title: A novel non-canonical forkhead-associated (FHA) domain-binding interface mediates the interaction between Rad53 and Dbf4 proteins.
abstract: Forkhead-associated (FHA) and BRCA1 C-terminal (BRCT) domains are overrepresented in DNA damage and replication stress response proteins. They function primarily as phosphoepitope recognition modules but can also mediate non-canonical interactions. The latter are rare, and only a few have been studied at a molecular level. We have identified a crucial non-canonical interaction between the N-terminal FHA1 domain of the checkpoint effector kinase Rad53 and the BRCT domain of the regulatory subunit of the Dbf4-dependent kinase that is critical to suppress late origin firing and to stabilize stalled forks during replication stress. The Rad53-Dbf4 interaction is phosphorylation-independent and involves a novel non-canonical interface on the FHA1 domain. Mutations within this surface result in hypersensitivity to genotoxic stress. Importantly, this surface is not conserved in the FHA2 domain of Rad53, suggesting that the FHA domains of Rad53 gain specificity by engaging additional interaction interfaces beyond their phosphoepitope-binding site. In general, our results point to FHA domains functioning as complex logic gates rather than mere phosphoepitope-targeting modules.
authors.affiliation: From the Departments of Biochemistry and Biomedical Sciences and.
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Matthews
authors.forename: Rajeevan
authors.initials: R
authors.lastname: Selvaratnam
authors.forename: Darryl R
authors.initials: DR
authors.lastname: Jones
authors.forename: Madoka
authors.initials: M
authors.lastname: Akimoto
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: McConkey
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Melacini
authors.forename: Bernard P
authors.initials: BP
authors.lastname: Duncker
authors.forename: Alba
authors.initials: A
authors.lastname: Guarné
mesh_terms: D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D064447:Checkpoint Kinase 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019295:Computational Biology; D004249:DNA Damage / Q000502:physiology; D004261:DNA Replication / Q000502:physiology; D051858:Forkhead Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D018816:Genes, cdc / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D054730:Protein Interaction Domains and Motifs / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; C088096:Dbf4 protein, S cerevisiae; D051858:Forkhead Transcription Factors; D029701:Saccharomyces cerevisiae Proteins; C104169:DUN1 protein, S cerevisiae; D064447:Checkpoint Kinase 2; D017346:Protein Serine-Threonine Kinases; C067022:RAD53 protein, S cerevisiae
keywords: Bioinformatics; Checkpoint Control; DNA Damage Response; DNA Replication; NMR; Protein Domains; Protein-Protein Interactions; Yeast Genetics