Introduction to Thematic Minireview Series: Novel Bioactive Sphingolipids.

Sphingosine was named by J. L. W. Thudichum for its enigmatic properties. This descriptor has applied to sphingolipids for over a century because new enigmas continue to surface. This JBC minireview series presents articles about three novel subspecies of sphingolipids, α-galactosylceramides, 4,5-dihydroceramides, and 1-deoxysphingolipids, that have important activities but, until recently, remained undetected (or at least understudied) in the shadow of very closely related compounds. They also serve as a reminder that important metabolites still lie "off the radar screen" in reports of global and comprehensive metabolomic profiling.