Processing of native caspase-14 occurs at an atypical cleavage site in normal epidermal differentiation.
Caspase-14, a cysteinyl aspartate-specific protease expressed during epidermal differentiation, is detected exclusively in the cytosolic fraction of epidermis as a complex of procaspase-14 together with caspase-14 large and small subunits. On non-denaturing protein gels, native caspase-14 has a relative electrophoretic mobility of approximately 80kDa, which resolves into caspase-14 proform, large and small subunit in SDS-polyacrylamide. Purification of caspase-14 from native skin with subsequent N-terminal sequencing of the small subunit and tryptic digest analysis of the large subunit revealed an atypical processing site between Ile152 and Lys153, which distinguishes it from other caspases described to date that are processed at aspartate residues. Expression of caspase-14 in heterologous systems results in unprocessed procaspase-14 without generation of the large and small subunits that characterize this protein family. However, addition of cellular extracts to purified recombinant human caspase-14 generated immunoreactive peptides indistinguishable from large and small subunits in skin. These data provide evidence for novel processing of caspase-14 suggesting that this enzyme has unique mechanisms of regulation during epidermal differentiation.
Division of Dermatology, Department of Medicine, University of Washington, Box 357132, Seattle, WA 98195-7132, USA.
Andy J
AJ
Chien
Richard B
RB
Presland
Melanie K
MK
Kuechle
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002154:Calpain / Q000378:metabolism; D053456:Caspase 14; D020169:Caspases / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000201:enzymology*; D006801:Humans; D015151:Immunoblotting; D015603:Keratinocytes / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014357:Trypsin / Q000494:pharmacology
D004792:Enzyme Precursors; D011994:Recombinant Proteins; D014357:Trypsin; C506446:CASP14 protein, human; D002154:Calpain; C506449:Casp14 protein, mouse; D053456:Caspase 14; D020169:Caspases