7kpi

Crystal structure of the SPOP MATH domain

spinqualitylabelsall models 7kpi, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7kpi is a 1 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: SPOP (HUMAN) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Speckle-type POZ protein (SPOP) is a ubiquitin ligase adaptor that binds substrate proteins and facilitates their proteasomal degradation. Most SPOP substrates present multiple SPOP-binding motifs and undergo liquid-liquid phase separation with SPOP. Pancreatic and duodenal homeobox 1 (Pdx1), an insulin transcription factor, is downregulated by interaction with SPOP. Unlike other substrates, however, Pdx1 was reported to have just one SPOP-binding (SB) motif within its C-terminal disordered region (Pdx1-C). Given this difference, we aimed to determine the specific mode of interaction of Pdx1 with SPOP and how it is similar or different to that of other SPOP substrates. Here, we identify a second SPOP-binding motif in Pdx1-C, but still find that the resulting moderate valency is insufficient to support phase separation with SPOP in cells. While Pdx1 does not phase separate with SPOP, Pdx1 and SPOP interaction prompts SPOP re-localization from nuclear speckles to the diffuse nucleoplasm. Accordingly, we find that SPOP-mediated ubiquitination activity of Pdx1 occurs in the nucleoplasm and that highly efficient Pdx1 turnover requires both SB motifs. Our results suggest that the subnuclear localization of SPOP-substrate interactions and substrate ubiquitination may be directed by the properties of the substrate itself. Intrinsically disordered substrates dictate SPOP subnuclear localization and ubiquitination activity.,Usher ET, Sabri N, Rohac R, Boal AK, Mittag T, Showalter SA J Biol Chem. 2021 Apr 21:100693. doi: 10.1016/j.jbc.2021.100693. PMID:33894201 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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