Download MendeleyDiphosphothreonine-specific interaction between an SQ/TQ cluster and an FHA domain in the Rad53-Dun1 kinase cascade.
Lee, H., Yuan, C., Hammet, A., Mahajan, A., Chen, E.S., Wu, M.R., Su, M.I., Heierhorst, J., Tsai, M.D.(2008) Mol Cell 30: 767-778
- PubMed: 18570878
- DOI: https://doi.org/10.1016/j.molcel.2008.05.013
- Primary Citation of Related Structures:
2JQI, 2JQJ, 2JQL - PubMed Abstract:
Forkhead-associated (FHA) domains recognize phosphothreonines, and SQ/TQ cluster domains (SCDs) contain concentrated phosphorylation sites for ATM/ATR-like DNA-damage-response kinases. The Rad53-SCD1 has dual functions in regulating the activation of the Rad53-Dun1 checkpoint kinase cascade but with unknown molecular mechanisms. Here we present structural, biochemical, and genetic evidence that Dun1-FHA possesses an unprecedented diphosphothreonine-binding specificity. The Dun1-FHA has >100-fold increased affinity for diphosphorylated relative to monophosphorylated Rad53-SCD1 due to the presence of two separate phosphothreonine-binding pockets. In vivo, any single threonine of Rad53-SCD1 is sufficient for Rad53 activation and RAD53-dependent survival of DNA damage, but two adjacent phosphothreonines in the Rad53-SCD1 and two phosphothreonine-binding sites in the Dun1-FHA are necessary for Dun1 activation and DUN1-dependent transcriptional responses to DNA damage. The results uncover a phospho-counting mechanism that regulates the specificity of SCD, and provide mechanistic insight into a role of multisite phosphorylation in DNA-damage signaling.
Organizational Affiliation:
Genomics Research Center, Academia Sinica, Taipei 115, Taiwan.
