Related Experiment Video
Updated: May 9, 2025

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
F-box protein FBXO32 ubiquitinates and stabilizes D-type cyclins to drive cancer progression
Feng Li1,2,3, Hongqiang Yu1, Yujun Zhang1
1Key Laboratory of Hepatobiliary and Pancreatic Surgery, Institute of Hepatobiliary Surgery, Southwest Hospital, Army Medical University, Chongqing, China.
Abstract:
D-type cyclins (hereafter, cyclin D) are central regulators orchestrating G1/S cell cycle transition. Accordingly, aberrant expression of cyclin D is strongly correlated with proliferation-related diseases such as cancer. However, the mechanisms regulating cyclin D turnover are incompletely elucidated. Here we identify FBXO32, namely atrogin-1, as the E3 ubiquitin ligase that targets all three cyclin D for ubiquitination and stabilization. Specifically, FBXO32 catalyzes the lysine (Lys/K)27-linked polyubiquitination of cyclin D1 at the K58 site and subsequent stabilization. Moreover, GSK-3β inactivation-mediated dephosphorylation of cyclin D1 facilitates its interaction with FBXO32 and subsequent ubiquitination. Furthermore, FBXO32 exhibits tumor-promoting effect in mouse models and increased FBXO32 is associated with poor prognosis of cancer patients. Additionally, disrupting the FBXO32-cyclin D axis enhances the tumor-killing effect of cyclin-dependent kinase (CDK)4/6 inhibitor palbociclib. Collectively, these findings reveal that FBXO32 enhances the protein stability of cyclin D via K27-linked ubiquitination, and contributes to cancer progression and the limited response of cancer cells to CDK4/6 inhibitors.
Related Concept Videos
Anaphase Promoting Complex
Inhibition of Cdk Activity
Positive Regulator Molecules
Negative Regulator Molecules
MAPK Signaling Cascades
M-Cdk Drives Transition Into Mitosis
Cyclin-dependent kinases, or Cdks, work in concert with cyclins to control cell cycle transitions. M-Cdk, a complex of Cdk1 bound to M cyclin, is a well-known example of this coordinated control that drives the transition from the G2 to the M phase.
M cyclin...

