{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Cytokeratins are intermediate-filament keratins found in the intracytoplasmic cytoskeleton of epithelial tissue. There are two types of cytokeratins: acidic type I cytokeratins and basic or neutral type II cytokeratins. Cytokeratins are usually found in pairs comprising a type I cytokeratin and a type II cytokeratin. Expression of these cytokeratins is frequently organ or tissue specific. Cytokeratin 8 (CK 8) is an intermediate filament protein produced early in embryogenesis. CK 8 is a type II basic cytokeratin, often dimerizes with cytokeratin 18 (CK 18), a type I acidic cytokeratin to form intermediate-sized filaments in simple single-layered epithelial cells. CK 8 plays a role in maintaining the structural integrity of epithelial cells, as well as being involved in signal transduction and cellular differentiation. Its expression varies across tissues and can be used as a tool for differentiating between different epithelial cell types."}]}]}