Apoptosis: BH1-4 Domain
The BH1-4 domain of Bcl-xL bound to Bak peptide (red).
Domain Binding and Function
Bcl-2 Homology (BH1–4) domains are found in proteins that inhibit apoptosis including Bcl-2, Bcl-xL and Bcl-xW. Bcl-2 family members form homodimers and heterodimers between pro- and antiapoptotic family members. Homodimerization of Bcl-2 involves a head-totail interaction. The N-terminal region, where the BH4 domain resides, interacts with the more distal region of Bcl-2 where BH1, BH2 and BH3 are located. The BH3 domain is required for dimerization and apoptosis induction. Conversely, Bcl-2/Bax heterodimerization involves a tail-to-tail interaction that requires the BH1, BH2 and BH3 region of Bcl-2 and a central region in Bax where the BH3 domain is located.
Structure Reference
- Sattler, M. et al. (1997) Science 275(5302), 983–986.
Examples of Domain Proteins
Binding Examples
| BH1-4 Domain Proteins | Binding Partners |
|---|---|
| Bcl-2, Bcl-xL (BH1, BH2, BH3) | Bax, Bad (BH3) |
| Bcl-2 (BH4) | Bcl-2 (BH1, BH2, BH3) |
