Details:
Interacting selectively and non-covalently with the BH4 domain of a protein of the Bcl-2 family. All anti-apoptotic proteins contain BH1 and BH2 domains; some also contain an additional N-terminal BH4 domain, which is almost never seen in pro-apoptotic proteins. Loss of the BH4 domain can diminish or abrogate anti-apoptotic function or even impart outright death-promoting properties to the protein. [InterPro:IPR003093, PMID:11048732, PMID:12133724, PMID:9020082, PMID:9704409, Prosite:PS01260, Prosite:PS50063]