Insights into Rad3 kinase recruitment from the crystal structure of the DNA damage checkpoint protein Rad26.
Publication Type:Journal Article
Source:J Biol Chem, Volume 292, Issue 20, p.8149-8157 (2017)
Keywords:Adenosine Triphosphatases, Crystallography, X-Ray, DNA Helicases, Fungal Proteins, Multienzyme Complexes, Protein Multimerization, Protein Structure, Quaternary, Repetitive Sequences, Amino Acid, Sordariales
<p>Metabolic products and environmental factors constantly damage DNA. To protect against these insults and maintain genome integrity, cells have evolved mechanisms to repair DNA lesions. One such mechanism involves Rad3, a master kinase coordinating the DNA damage response. Rad26 is a functional subunit of the Rad3-Rad26 complex and is responsible for bringing the kinase to sites of DNA damage. Here, I present the crystal structure of Rad26 and identify the elements important for recruiting Rad3. The structure suggests that Rad26 is a dimer with a conserved interface in the N-terminal part of the protein. Biochemical data showed that Rad26 uses its C-terminal domain and the flanking kinase-docking motif to bind specific HEAT repeats in Rad3. Analysis of the reconstituted Rad3-Rad26 heterotetrameric complex with electron microscopy enabled me to propose a structural model for its quaternary structure. In conclusion, these results suggest that Rad26 exists as a dimer and provide crucial insight into how Rad3 is recruited and incorporated into the Rad3-Rad26 DNA repair complex.</p>