LASS (longevity assurance homolog, also known as ceramide synthase, CerS) enzymes associated with the endoplasmic reticulum membrane catalyze the reaction of sphinganine (dihydrosphingosine) and a long-chain fatty acyl CoA such as stearyl-CoA to form a dihydroceramide and CoASH (Pewzner-Jung et al. 2006). Six human LASS genes have been identified; they differ in the identities of the fatty acyl CoAs that they use most efficiently as substrates (Lahiri and Futerman 2005; Laviad et al. 2008).
Merrill AH, Jr,