title: Molecular assembly of the period-cryptochrome circadian transcriptional repressor complex.
abstract: The mammalian circadian clock is driven by a transcriptional-translational feedback loop, which produces robust 24-hr rhythms. Proper oscillation of the clock depends on the complex formation and periodic turnover of the Period and Cryptochrome proteins, which together inhibit their own transcriptional activator complex, CLOCK-BMAL1. We determined the crystal structure of the CRY-binding domain (CBD) of PER2 in complex with CRY2 at 2.8 Å resolution. PER2-CBD adopts a highly extended conformation, embracing CRY2 with a sinuous binding mode. Its N-terminal end tucks into CRY adjacent to a large pocket critical for CLOCK-BMAL1 binding, while its C-terminal half flanks the CRY2 C-terminal helix and sterically hinders the recognition of CRY2 by the FBXL3 ubiquitin ligase. Unexpectedly, a strictly conserved intermolecular zinc finger, whose integrity is important for clock rhythmicity, further stabilizes the complex. Our structure-guided analyses show that these interspersed CRY-interacting regions represent multiple functional modules of PERs at the CRY-binding interface.
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, United States.
authors.forename: Shannon N
authors.initials: SN
authors.lastname: Nangle
authors.affiliation: Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States.
authors.forename: Clark
authors.initials: C
authors.lastname: Rosensweig
authors.affiliation: Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Nobuya
authors.initials: N
authors.lastname: Koike
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Ishikawa, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Tei
authors.affiliation: Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States joseph.takahashi@utsouthwestern.edu.
authors.forename: Joseph S
authors.identifier: http://orcid.org/0000-0003-0384-8878
authors.initials: JS
authors.lastname: Takahashi
authors.affiliation: Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States carla.green@utsouthwestern.edu.
authors.forename: Carla B
authors.initials: CB
authors.lastname: Green
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, United States Howard Hughes Medical Institute, University of Washington, Seattle, United States nzheng@u.washington.edu.
authors.forename: Ning
authors.initials: N
authors.lastname: Zheng
mesh_terms: D056930:ARNTL Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D057906:Circadian Clocks / Q000235:genetics*; D056931:Cryptochromes / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018360:Crystallography, X-Ray; D044783:F-Box Proteins / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D056950:Period Circadian Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D056930:ARNTL Transcription Factors; C538961:Bmal1 protein, mouse; C538967:Cry2 protein, mouse; D056931:Cryptochromes; D044783:F-Box Proteins; C519794:Fbxl3 protein, mouse; D046912:Multiprotein Complexes; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins
keywords: circadian rhythm; cryptochrome; period