Cytokeratin 18 (KRT18) Antibody – Rabbit Monoclonal

KRT18 encodes the type I intermediate filament chain keratin 18. Keratin 18, together with its filament partner keratin 8, are perhaps the most commonly found members of the intermediate filament gene family. They are expressed in single layer epithelial tissues of the body. Mutations in this gene have been linked to cryptogenic cirrhosis. Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008]

Function: Involved in the uptake of thrombin-antithrombin complexes by hepatic cells

By similarity. When phosphorylated, plays a role in filament reorganization. Involved in the delivery of mutated CFTR to the plasma membrane. Together with KRT8, is involved in interleukin-6 (IL-6)-mediated barrier protection. Ref.11 Ref.13 Ref.15 Ref.16 Ref.22 Ref.25 Ref.26

Subunit structure: Heterotetramer of two type I and two type II keratins. KRT18 associates with KRT8. Interacts with the thrombin-antithrombin complex

By similarity. Interacts with PNN, HCV core protein and mutated CFTR. Interacts with YWHAE, YWHAH and YWHAZ only when phosphorylated. Interacts with DNAJB6, TCHP and TRADD. Ref.14 Ref.16 Ref.17 Ref.18 Ref.19 Ref.22 Ref.23

Subcellular location: Cytoplasm › perinuclear region. Nucleus › nucleolus Ref.22 Ref.25 Ref.35.

Tissue specificity: Expressed in colon, placenta, liver and very weakly in exocervix. Increased expression observed in lymph nodes of breast carcinoma. Ref.1 Ref.7 Ref.8 Ref.26

Induction: By IL6/interleukin-6. Ref.26

Post-translational modification: Phosphorylation at Ser-34 increases during mitosis. Hyperphosphorylated at Ser-53 in diseased cirrhosis liver. Phosphorylation increases by IL-6. Ref.11 Ref.14 Ref.16 Ref.21 Ref.25 Ref.26Proteolytically cleaved by caspases during epithelial cell apoptosis. Cleavage occurs at Asp-238 by either caspase-3, caspase-6 or caspase-7. Ref.15O-GlcNAcylation increases solubility, and decreases stability by inducing proteasomal degradation.

Involvement in disease: Cirrhosis (CIRRH) [MIM:215600]: A liver disease characterized by severe panlobular liver-cell swelling with Mallory body formation, prominent pericellular fibrosis, and marked deposits of copper. Clinical features include abdomen swelling, jaundice and pulmonary hypertension.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.37 Ref.38

Miscellaneous: There are two types of cytoskeletal and microfibrillar keratin: I (acidic; 40-55 kDa) and II (neutral to basic; 56-70 kDa).

Sequence similarities: Belongs to the intermediate filament family.