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Updated: May 10, 2026
08:35
Examining BCL-2 Family Function with Large Unilamellar Vesicles
Published on: October 5, 2012
tBid undergoes multiple conformational changes at the membrane required for Bax activation.
Aisha Shamas-Din1, Scott Bindner, Weijia Zhu
1Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada.
The Journal of Biological Chemistry
|June 8, 2013
Summary
The Bcl-2 family protein Bid splits into p7 and tBid fragments upon apoptotic stimuli. Mtch2 facilitates tBid
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Bid is a Bcl-2 family protein crucial for initiating apoptosis.
- Bid cleavage generates p7 and tBid fragments, which remain associated until membrane interaction.
- The precise mechanism of Bid fragment separation and tBid membrane binding is not fully understood.
Purpose of the Study:
- To elucidate the mechanism of Bid fragment separation upon membrane interaction.
- To investigate the role of tBid conformational changes in Bax activation and MOMP.
- To determine the function of Mtch2 in regulating tBid-mediated apoptosis.
Main Methods:
- Utilized in vitro models with liposomes and isolated mitochondria containing fluorescently labeled proteins.
- Employed physiological protein concentrations to mimic cellular conditions.
- Performed automated high-throughput image analysis in cells to track protein relocalization.
Main Results:
- Bid fragments (p7 and tBid) rapidly separate upon interacting with membranes.
- tBid undergoes conformational changes on the membrane, a prerequisite for Bax interaction.
- Mtch2 down-regulation significantly delays tBid and Bax relocalization, indicating its role in accelerating MOMP.
Conclusions:
- Mtch2 promotes tBid insertion and conformational changes at the mitochondrial outer membrane.
- This action accelerates tBid-mediated Bax activation and mitochondrial outer membrane permeabilization (MOMP).
- The Mtch2-tBid interaction represents a potential therapeutic target for controlling Bid-initiated cell death.
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