Formation and functions of the corneocyte lipid envelope (CLE)

• The corneocyte lipid envelope coats the external surface of corneocytes.
• The CLE is made of ω-hydroxyceramides bound to proteins in the corneocyte envelope.
• Both the origin and the function of the CLE are still uncertain.
• Certain disorders of lipid metabolism impact CLE structure.
• The CLE may function as a scaffold that organizes extracellular lamellar bilayers.

Corneocytes in mammalian stratum corneum are surrounded by a monolayer of covalently bound ω-OH-ceramides that form the corneocyte (-bound) lipid envelope (CLE). We review here the structure, composition, and possible functions of this structure, with insights provided by inherited and acquired disorders of lipid metabolism. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.