Involucrinrelated

Involucrin-related refers to a proposed class of epidermal proteins that show sequence similarity to involucrin (IVL), the major cross-linking substrate in the cornified envelope of differentiating keratinocytes. The term is used in various databases and studies to describe proteins designated as “involucrin-related” or “IVL-related” when they share homology with involucrin but are not the canonical IVL gene, or when they represent divergent family members across species. Membership in the group is variable and not defined by a single universal naming convention.

Biochemical characteristics of involucrin-related proteins often include cytosolic localization in late differentiating keratinocytes and regions enriched in glutamine and proline, which can serve as substrates for transglutaminase enzymes. Domain organization and length can vary, with some members containing conserved motifs at their termini while others exhibit more repetitive sequences. These features support a role in cross-linking into the cornified envelope, a process that strengthens the outer epidermal barrier.

Biological roles are believed to involve participation in barrier formation and the mechanical resilience of the stratum corneum, complementing involucrin during envelope assembly. Evolutionarily, IVL-related proteins are observed across amniotes and other vertebrates, with gene duplication and divergence contributing to species-specific repertoires and differences in epidermal differentiation.

Clinical relevance and research aspects include associations between altered expression of involucrin and IVL-related proteins and skin barrier dysfunction in disorders such as dermatitis. They are studied through comparative genomics, transcriptomics, and proteomics to elucidate epidermal differentiation and envelope formation. See also involucrin, transglutaminase 1, cornified envelope.