Structures of SPOP-substrate complexes: insights into molecular architectures of BTB-Cul3 ubiquitin ligases.
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.
Zhuang
Min
M
Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
Calabrese
Matthew F
MF
Liu
Jiang
J
Waddell
M Brett
MB
Nourse
Amanda
A
Hammel
Michal
M
Miller
Darcie J
DJ
Walden
Helen
H
Duda
David M
DM
Seyedin
Steven N
SN
Hoggard
Timothy
T
Harper
J Wade
JW
White
Kevin P
KP
Schulman
Brenda A
BA
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
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