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Regulation of p27 (Kip1) by Ubiquitin E3 Ligase RNF6

Dhanraj Deshmukh1, Jin Xu1, Xi Yang1

  • 1Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.

Pharmaceutics
|April 23, 2022
PubMed

Insights

Ring Finger Protein 6 (RNF6) promotes cell cycle progression by degrading the cyclin-dependent kinase inhibitor p27 (Kip1) in prostate cancer cells. Inhibiting RNF6 increases p27 stability, arresting cells in G1 phase.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • p27 (Kip1) is a key regulator of the G1/S cell cycle checkpoint.
  • Degradation of p27 by SCF-SKP2 complex facilitates cell cycle progression.
  • The role of E3 ubiquitin ligase RNF6 in prostate cancer cell cycle regulation is unexplored.

Purpose of the Study:

  • To investigate the role of RNF6 in regulating cell cycle progression in prostate cancer.
  • To determine the mechanism by which RNF6 affects p27 levels and stability.
  • To elucidate the impact of RNF6 on cell proliferation.

Main Methods:

  • Knockdown of RNF6 using short hairpin RNA (shRNA).
  • Analysis of p27 protein levels and stability.
  • Assessment of cell cycle phase distribution (G1 arrest).
  • Investigation of RNF6-p27 interaction and ubiquitination.
  • Evaluation of CDK2/Cyclin E complex activity and Rb phosphorylation.

Main Results:

  • RNF6 promotes cell cycle progression by reducing p27 levels.
  • RNF6 knockdown increases p27 stability and causes G1 phase arrest.
  • RNF6 interacts with p27 via its KIL domain in a phosphorylation-independent manner.
  • RNF6 enhances p27 ubiquitination and proteasomal degradation in early G0/G1.
  • RNF6 knockdown inhibits CDK2/Cyclin E, reduces Rb phosphorylation, and decreases proliferation.

Conclusions:

  • RNF6 acts as a negative regulator of p27 (Kip1).
  • RNF6 facilitates proteasome-dependent degradation of p27 in early G0/G1.
  • RNF6 plays a significant role in prostate cancer cell cycle progression and proliferation.
Keywords:
RNF6cell cyclep27prostate cancer

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