title: Structures of SPOP-substrate complexes: insights into molecular architectures of BTB-Cul3 ubiquitin ligases.
abstract: In the largest E3 ligase subfamily, Cul3 binds a BTB domain, and an associated protein-interaction domain such as MATH recruits substrates for ubiquitination. Here, we present biochemical and structural analyses of the MATH-BTB protein, SPOP. We define a SPOP-binding consensus (SBC) and determine structures revealing recognition of SBCs from the phosphatase Puc, the transcriptional regulator Ci, and the chromatin component MacroH2A. We identify a dimeric SPOP-Cul3 assembly involving a conserved helical structure C-terminal of BTB domains, which we call "3-box" due to its facilitating Cul3 binding and its resemblance to F-/SOCS-boxes in other cullin-based E3s. Structural flexibility between the substrate-binding MATH and Cul3-binding BTB/3-box domains potentially allows a SPOP dimer to engage multiple SBCs found within a single substrate, such as Puc. These studies provide a molecular understanding of how MATH-BTB proteins recruit substrates to Cul3 and how their dimerization and conformational variability may facilitate avid interactions with diverse substrates.
authors.affiliation: Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Zhuang
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Calabrese
authors.forename: Jiang
authors.initials: J
authors.lastname: Liu
authors.forename: M Brett
authors.initials: MB
authors.lastname: Waddell
authors.forename: Amanda
authors.initials: A
authors.lastname: Nourse
authors.forename: Michal
authors.initials: M
authors.lastname: Hammel
authors.forename: Darcie J
authors.initials: DJ
authors.lastname: Miller
authors.forename: Helen
authors.initials: H
authors.lastname: Walden
authors.forename: David M
authors.initials: DM
authors.lastname: Duda
authors.forename: Steven N
authors.initials: SN
authors.lastname: Seyedin
authors.forename: Timothy
authors.initials: T
authors.lastname: Hoggard
authors.forename: J Wade
authors.initials: JW
authors.lastname: Harper
authors.forename: Kevin P
authors.initials: KP
authors.lastname: White
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Schulman
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D056970:Co-Repressor Proteins; D016384:Consensus Sequence / Q000502:physiology; D018360:Crystallography, X-Ray; D044842:Cullin Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D018832:Molecular Chaperones; D009154:Mutation / Q000502:physiology; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D054730:Protein Interaction Domains and Motifs / Q000502:physiology; D055503:Protein Multimerization / Q000502:physiology; D020836:Protein Structure, Quaternary / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C503645:CUL3 protein, human; D056970:Co-Repressor Proteins; D044842:Cullin Proteins; C106985:DAXX protein, human; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D006657:Histones; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C509761:SPOP protein, human; D014157:Transcription Factors; C092937:ci protein, Drosophila; C120756:macroH2A histone; D044767:Ubiquitin-Protein Ligases; C110854:puc protein, Drosophila; D010749:Phosphoprotein Phosphatases