The multi-subunit GID/CTLH E3 ubiquitin ligase promotes cell proliferation and targets the transcription factor Hbp1 for degradation

Elife. 2018 Jun 18;7:e35528. doi: 10.7554/eLife.35528.


In yeast, the glucose-induced degradation-deficient (GID) E3 ligase selectively degrades superfluous gluconeogenic enzymes. Here, we identified all subunits of the mammalian GID/CTLH complex and provide a comprehensive map of its hierarchical organization and step-wise assembly. Biochemical reconstitution demonstrates that the mammalian complex possesses inherent E3 ubiquitin ligase activity, using Ube2H as its cognate E2. Deletions of multiple GID subunits compromise cell proliferation, and this defect is accompanied by deregulation of critical cell cycle markers such as the retinoblastoma (Rb) tumor suppressor, phospho-Histone H3 and Cyclin A. We identify the negative regulator of pro-proliferative genes Hbp1 as a bonafide GID/CTLH proteolytic substrate. Indeed, Hbp1 accumulates in cells lacking GID/CTLH activity, and Hbp1 physically interacts and is ubiquitinated in vitro by reconstituted GID/CTLH complexes. Our biochemical and cellular analysis thus demonstrates that the GID/CTLH complex prevents cell cycle exit in G1, at least in part by degrading Hbp1.

Keywords: E3 ubiquitin ligase; N-end rule; S. cerevisiae; biochemistry; cell biology; cell proliferation; chemical biology; human; metabolism; mouse; transcription factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Proliferation*
  • Cells, Cultured
  • G1 Phase
  • Gene Expression Regulation
  • HEK293 Cells
  • HeLa Cells
  • High Mobility Group Proteins / genetics
  • High Mobility Group Proteins / metabolism*
  • Humans
  • Mice, Inbred C57BL
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Ubiquitin-Conjugating Enzymes / genetics
  • Ubiquitin-Conjugating Enzymes / metabolism
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*


  • HBP1 protein, human
  • High Mobility Group Proteins
  • Repressor Proteins
  • Transcription Factors
  • UBE2E2 protein, human
  • UBE2H protein, human
  • Ubiquitin-Conjugating Enzymes
  • Ubiquitin-Protein Ligases

Grants and funding

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.