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Mch3, a novel human apoptotic cysteine protease highly related to CPP32
T Fernandes-Alnemri1, A Takahashi, R Armstrong
1Department of Pharmacology, Jefferson Cancer Institute, Jefferson Medical College, Philadelphia, Pennsylvania 19107, USA.
Cancer Research
|December 15, 1995
Summary
Researchers identified Mch3, a new cysteine protease related to CPP32, involved in apoptosis. Mch3 alpha and CPP32 can form active complexes, suggesting Mch3 contributes to poly(ADP-ribose) polymerase cleavage during programmed cell death.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Mammalian cysteine proteases, homologous to C. elegans CED-3, are crucial for apoptosis.
- CPP32 and Mch2 alpha proteases cleave apoptotic markers PARP and lamins.
Purpose of the Study:
- To clone and characterize a novel Ced-3/ICE-related gene, Mch3.
- To investigate the enzymatic activity and potential role of Mch3 in apoptosis.
Main Methods:
- Cloning of the Mch3 gene and its alternatively spliced isoform, Mch3 beta.
- Bacterial expression and purification of recombinant Mch3 alpha.
- Assays for enzymatic activity, including substrate cleavage and heteromeric complex formation.
- Induction of apoptosis in Sf9 cells using recombinant complexes.
Main Results:
- Mch3 shares high homology with CPP32 and exhibits intrinsic autocatalytic activity.
- Active Mch3 alpha, like CPP32, cleaves PARP and peptide substrates.
- Mch3 alpha and CPP32 can form active heteromeric complexes, suggesting cooperative function.
- CPP32 can cleave proMch3 alpha, indicating a potential regulatory role in Mch3 activation.
Conclusions:
- Mch3 is a novel cysteine protease involved in apoptosis.
- Mch3 alpha contributes to PARP cleavage during apoptosis, alongside CPP32.
- Interplay between Mch3 alpha and CPP32 suggests a complex regulatory network in apoptotic pathways.