Mechanism of κB DNA binding by Rel/NF-κB dimers*

By C. Phelps, L. L. Sengchanthalangsy, S. Malek, G. Ghosh. Journal of Biological Chemistry, 2000

116 citations recorded by the source corpus.

The DNA binding of three different NF-κB dimers, the p50 and p65 homodimers and the p50/p65 heterodimer, has been examined using a combination of gel mobility shift and fluorescence anisotropy assays. The NF-κB p50/p65 heterodimer is shown here to bind the κB DNA target site of the immunoglobulin κ enhancer (Ig-κB) with an affinity of approximately 10 nm. The p50 and p65 homodimers bind to the same site with roughly 5- and 15-fold lower affinity, respectively. The nature of the binding isotherms indicates a cooperative mode of binding for all three dimers to the DNA targets. We have further characterized the role of pH, salt, and temperature on the formation of the p50/p65 heterodimer-Ig-κB complex. The heterodimer binds to the Ig-κB DNA target in a pH-dependent manner, with the highest affinity between pH 7.0 and 7.5. A strong salt-dependent interaction between Ig-κB and the p50/p65 heterodimer is observed, with optimum binding occurring at monovalent salt concentrations below 75 mm, with binding becoming virtually nonspecific at a salt concentration of 200 mm. Binding of the heterodimer to DNA was unchanged across a temperature range between 4 °C and 42 °C. The sensitivity to ionic environment and insensitivity to temperature indicate that NF-κB p50/p65 heterodimers form complexes with specific DNA in an entropically driven manner.

Subfields: Cancer Research, Immunology

View Paper: https://www.semanticscholar.org/paper/a5281a6969619d23d63751fa6094db3fb5a029cb

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In Cancer Research

1. Alexander Hoffmann
2. G. Natoli
3. S. Ghosh
4. T. Gilmore
5. M. Hayden

In Immunology

1. G. Natoli
2. Alexander Hoffmann
3. S. Ghosh
4. T. Gilmore
5. M. Hayden

Citations in the corpus

• Transcriptional regulation via the NF-κB signaling module (2006, background): “The affinities of physiological IkB–NF-kB complexes are much higher than that of the NF-kB dimers (pM versus nM) (Phelps et al., 2000a, b).”