The Role of Cytokeratins in Ensuring the Basic Cellular Functions and in Dignosis of Disorders

Cytokeratins are a large group of intermediate filament proteins that form the cytoskeleton of epithelial cells and their appendages (hair, nails). Biochemically, cytokeratins are divided into two main types: acidic and basic. Each cytokeratin pair necessarily contains both acidic and basic cytokeratins in equimolar amounts. This significantly distinguishes cytokeratins from other intermediate filament proteins and is essential for proper organization of the cytoskeleton. Cytokeratins also provide signaling in the cell and participate in cell-cell adhesion, and apoptosis. Today, the general principles of cytokeratin expression at different stages of epithelial cell development are known. The expression of cytokeratins is organ-specific, depending on the type of epithelial cells, the degree of differentiation, and tissue development. Therefore, the cytokeratins profile can be used to diagnose various pathological processes. Special attention in the review is paid to cytokeratins 8, 18, and 19 as possible biomarkers of carcinogenesis.