3IVQ

Structures of SPOP-Substrate Complexes: Insights into Molecular Architectures of BTB-Cul3 Ubiquitin Ligases: SPOPMATH-CiSBC2

Summary for 3IVQ

• Entry DOI: 10.2210/pdb3ivq/pdb
• Related: 3IVV
• Descriptor: Speckle-type POZ protein, CiSBC2 (3 entities in total)
• Functional Keywords: protein binding, nucleus, ubl conjugation pathway, ligase
• Biological source: Homo sapiens (human)
• Cellular location: Nucleus: O43791
• Total number of polymer chains: 4
• Total formula weight: 35698.68

Authors

Schulman, B.A.,Miller, D.J.,Calabrese, M.F.,Seyedin, S. (deposition date: 2009-09-01, release date: 2009-10-20, Last modification date: 2024-02-21)

Primary citation

Zhuang, M.,Calabrese, M.F.,Liu, J.,Waddell, M.B.,Nourse, A.,Hammel, M.,Miller, D.J.,Walden, H.,Duda, D.M.,Seyedin, S.N.,Hoggard, T.,Harper, J.W.,White, K.P.,Schulman, B.A.
Structures of SPOP-Substrate Complexes: Insights into Molecular Architectures of BTB-Cul3 Ubiquitin Ligases.
Mol.Cell, 36:39-50, 2009

PubMed 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.

PubMed: 19818708
DOI: 10.1016/j.molcel.2009.09.022

Experimental method

X-RAY DIFFRACTION (2.1 Å)