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Updated: May 24, 2026
Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols
Published on: June 6, 2017
CHFR protein regulates mitotic checkpoint by targeting PARP-1 protein for ubiquitination and degradation
Lisa Kashima1, Masashi Idogawa, Hiroaki Mita
1Department of Medical Genome Sciences, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo 060-8556, Japan.
Abstract:
The mitotic checkpoint gene CHFR (checkpoint with forkhead-associated (FHA) and RING finger domains) is silenced by promoter hypermethylation or mutated in various human cancers, suggesting that CHFR is an important tumor suppressor. Recent studies have reported that CHFR functions as an E3 ubiquitin ligase, resulting in the degradation of target proteins. To better understand how CHFR suppresses cell cycle progression and tumorigenesis, we sought to identify CHFR-interacting proteins using affinity purification combined with mass spectrometry. Here we show poly(ADP-ribose) polymerase 1 (PARP-1) to be a novel CHFR-interacting protein. In CHFR-expressing cells, mitotic stress induced the autoPARylation of PARP-1, resulting in an enhanced interaction between CHFR and PARP-1 and an increase in the polyubiquitination/degradation of PARP-1. The decrease in PARP-1 protein levels promoted cell cycle arrest at prophase, supporting that the cells expressing CHFR were resistant to microtubule inhibitors. In contrast, in CHFR-silenced cells, polyubiquitination was not induced in response to mitotic stress. Thus, PARP-1 protein levels did not decrease, and cells progressed into mitosis under mitotic stress, suggesting that CHFR-silenced cancer cells were sensitized to microtubule inhibitors. Furthermore, we found that cells from Chfr knockout mice and CHFR-silenced primary gastric cancer tissues expressed higher levels of PARP-1 protein, strongly supporting our data that the interaction between CHFR and PARP-1 plays an important role in cell cycle regulation and cancer therapeutic strategies. On the basis of our studies, we demonstrate a significant advantage for use of combinational chemotherapy with PARP inhibitors for cancer cells resistant to microtubule inhibitors.
Insights
The checkpoint with forkhead-associated (FHA) and RING finger domains) gene (CHFR) suppresses tumors by degrading PARP-1. Loss of CHFR increases PARP-1, impacting cell cycle and cancer therapy strategies.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Biology
Background:
- The CHFR gene acts as a tumor suppressor, often silenced or mutated in human cancers.
- CHFR functions as an E3 ubiquitin ligase, targeting proteins for degradation.
- Understanding CHFR's role in cell cycle regulation and tumorigenesis is crucial for cancer therapy.
Purpose of the Study:
- To identify proteins interacting with CHFR.
- To elucidate the mechanism by which CHFR suppresses cell cycle progression and tumorigenesis.
- To explore the therapeutic implications of the CHFR-interacting protein complex.
Main Methods:
- Affinity purification coupled with mass spectrometry to identify CHFR-interacting proteins.
- Analysis of CHFR and PARP-1 interactions under mitotic stress.
- Assessment of polyubiquitination and protein degradation levels.
- Comparison of Chfr knockout mouse cells and CHFR-silenced gastric cancer tissues.
Main Results:
- Poly(ADP-ribose) polymerase 1 (PARP-1) was identified as a novel CHFR-interacting protein.
- Mitotic stress induced autoPARylation of PARP-1, enhancing CHFR-PARP-1 interaction and promoting PARP-1 polyubiquitination and degradation.
- CHFR-mediated PARP-1 degradation led to prophase cell cycle arrest, conferring resistance to microtubule inhibitors.
- CHFR-silenced cells showed increased PARP-1 levels and sensitivity to microtubule inhibitors.
- Elevated PARP-1 levels were observed in Chfr knockout mouse cells and CHFR-silenced gastric cancer tissues.
Conclusions:
- The interaction between CHFR and PARP-1 is critical for cell cycle regulation.
- CHFR-mediated degradation of PARP-1 plays a significant role in tumor suppression.
- Targeting the CHFR-PARP-1 pathway offers potential therapeutic strategies for cancer.
- Combination therapy with PARP inhibitors may benefit cancer cells resistant to microtubule inhibitors.
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