical systems. In this article, first, the recent conceptual developments on sphingolipid signaling pathways is outlined. Next, our recent findings on the functional roles of sphingolipids are described focusing on (i) functional roles of sphingosine 1-phosphate in cell motility regulation and platelet activation (ii) involvement of sphingosine in cell signaling (iii) effects of methylsphingosines in cancer cell apoptosis induction and in the regulation of inflammatory processes. Based upon these findings from our studies and others, the perspective of future sphingosine research (sphingology or sphingophysiology) is briefly discussed.