Keratin, type I cytoskeletal 18 (UniProt P05783; also known as Cell proliferation-inducing gene 46 protein, CK-18, Cytokeratin-18, K18, Keratin-18) is encoded by the KRT18 (also known as CYK18, PIG46) gene (Gene ID 3875) in human. Cytokeratin-18 (Keratin-18 or K18) belongs to a family of highly conserved epithelial-specific intermediate filament (IF) proteins that play an important role in the mechanical stability and integrity of epithelial cells and tissues. Each epithelium is characterized by its unique keratin expression pattern. All epithelial cells typically express at least one type-I and one type-II keratin, which form noncovalent heteropolymers. Keratin 18 is a type I intermediate filament protein that pairs with keratin 8 (K8/K18) in simple epithelia and plays an important role in protecting cells from stress, injury, and apoptosis. K18 is the only type-I keratin in adult hepatocytes and the major type-I keratin in many colonic tumor cell lines.The structure and function of K8/18 are regulated by posttranslational modifications, such as glycosylation, ubiquitination, and phosphorylation, including K8 phosphorylation on Ser8, Ser23, Ser73, Ser431, and K18 phosphorylation on Ser33 and Ser52. K18 phosphorylation has been proposed as a progression marker for human chronic hepatitis B (CHB). Progressively higher Ser52 phosphorylation is reported in non-cirrhotic and cirrhotic CHB livers, and progressive increase of Ser33 and Ser52 phosphorylation correlates with the elevation of both histological lesions and enzymatic activities of alanine aminotransferase in non-cirrhotic CHB livers.，官网链接：https://www.sigmaaldrich.cn/product/mm/abt1383 默克 科研、开发、生产。 作为生命科学行业的全球领先供应商，我们致力于为科研、生物技术开发和生产，以及制药药物疗法开发和生产提供各类解决方案和服务。

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