Apoptosis-induced cleavage of keratin 15 and keratin 17 in a human breast epithelial cell line.
Keratin 15 (K15) and keratin 17 (K17) are intermediate filament (IF) type I proteins that are responsible for the mechanical integrity of epithelial cells. By analyzing the human breast epithelial cell line H184A1 before and after induction of apoptosis by high-resolution two-dimensional gel electrophoresis (2-DE) we identified the caspase-mediated cleavage of keratins 15 and 17. After induction of apoptosis three fragments of both K15 and K17 could be observed by 2 -DE. K15 and K17 proteolysis was observed during staurosporine-induced apoptosis and anoikis (anchorage-dependent apoptosis) as well and was shown to be caspase-dependent. By using mass spectrometry we could determine the caspase cleavage sites, one in K15 and two in K17. The sequence VEMD/A at the cleavage site located in the conserved linker region was found in K15 and K17. A further cleavage site was identified in the tail region of K17 with the recognition motif EVQD/G.
Badock
V
V
Department of Protein Chemistry, Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Str. 10, D-13092 Berlin, Germany.
Steinhusen
U
U
Bommert
K
K
Wittmann-Liebold
B
B
Otto
A
A
D000595:Amino Acid Sequence; D017209:Apoptosis / Q000502:physiology*; D001665:Binding Sites; D015153:Blotting, Western; D001940:Breast / Q000166:cytology* / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism; D053569:Keratin-15; D007633:Keratins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010449:Peptide Mapping
D007527:Isoenzymes; C116015:KRT15 protein, human; D053569:Keratin-15; D007633:Keratins; D020169:Caspases