The function of Ensembl gene identifier ENSG00000154227 (CERS3, ceramide synthase 3) is as follows. 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) (PubMed:17977534, PubMed:22038835, PubMed:26887952). N-acylates sphinganine and sphingosine bases to form dihydroceramides and ceramides in de novo synthesis and salvage pathways, respectively (PubMed:17977534, PubMed:22038835, PubMed:26887952). It is crucial for the synthesis of ultra-long-chain ceramides in the epidermis, to maintain epidermal lipid homeostasis and terminal differentiation (PubMed:23754960). {ECO:0000269|PubMed:17977534, ECO:0000269|PubMed:22038835, ECO:0000269|PubMed:23754960, ECO:0000269|PubMed:26887952}.