Figure 1
From: Defective Sphingosine-1-phosphate metabolism is a druggable target in Huntington’s disease

Simplified sphingolipid metabolic pathway. Ceramide (Cer) is generated through the degradation of either Sphingomyelin (SM) or Glycosphingolipids(GLS) by Sphingomyelin Phosphodiesterase (SMPD) and GlucosylCeramidase (GBA) respectively. Cer is subsequently metabolized by Ceramidase (CDse) to generate Sphingosine (Sph), which in turn produces Sphingosine-1-Phosphate (S1P) through phosphorylation by Sphingosine Kinase-1 and Sphingosine Kinase-2 (SPHK1/2). All these reactions are reversible. S1P can be catabolized into hexadecenal and phospho-ethanolamine by S1P Lyase (SGPL1).