Korean J Lab Med.  2005 Jun;25(3):192-198.

C-Terminal Serine Rich Region of IKK-beta Interacts with Bfl-1, a Homologue of Bcl-2

• Yoon HK
• Kim JK
• Cho HJ
• Cho MY
• Park YP
• You KH
• Kim JW
• Yoon DY
• Choe YK
• Lee HG

Abstract

BACKGROUND
Bcl-2 family proteins play a central role in regulating apoptosis. In human, over 20 members of this family have been identified to date. Bfl-1, a member of the Bcl-2 family, has been known to retard apoptosis in various cell lines. However, the function of Bfl-1 remains unclear. METHODS: In order to investigate the Bfl-1 function, we employed yeast two-hybrid system to identify the proteins which are capable of interacting with Bfl-1. The interaction of inhibitor kappaB kinase-beta (IKK-beta) and Bfl-1 was confirmed using glutathione S-transferase pull down assays. To determine which regions of IKK-beta were required for interaction with Bfl-1, we constructed 12 deletion mutants of IKK-beta and 5 deletion mutants of Bfl-1. RESULTS: Bfl-1 interacted with the C-terminal region of IKK-beta which is a subunit of IKK complex, and IKK-beta activity is very important in the NF-kappaB related pathway. In addition, the amino acids 673-745 of IKK-beta were important for Bfl-1 interactions, and amino acids 1-484 of Bfl-1, including Bcl-2 homology domains (BH1, BH2, BH3, BH4), were crucial for IKK-beta interactions. CONCLUSIONS: IKK beta C-terminus contains many serine residues as binding partner of Bfl-1. Our results suggested that Bfl-1 is involved in the NF-kappaB activation through interaction of IKK-beta and Bfl-1. Further studies need to be performed to understand functions of the IKK-beta and Bfl-1 associated with the regulation of the NF-kappaB activation pathway.

Keyword

Bfl-1; IKK-beta yeast two hybrid; BH domain

MeSH Terms

Amino Acids
Apoptosis
Cell Line
Glutathione Transferase
Humans
I-kappa B Kinase
NF-kappa B
Serine*
Two-Hybrid System Techniques
Amino Acids
Glutathione Transferase
I-kappa B Kinase
NF-kappa B
Serine