cornified envelope

Definition

Target type: cellularcomponent

A type of plasma membrane that has been modified through addition of distinct intracellular and extracellular components, including ceramide, found in cornifying epithelial cells (corneocytes). [GOC:add, PMID:11112355, PMID:11590230, PMID:15803139]

The cornified envelope (CE) is a specialized, highly cross-linked protein structure that forms the outermost layer of the stratum corneum in vertebrate skin. It provides a barrier against environmental insults and contributes to the skin's mechanical strength. The cellular component of the CE is a complex mixture of proteins, primarily cytokeratins, cross-linked by transglutaminase enzymes. The major cytokeratins involved in CE formation are cytokeratins 1 and 10, which are expressed in the upper layers of the epidermis and are specifically upregulated in differentiating keratinocytes. These cytokeratins are synthesized as precursors, which are then processed and assembled into intermediate filaments. During the terminal differentiation of keratinocytes, the intermediate filaments undergo extensive cross-linking through the action of transglutaminases, primarily transglutaminase 1 (TG1). TG1 is a calcium-dependent enzyme that catalyzes the formation of isopeptide bonds between specific lysine and glutamine residues in the cytokeratins, leading to the formation of a rigid, insoluble network. In addition to cytokeratins, other proteins have been found to be incorporated into the CE, including loricrin, involucrin, and small proline-rich proteins (SPRRs). These proteins contribute to the structural integrity and barrier function of the CE. The formation of the CE is a tightly regulated process that is essential for skin barrier function. Defects in CE formation can lead to skin disorders, such as ichthyosis and epidermolytic hyperkeratosis. The CE is a unique and complex cellular component that plays a critical role in skin biology.'
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Proteins (6)

Compounds (29)