Ceramide synthase 3 (CersS3), also known as longevity assurance homologue 3, is an enzyme that is encoded in humans by the CERS3 gene.
Function
CerS3 synthesizes C24-
ceramides and ceramides with longer
acyl chains, and is found mainly in
skin and
testis.[5] Specifically, CerS3 synthesizes ceramides containing α-hydroxy (2-hydroxy)
fatty acids, which are abundant in skin tissue, where they help maintain the water permeability barrier qualities of the skin.[6] It is found in large quantities in
keratinocytes, and this increases during keratinocyte
differentiation.[7]
CerS3 (T3l) mRNA is strongly expressed in skin, and was also found in brain, lung and kidney.[9] CerS3 is mainly found in the skin and testes. CerS3 is not detectable in the
brain or the
sciatic nerve.[10] Like other
ceramide synthases, CerS3 is found in the
endoplasmic reticulum within the cell.[11]
Structure
CerS3 has a molecular mass of 46.2 kDa, 383
amino acids, and six
transmembrane domains. Like other ceramide synthases, CerS3 contains a
Hox-like domain.[11] CerS3 is the only ceramide synthase for which
splice variants have not been reported.[12]