Study on the expression of IkappaB-alpha protein in TNF-alpha induced apoptosis of U937 cells
Related Experiment Video
Updated: May 23, 2026

Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling
Published on: June 25, 2015
Weihua Chen1, Guangjie Peng, Aiping Tang
1Department of Pediatrics, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
Objective:
To investigate the TNF-alpha induced apoptosis of U937 cells, the expression, degradation and subcellular localization of IkappaB-alpha, and its degradation mechanism.
Method:
Changes and subcellular loca-lization of IkappaB-alpha were observed by fluorescence microscopy, expression and degradation of IkappaB-alpha protein with N-tosyl-L-phenylalanylchloromethyl ketone (TPCK protease inhibitor) blocking test and apoptosis of U937 cell by flow cytometry.
Results:
(1) immunolfluorescence assay showed that IkappaB-alpha localized in cytoplasm only. (2) The level of IkappaB-alpha protein was downregulated after TNF-alpha stimulation, flow cytometry also confirmed the downregulation. (3) The downregulation of IkappaB-alpha protein levels in TNF-alpha induced apoptosis was partially inhibited by TPCK. (4) The apoptosis rate of U937 cells induced by TNF-alpha was (60.73 +/- 1.61)%.
Conclusion:
(1) Degradation of IkappaB-alpha protein during TNF-alpha induced apoptosis of U937 cells suggested the activation of NF-kappaB. (2) TPCK sensitive protease plays an important role in the degradation of IkappaB-alpha protein. (3) TPCK sensitive protease also involved in the apoptosis of U937 cells induced by TNF-alpha.
More Related Videos
Related Concept Videos
NF-κB-dependent Signaling Pathway
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
Caspases
The Extrinsic Apoptotic Pathway
The Intrinsic Apoptotic Pathway
Cellular Injury IlI: Cellular Death
Cellular Injury V: Apoptosis and Autophagy

