Mutagenesis of the Runt Domain Defines Two Energetic Hot Spots for Heterodimerization with the Core Binding Factor β Subunit

• Published in: The Journal of biological chemistry 2003-08, Vol.278 (35), p.33097
• Main Authors: Lina Zhang, Zhe Li, Jiangli Yan, Padmanava Pradhan, Takeshi Corpora, Matthew D. Cheney, Jerónimo Bravo, Alan J. Warren, John H. Bushweller, Nancy A. Speck
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M303972200

Core-binding factors (CBFs) are a small family of heterodimeric transcription factors that play critical roles in several developmental pathways and in human disease. Mutations in CBF genes are found in leukemias, bone disorders, and gastric cancers. CBFs consist of a DNA-binding CBFα subunit (Runx1, Runx2, or Runx3) and a non-DNA-binding CBFβ subunit. CBFα binds DNA in a sequence-specific manner, whereas CBFβ enhances DNA binding by CBFα. Both DNA binding and heterodimerization with CBFβ are mediated by a single domain in the CBFα subunits known as the “Runt domain.” We analyzed the energetic contribution of amino acids in the Runx1 Runt domain to heterodimerization with CBFβ. We identified two energetic “hot spots” that were also found in a similar analysis of CBFβ (Tang, Y.-Y., Shi, J., Zhang, L., Davis, A., Bravo, J., Warren, A. J., Speck, N. A., and Bushweller, J. H. (2000) J. Biol. Chem. 275, 39579–39588). The importance of the hot spot residues for Runx1 function was demonstrated in in vivo transient transfection assays. These data refine the structural analyses and further our understanding of the Runx1-CBFβ interface.