Intermediate filaments (IFs), together with actin microfilaments and tubulin microtubules, comprise the three major cytoskeletal networks that are found in most eukaryotic cells.1 Keratins, which are the largest IF protein subgroup, can be divided into the acidic type I (K9-K20) and basic type II (K1-K8) keratins.2 Typically, epithelial cells express at least one of each type, and the proteins exist in the cells as noncovalent obligate heteropolymers. Keratin networks are highly dynamic and reorganized during cell differentiation, mitosis and apoptosis, and also play important cytoprotective and structural support roles for the cell.3,4 During apoptosis, the epithelial keratins 18/19 undergo caspase-mediated proteolysis, leading to the disassembly of the nuclear envelope and cytoplasmic IF networks.5 K18 and K19 undergo caspase-cleavage at the conserved Asp237 in their rod domains.5 In contrast to other type I keratins, K18 is unique in that it includes another caspase-cleavage site at Asp396 of the carboxy-terminal domain.6
Rabbit anti-human K18 (IN-2) polyclonal antibody was raised against a synthetic peptide corresponding to an internal sequence of human keratin-18. This epitope affinity purified rabbit polyclonal antibody reacts predominantly with human keratin-18. Western blot using HT29 cell lysate from human colonic carcinoma shows a 49 kDa immunoreactive protein. Human, mouse, and monkey reactive. Predicted to detect dog, bovine, and frog keratin -18.
Rabbit anti-human K19 (IN) polyclonal antibody was raised against a synthetic peptide corresponding to an internal sequence of human keratin-19. This epitope affinity purified rabbit polyclonal antibody reacts predominantly with human keratin-19. Western blot using HT29 cell lysate from human colonic carcinoma shows a ~45 kDa immunoreactive protein. Human, mouse, chimpanzee, and monkey reactive. Predicted to detect rat and bovine keratin-19.
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3. Omary, MB. et al. et al. Trends Biochem. Sci. 31, 383 (2006)
4. Omary, MB. et al. N. Engl. J. Med. 351, 2087 (2004)
5. Ku, NO. et al. J. Biol. Chem. 272, 33197 (1997)
6. Ku, NO. and MB. Omary, J. Biol. Chem. 276, 26792 (2001)