There are at least three-cytoskeletal systems in eukaryotic cells; the intermediate filament (IF) protein family is most complex. Depending on their polymerization properties and tissue specificity they are divided into six subtypes. Intermediate filaments of type-I and type-II are cytokeratin. Cytokeratin are also classified based on the expression as simple epithelial and sratified seqamous cytokine. Cytokeratins are mainly involved in the protection of epithelial cells from mechanical and non-mechanical stresses that resulting in cell death. Human Keratin, type-I cytoskeletal 19 (KRT19) gene encodes the type I intermediate filament chain keratin 19. The type I cytokeratins consist of acidic proteins, which are arranged in pairs of heterotypic keratin chains. Unlike its related family members, KRT19, smallest known acidic cytokeratin is not paired with a basic cytokeratin in epithelial cells. It is specifically expressed in the periderm, the transiently superficial layer that envelopes the developing epidermis. Recent report indicated that detection of blood sample KRT19 (CYFRA21.1) could be used for early stage diagnosis of lung cancer.

Full-length human KRT19 cDNA (399aa, derived from BC067744) was constructed with codon optimization and expressed with a small T7-His-TEV cleavage site Tag (29aa) fusion at its N-terminal. This protein was expressed in E.coli as inclusion bodies. The final product was refolded using our unique “temperature shift inclusion body refolding” technology and chromatographically purified.

1. May be used for in vitro KRT19 mediated cellular cytoskeletal polymerization regulation study for cell stress induced apoptosis by intracellular delivery of this protein with “ProFectin” reagent.

2. May be used protein-protein interaction assay.

3. Potential biomarker protein for clinical applications such as monitoring lung cancer progression by measuring tissue KRT19 protein level in blood or tumor samples.

4. As antigen for specific antibody production.