Oxygen-regulated degradation of fission yeast SREBP by Ofd1, a prolyl hydroxylase family member

Bridget T. Hughes, Peter J. Espenshade

Research output: Contribution to journalArticlepeer-review


Sre1, the fission yeast sterol regulatory element binding protein, is an endoplasmic reticulum membrane-bound transcription factor that responds to changes in oxygen-dependent sterol synthesis as an indirect measure of oxygen availability. Under low oxygen, Sre1 is proteolytically cleaved and the released N-terminal transcription factor (Sre1N) activates gene expression essential for hypoxic growth. Here, we describe an oxygen-dependent mechanism for regulation of Sre1 that is independent of sterol-regulated proteolysis. Using yeast expressing only Sre1N, we show that Sre1N turnover is regulated by oxygen. Ofd1, an uncharacterized prolyl 4-hydroxylase-like 2-oxoglutarate-Fe(II) dioxygenase, accelerates Sre1N degradation in the presence of oxygen. However, unlike the prolyl 4-hydroxylases that regulate mammalian hypoxia-inducible factor, Ofd1 uses multiple domains to regulate Sre1N degradation by oxygen; the Ofd1 N-terminal dioxygenase domain is required for oxygen sensing and the Ofd1 C-terminal domain accelerates Sre1N degradation. Our data support a model whereby the Ofd1 N-terminal dioxygenase domain is an oxygen sensor that regulates the activity of the C-terminal degradation domain.

Original languageEnglish (US)
Pages (from-to)1491-1501
Number of pages11
JournalEMBO Journal
Issue number10
StatePublished - May 21 2008


  • Degradation
  • Hydroxylase
  • Oxygen
  • Yeast

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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