title: 9-1-1: PCNA's specialized cousin.
abstract: All living organisms are vulnerable to DNA damage. Cells respond to this hazard by activating a complex network of checkpoint and repair proteins to preserve genomic integrity. The DNA-encircling, ring-shaped heterotrimeric 9-1-1 complex, a relative of the replication protein PCNA, is a central coordinator of these events. 9-1-1 is loaded to damaged sites where it serves as a platform for the selective recruitment of checkpoint and repair proteins. In this Opinion article, 9-1-1 and proliferating cell nuclear antigen (PCNA) are compared and discussed in light of their respective structures and functions. We propose that the interaction partners of 9-1-1 possess specific 9-1-1-interaction boxes, which discriminate between 9-1-1 and PCNA thereby enabling specific interactions with individual 9-1-1 subunits.
authors: Department of Biochemistry University of Oxford, South Parks Road, Oxford OX1 3QU, UK. christian.eichinger@bioch.ox.ac.uk
authors: Christian S
authors: CS
authors: Eichinger
authors: Stefan
authors: S
authors: Jentsch
mesh_terms: D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D005092:Exonucleases / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; C549605:HUS1 protein, human; D018809:Proliferating Cell Nuclear Antigen; C069930:rad9 protein; D005092:Exonucleases; C113574:Rad1 protein, human