Activation and substrate specificity of caspase-14

Biochemistry. 2004 Aug 17;43(32):10560-9. doi: 10.1021/bi0498048.


Caspase-14 is a developmentally regulated and tissue restricted member of the caspase family present in mammals. It is mainly found in epidermal keratinocytes and has been hypothesized to be involved in a tissue-specific form of cell senescence, leading to the differentiation of keratinocytes that form the cornified cell layer. However, the substrate specificity, activation mechanism, and function of this caspase have yet to be revealed. We report that caspase-14, in contrast to other caspases, is not produced in active form following expression in Escherichia coli but can be activated by high concentrations of kosmotropic salts. Moreover, proteolytic cleavage is also required since the kosmotropic salts were only effective on the cleaved enzyme. We propose that caspase-14 requires proteolytic cleavage within the catalytic domain, followed by dimerization and ordering of mobile active site loops, to generate a competent enzyme. In the presence of kosmotropic salt, we were able to determine the substrate specificities of mouse and human caspase-14. Surprisingly, the substrate preferences for the human and mouse enzyme are dissimilar. The results obtained with human caspase-14 classify this enzyme as a cytokine activator, but the mouse enzyme shows preferences similar to apical apoptotic caspases.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Apoptosis*
  • Binding Sites
  • Caspase 14
  • Caspases / metabolism*
  • Cells, Cultured / enzymology*
  • Dimerization
  • Enzyme Activation / physiology*
  • Escherichia coli / enzymology
  • Humans
  • Mice
  • Molecular Sequence Data
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Substrate Specificity


  • Recombinant Proteins
  • CASP14 protein, human
  • Casp14 protein, mouse
  • Caspase 14
  • Caspases