Structural insights into substrate recognition by the SOCS2 E3 ubiquitin ligase

Wei-Wei Kung, Sarath Ramachandran, Nikolai Makukhin, Elvira Bruno, Alessio Ciulli (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)
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The suppressor of cytokine signaling 2 (SOCS2) acts as substrate recognition subunit of a Cullin5 E3 ubiquitin ligase complex. SOCS2 binds to phosphotyrosine-modified epitopes as degrons for ubiquitination and proteasomal degradation, yet the molecular basis of substrate recognition has remained elusive. Here, we report co-crystal structures of SOCS2 ElonginB-ElonginC in complex with phosphorylated peptides from substrates growth hormone receptor (GHR-pY595) and erythropoietin receptor (EpoR-pY426) at 1.98 Å and 2.69 Å, respectively. Both peptides bind in an extended conformation recapitulating the canonical SH2 domain-pY pose, but capture different conformations of the EF loop via specific hydrophobic interactions. The flexible BG loop is fully defined in the electron density, and does not contact the substrate degron directly. Cancer-associated SNPs located around the pY pocket weaken substrate-binding affinity in biophysical assays. Our findings reveal insights into substrate recognition and specificity by SOCS2, and provide a blueprint for small molecule ligand design.
Original languageEnglish
Article number2534
Pages (from-to)1-14
Number of pages14
JournalNature Communications
Issue number1
Publication statusPublished - 10 Jun 2019


  • Crystallography, X-Ray
  • Humans
  • Phosphotyrosine/chemistry
  • Polymorphism, Single Nucleotide
  • Protein Conformation
  • Receptors, Erythropoietin/chemistry
  • Receptors, Somatotropin/chemistry
  • Sequence Alignment
  • Substrate Specificity
  • Suppressor of Cytokine Signaling Proteins/chemistry
  • Ubiquitin-Protein Ligases/chemistry
  • Ubiquitination


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