N,N-dimethylsphingosine phosphorylation in human platelets.

Metabolism of sphingosine (Sph) derivatives in human platelets was examined. [3H]Sph was rapidly and heavily phosphorylated into sphingosine 1-phosphate, similarly in resting and stimulated platelets. [14C]N,N-dimethylsphingosine was stable in resting platelets, while it was converted into N,N-dimethylsphingosine 1-phosphate (DMS-1-P), although weakly, in platelets stimulated with thrombin or 12-O-tetradecanoylphorbol 13-acetate. This DMS-1-P formation was inhibited by staurosporine, a potent protein kinase inhibitor. [3H]C2-ceramide was unchanged both in resting and stimulated platelets. Our report is the first to describe production of DMS-1-P in a biological system.