Anti-phospho-cytokeratin-18 (K18) (Ser33) Antibody, clone IB4 clone IB4, from mouse

Keratin, type I cytoskeletal 18 (UniProt: P05783; also known as Cell proliferation-inducing gene 46 protein, Cytokeratin-18, CK-18, Keratin-18, K18) is encoded by the KRT18 (also known as CYK18, PIG46) gene (Gene ID: 3875) in human. Cytokeratin-18 is a type I, acidic, protein that is expressed in colon, placenta, and liver. Higher expression levels have been reported in lymph nodes of breast carcinoma. Cytokeratin-18 is involved in the uptake of thrombin-antithrombin complexes by hepatic cells. Upon phosphorylation, it plays a role in filament reorganization. It is proteolytically cleaved by caspases during epithelial cell apoptosis and this cleavage is shown to occur at Asp-238. Phosphorylation of cytokeratin-18 at serine 33 is shown to increase during mitosis in cultured cells and in regenerating liver. Serine 33 phosphorylation is considered to be essential for its association with 14-3-3 proteins and has a role in keratin organization and distribution. Cytokeratin-18 can undergo O-glycosylation, which results in its increased solubility and reduction in its stability. Mutations in KRT18 gene are known to cause liver cirrhosis characterized by severe panlobular liver-cell swelling with Mallory body formation, prominent pericellular fibrosis, and marked deposits of copper.