Glycosphingolipid biosynthesis is based on salvage of sphingolipids and de novo sphingolipid synthesis. Sphingoid-1-phosphate signalling molecules are synthesized through the same pathway, which starts with the transfer of a fatty acid onto serine. The diversity of products results from later dehydrogenation or hydroxylation of fatty acid moieties, as well as the usage of fatty acids of different lengths. Biosynthesis takes place in the endoplasmic reticulum lumen and the cytosol. Lipophilic products are transported to other membranes via a specialized transporter (CERT1) or the secretory pathway. Soluble sphingoid-1-phosphates are exported by multiple transporters in the plasma membrane (reviewed by Merrill 2002, Gault et al. 2010).