Related Experiment Video
Updated: Jul 5, 2026

Examining BCL-2 Family Function with Large Unilamellar Vesicles
Published on: October 5, 2012
Bax-mediated mitochondrial membrane permeabilization after heat treatment is caspase-2 dependent
E H A Nijhuis1, S Le Gac, A A Poot
1Faculty of Science and Technology, Department of Polymer Chemistry and Biomaterials, University of Twente, Institute of Biomedical Technology (BMTI), Enschede, The Netherlands.
Abstract:
Heat-induced apoptosis proceeds via mitochondria by permeabilization of the outer mitochondrial membrane (MOMP), resulting in the release of cytochrome c. This essential step is mediated by Bcl-2 family proteins, such as Bax. Recently, caspase-2 was assigned a prominent role in regulating Bax. Therefore, we studied the initiation of heat-induced apoptosis by monitoring Bcl-2 family members and the release of cytochrome c with or without caspase-2 inhibition. Three hematopoietic cell lines (HSB2, HL60 and Kasumi-1) were exposed to heat treatment and/or X-radiation. Expression and localization of Bax and Bcl-2 proteins was investigated by flow cytometry (FCM) and confocal microscopy respectively. Cytochrome c release was measured with FCM as evidence for MOMP. In addition, the role of caspase-2 in heat- and radiation-induced apoptosis was assessed using the specific caspase-2 inhibitor zVDVAD-fmk. Here we present evidence that heat treatment, and not irradiation, increases intracellular Bax protein expression and subsequently stimulates MOMP, resulting in the release of cytochrome c. Furthermore, by selective blocking of caspase-2 using zVDVAD-fmk less Bax was expressed and subsequently a significant decrease in cytochrome c release was observed. In conclusion, heat treatment of hematopoietic cells does require caspase-2 activation for the initiation of Bax-mediated MOMP.
Related Concept Videos
The Intrinsic Apoptotic Pathway
Caspases
Cellular Injury V: Apoptosis and Autophagy
Apoptosis
The Extrinsic Apoptotic Pathway
Necrosis
Morphological Manifestations of Necrosis
Necrotic cells show different types of morphological appearance depending on the type of tissue and infection. In coagulative necrosis, cells become anucleated and die, but their...

