Ceramide synthase that catalyzes the transfer of the acyl chain from acyl-CoA to a sphingoid base, with high selectivity toward very- and ultra-long-chain fatty acyl-CoA (chain length greater than C22) ( ). N-acylates sphinganine and sphingosine bases to form dihydroceramides and ceramides in de novo synthesis and salvage pathways, respectively ( ). It is crucial for the synthesis of ultra-long-chain ceramides in the epidermis, to maintain epidermal lipid homeostasis and terminal differentiation .
Subcellular locations: Endoplasmic reticulum membrane
Expressed in the epidermis, where it localizes at the interface between the stratum granulosum and the stratum corneum (at protein level).