Figures & data
Figure 1 Structures of AcylCer. Abbreviation for Cer structures are according to Robson et al. and Motta et al. N, A and EO indicate amide-linked FA species: N, non-OH FA; and EO, ω-O-esterified FA. A, S, P and H indicate sphingoid base structures: S, sphingosine (or sphingenine); P, 4-hydroxysphinganine (or phytosphingosine); and H, 6-hydroxysphingosine (or 6-hydroxysphingenine). Late stages of differentiated keratinocytes produce heterogeneous Cer molecules (at least ten species) due to different combination of sphingoid base and amide-linked FA species, while acylCer are unique to the epidermis.
Figure 2 Updated most likely pathway for acylCer formation (November 2010). AcylCer formation requires unique biochemical steps, which include VLFA synthesis, ω-hydroxylation and ω-O-esterification. ELOVL4 and a cytochrome P-450 enzyme account for VLFA synthesis and ω-hydroxylation, respectively. Linoleic acid, an essential FA, is a predominant lipid species in ω-O-esterified FA. CE, cornified envelope; LA, linoleic acid; Sp, sphingoid base; and DGAT2, acylCoA:diacylglycerol acyltransferase 2.
