Structural highlights 
  Evolutionary Conservation 
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
  Publication Abstract from PubMed 
Rad9, Rad1, and Hus1 form a heterotrimeric complex (9-1-1) that is loaded onto DNA at sites of DNA damage. DNA-loaded 9-1-1 activates signaling through the Chk1 arm of the DNA damage checkpoint response via recruitment and stimulation of ATR. Additionally, 9-1-1 may play a direct role in facilitating DNA damage repair via interaction with a number of DNA repair enzymes. We have now determined the crystal structure of the human 9-1-1 complex, revealing a toroidal structure with a similar architecture to the homotrimeric PCNA DNA-binding clamp. The structure explains the formation of a unique heterotrimeric arrangement and reveals significant differences among the three subunits in the sites implicated in binding to the clamp loader and to ligand proteins. Biochemical analysis reveals a single repair enzyme-binding site on 9-1-1 that can be blocked competitively by the PCNA-binding cell-cycle regulator p21(cip1/waf1).
Crystal structure of the rad9-rad1-hus1 DNA damage checkpoint complex--implications for clamp loading and regulation.,Dore AS, Kilkenny ML, Rzechorzek NJ, Pearl LH Mol Cell. 2009 Jun 26;34(6):735-45. Epub 2009 May 14. PMID:19446481[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
 
  References 
- ↑ Dore AS, Kilkenny ML, Rzechorzek NJ, Pearl LH. Crystal structure of the rad9-rad1-hus1 DNA damage checkpoint complex--implications for clamp loading and regulation. Mol Cell. 2009 Jun 26;34(6):735-45. Epub 2009 May 14. PMID:19446481 doi:10.1016/j.molcel.2009.04.027