Metacaspase 2 of Trypanosoma brucei is a calcium-dependent cysteine peptidase active without processing

FEBS Lett. 2007 Dec 11;581(29):5635-9. doi: 10.1016/j.febslet.2007.11.009. Epub 2007 Nov 20.


Metacaspases are cysteine peptidases that are distantly related to the caspases, for which proteolytic processing is central to their activation. Here, we show that recombinant metacaspase 2 (MCA2) from Trypanosoma brucei has arginine/lysine-specific, Ca(2+)-dependent proteolytic activity. Autocatalytic processing of MCA2 occurred after Lys55 and Lys268; however, this was shown not to be required for the enzyme to be proteolytically active. The necessity of Ca(2+), but not processing, for MCA2 enzymatic activity clearly distinguishes MCA2 from the caspases and would be consistent with different physiological roles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arginine / metabolism
  • Calcium / metabolism*
  • Caspases / metabolism
  • Cysteine Endopeptidases / metabolism*
  • Lysine / metabolism
  • Mutagenesis, Site-Directed
  • Protozoan Proteins / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Trypanosoma brucei brucei / enzymology*
  • Trypanosoma brucei brucei / metabolism


  • Protozoan Proteins
  • Recombinant Proteins
  • Arginine
  • Caspases
  • Cysteine Endopeptidases
  • Lysine
  • Calcium