title: Versatility in phospho-dependent molecular recognition of the XRCC1 and XRCC4 DNA-damage scaffolds by aprataxin-family FHA domains.
abstract: Aprataxin, aprataxin and PNKP-like factor (APLF) and polynucleotide kinase phosphatase (PNKP) are key DNA-repair proteins with diverse functions but which all contain a homologous forkhead-associated (FHA) domain. Their primary binding targets are casein kinase 2-phosphorylated forms of the XRCC1 and XRCC4 scaffold molecules which respectively coordinate single-stranded and double-stranded DNA break repair pathways. Here, we present the high-resolution X-ray structure of a complex of phosphorylated XRCC4 with APLF, the most divergent of the three FHA domain family members. This, combined with NMR and biochemical analysis of aprataxin and APLF binding to singly and multiply-phosphorylated forms of XRCC1 and XRCC4, and comparison with PNKP reveals a pattern of distinct but overlapping binding specificities that are differentially modulated by multi-site phosphorylation. Together, our data illuminate important differences between activities of the three phospho-binding domains, in spite of a close evolutionary relationship between them.
authors.affiliation: Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Cherry
authors.affiliation: Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Nott
authors.affiliation: MRC Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, UK.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Kelly
authors.affiliation: MRC Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, UK.
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Rulten
authors.affiliation: MRC Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, UK.
authors.forename: Keith W
authors.initials: KW
authors.lastname: Caldecott
authors.affiliation: Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK. Electronic address: Steve.Smerdon@crick.ac.uk.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Smerdon
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D047390:Casein Kinase II / Q000378:metabolism; D018360:Crystallography, X-Ray; D004249:DNA Damage; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000648:ultrastructure; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000737:chemistry* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009687:Nuclear Proteins / Q000737:chemistry*; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000648:ultrastructure; D000075223:Poly-ADP-Ribose Binding Proteins; D017434:Protein Structure, Tertiary; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: C438188:APTX protein, human; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; C101467:XRCC4 protein, human; C530380:PNKP protein, human; D017853:Phosphotransferases (Alcohol Group Acceptor); D047390:Casein Kinase II; C520557:APLF protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D045643:DNA Repair Enzymes
keywords: DNA break repair; DNA-damage signalling; FHA domain