Ceramide synthases in mammalians, worms, and insects: emerging schemes.

The ceramide synthase (CerS) gene family comprises a group of highly conserved transmembrane proteins, which are found in all studied eukaryotes. The key feature of the CerS proteins is their role in ceramide synthase activity. Therefore, their original name 'longevity assurance gene (Lass) homologs', after the founding member, the yeast longevity assurance gene lag1, was altered to 'CerS'. All CerS have high sequence similarity in a domain called LAG1 motif and a subset of CerS proteins is predicted to contain a Homeobox (Hox) domain. These domains could be the key to the multiple roles CerS have. CerS proteins play a role in diverse biological processes such as proliferation, differentiation, apoptosis, stress response, cancer, and neurodegeneration. In this review, we focus on CerS structure and biological function with emphasis of biological functions in the widely used model systems Caenorhabditis elegans and Drosophila melanogaster. Also, we focus on the accumulating data suggesting a role for CerS in lipid homeostasis.