Involucrin (F9C3C) Rabbit Monoclonal Antibody #29665

Involucrin is a marker of terminal keratinocyte differentiation in stratified squamous epithelia and a component of the cross-linked cornified cell envelope (CE) adjacent to the plasma membrane (1,2). The high number of glutamine-rich repeats in the amino acid sequence of involucrin serve as active sites for the cross-linking enzyme transglutaminase (1-3). Soluble involucrin can be cross-linked to itself and other members of the CE, including cystatin alpha, loricrin, elafin, desmoplakin family proteins, spr family proteins, and keratin family proteins (3). The CE can be reconstituted in vitro in 3D bioprinted artificial human skin expressing IVL, or with cultured keratinocytes in the presence of Ca⁺⁺ and transglutaminase (4,5). While the CE is insoluble and highly resistant to detergent extraction, cross-linked involucrin can be cleaved in vitro using cyanogen bromide (6). Mice deficient in involucrin, envoplakin, and periplakin develop dry, hyperkeratotic skin with underlying structurally abnormal CEs (7). Involucrin is overexpressed in transcription factor Foxn1-/- nude mice, one of several PKC-driven differentiation abnormalities in this model (8). Frequent coexpression of PTK6/BRK and involucrin has been observed in breast cancer tissue, and these proteins can serve as predictive biomarkers for therapeutic response to vitamin D3 (9). In squamous cell carcinoma (SCC), involucrin expression is inversely correlated with retinal G protein-coupled receptor (RGR) expression, with involucrin expression higher in well-differentiated SCC lesions (10).