title: Cdc13 OB2 dimerization required for productive Stn1 binding and efficient telomere maintenance.
abstract: Cdc13 is an essential yeast protein required for telomere length regulation and genome stability. It does so via its telomere-capping properties and by regulating telomerase access to the telomeres. The crystal structure of the Saccharomyces cerevisiae Cdc13 domain located between the recruitment and DNA binding domains reveals an oligonucleotide-oligosaccharide binding fold (OB2) with unusually long loops extending from the core of the protein. These loops are involved in extensive interactions between two Cdc13 OB2 folds leading to stable homodimerization. Interestingly, the functionally impaired cdc13-1 mutation inhibits OB2 dimerization. Biochemical assays indicate OB2 is not involved in telomeric DNA or Stn1 binding. However, disruption of the OB2 dimer in full-length Cdc13 affects Cdc13-Stn1 association, leading to telomere length deregulation, increased temperature sensitivity, and Stn1 binding defects. We therefore propose that dimerization of the OB2 domain of Cdc13 is required for proper Cdc13, Stn1, Ten1 (CST) assembly and productive telomere capping.
authors.affiliation: The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA; Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Mason
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania, Stellar-Chance 405A, 422 Curie Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Wanat
authors.affiliation: The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Sandy
authors.initials: S
authors.lastname: Harper
authors.affiliation: The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Schultz
authors.affiliation: The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Speicher
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania, Stellar-Chance 405A, 422 Curie Boulevard, Philadelphia, PA 19104, USA.
authors.forename: F Brad
authors.initials: FB
authors.lastname: Johnson
authors.affiliation: The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA; Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: skorda@wistar.org.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Skordalakes
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D018797:Cell Cycle Proteins / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004271:DNA, Fungal / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism; D059505:Telomere Homeostasis; D034501:Telomere-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: C452219:Cdc13 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; C428109:Stn1 protein, S cerevisiae; D034501:Telomere-Binding Proteins