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Evaluation of Caspase Activation to Assess Innate Immune Cell Death
Published on: January 20, 2023
Caspase 12 in calnexin-deficient cells
Jody Groenendyk1, Anna Zuppini, Gordon Shore
1Membrane Protein Research Group, University of Alberta, Edmonton, Alberta, Canada.
Biochemistry
|November 1, 2006
Summary
Calnexin deficiency confers resistance to endoplasmic reticulum stress-induced apoptosis. Calnexin, caspase 12, and Bap31 interact to modulate cellular sensitivity to ER stress.
Area of Science:
- Cellular Biology
- Molecular Biology
- Apoptosis Research
Background:
- Endoplasmic reticulum (ER) stress is implicated in various cellular pathologies.
- The molecular mechanisms governing ER stress-induced apoptosis are complex and not fully elucidated.
- Calnexin is a key chaperone protein involved in ER function.
Purpose of the Study:
- To investigate the role of calnexin, caspase 12, and Bap31 in ER stress-induced apoptosis.
- To determine how calnexin deficiency affects cellular sensitivity to ER stress.
- To elucidate the interplay between calnexin, caspase 12, and Bap31 during ER stress.
Main Methods:
- Utilized calnexin-deficient mouse embryonic fibroblasts and a human T cell line (NKR).
- Employed Western blot analysis to assess protein expression and cleavage.
- Conducted immunoprecipitation experiments to identify protein interactions within the ER.
Main Results:
- Calnexin-deficient cells exhibited relative resistance to ER stress-induced apoptosis.
- Caspase 12 was present in both wild-type and calnexin-deficient cells, with slightly inhibited expression and specific cleavage in deficient cells.
- Calnexin, caspase 12, and Bap31 form complexes in the ER; Bap31 cleavage upon ER stress was dependent on calnexin presence.
- Caspase 8 processing was negligible in calnexin-deficient cells.
Conclusions:
- Calnexin plays a crucial role in modulating cellular sensitivity to ER stress-induced apoptosis.
- The interaction of calnexin with caspase 12 and Bap31 is critical for the apoptotic pathway activation.
- Calnexin deficiency impairs Bap31 cleavage and caspase 8 processing, contributing to apoptosis resistance.
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