Deubiquitinating enzyme mutagenesis screens identify a USP43-dependent HIF-1 transcriptional response

EMBO J. 2024 Sep;43(17):3677-3709. doi: 10.1038/s44318-024-00166-6. Epub 2024 Jul 15.

Abstract

The ubiquitination and proteasome-mediated degradation of Hypoxia Inducible Factors (HIFs) is central to metazoan oxygen-sensing, but the involvement of deubiquitinating enzymes (DUBs) in HIF signalling is less clear. Here, using a bespoke DUBs sgRNA library we conduct CRISPR/Cas9 mutagenesis screens to determine how DUBs are involved in HIF signalling. Alongside defining DUBs involved in HIF activation or suppression, we identify USP43 as a DUB required for efficient activation of a HIF response. USP43 is hypoxia regulated and selectively associates with the HIF-1α isoform, and while USP43 does not alter HIF-1α stability, it facilitates HIF-1 nuclear accumulation and binding to its target genes. Mechanistically, USP43 associates with 14-3-3 proteins in a hypoxia and phosphorylation dependent manner to increase the nuclear pool of HIF-1. Together, our results highlight the multifunctionality of DUBs, illustrating that they can provide important signalling functions alongside their catalytic roles.

Keywords: DUB; Deubiquitination; HIF; Hypoxia; USP43.

MeSH terms

  • CRISPR-Cas Systems
  • Deubiquitinating Enzymes* / genetics
  • Deubiquitinating Enzymes* / metabolism
  • HEK293 Cells
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit* / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit* / metabolism
  • Mutagenesis
  • Signal Transduction
  • Ubiquitination

Substances

  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Deubiquitinating Enzymes
  • HIF1A protein, human