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Method for Measuring the Activity of Deubiquitinating Enzymes in Cell Lines and Tissue Samples
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The deubiquitinase USP9X regulates RIT1 protein abundance and oncogenic phenotypes

Amanda K Riley1,2, Michael Grant3, Aidan Snell3

  • 1Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.

Biorxiv : the Preprint Server for Biology
|December 11, 2023
PubMed

Insights

The deubiquitinase USP9X regulates RIT1 protein levels in lung cancer. USP9X depletion reduces RIT1 abundance, resensitizing cells to EGFR inhibitors.

Area of Science:

  • Oncology
  • Molecular Biology
  • Biochemistry

Background:

  • RIT1 is an understudied oncogene in lung cancer.
  • RIT1 activity is regulated by protein abundance, not nucleotide exchange.
  • USP9X was previously identified as a RIT1 dependency in RIT1-mutant cells.

Approach:

  • Investigated the relationship between USP9X and both wild-type and mutant RIT1 forms.
  • Assessed the impact of USP9X depletion on RIT1 protein stability and abundance.
  • Examined the effect of USP9X modulation on cellular sensitivity to EGFR tyrosine kinase inhibitors.

Key Points:

  • Both wild-type and mutant RIT1 proteins are substrates of the deubiquitinase USP9X.
  • Depletion of USP9X results in reduced RIT1 protein stability and lower overall RIT1 levels.
  • Reducing USP9X levels resensitizes RIT1-driven lung cancer cells to EGFR tyrosine kinase inhibitors.

Conclusions:

  • USP9X is a key regulator of RIT1 protein abundance and stability.
  • USP9X plays a critical role in RIT1-driven oncogenic phenotypes in lung cancer.
  • Targeting USP9X may represent a therapeutic strategy for RIT1-mutant lung cancers.

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