JP2 and JCN Crosstalk Abrogate MURF1-Mediated JCN Ubiquitination and Degradation in Cardiomyocytes

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Updated: Apr 20, 2026

Visualization of Cell Cycle Variations and Determination of Nucleation in Postnatal Cardiomyocytes
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Visualization of Cell Cycle Variations and Determination of Nucleation in Postnatal Cardiomyocytes

Published on: February 24, 2017

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Xiaoyun Ji1, Yifan Huang2, Jinxi Wang3

  • 1Northern Jiangsu Cardiovascular Disease Prevention and Treatment Research Institute, Jiangsu University, Zhenjiang, China; Department of Cardiovascular Medicine, Yancheng Third People's Hospital, Yancheng, China; International Genome Center, Jiangsu University, Zhenjiang, China; London Health Sciences Centre Research Institute, London, Ontario, Canada; Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.

JACC. Basic to Translational Science
|April 18, 2026
PubMed

Insights

Junctophilin-2 (JP2) protein protects junctin (JCN) from degradation, preserving heart function. Overexpressing JP2 or inhibiting MURF1 protein can prevent heart failure by maintaining JCN levels and calcium homeostasis.

Area of Science:

  • Cardiovascular Biology
  • Molecular Cardiology
  • Heart Failure Pathophysiology

Background:

  • Junctophilin-2 (JP2) and junctin (JCN) are crucial for calcium homeostasis in cardiomyocytes.
  • Reduced levels of JP2 and JCN are observed in diseased hearts, with JP2 overexpression showing potential to mitigate heart failure.

Purpose of the Study:

  • To investigate the role of JP2 and JCN in cardiomyocyte stress response.
  • To elucidate the molecular mechanism by which JP2 influences JCN stability.
  • To evaluate the therapeutic potential of targeting the JP2-JCN axis in heart disease models.

Main Methods:

  • Assessment of JP2 and JCN levels in stressed cardiomyocytes.
  • Co-immunoprecipitation assays to determine protein interactions (JP2-JCN, MURF1-JCN).
  • In vivo studies using preclinical animal models of cardiomyopathy and heart failure.

Main Results:

  • JP2 and JCN levels decrease in cardiomyocytes under stress, leading to calcium dysregulation and cell death.
  • JP2 directly binds to JCN, inhibiting the interaction with muscle ring finger protein-1 (MURF1).
  • This inhibition prevents MURF1-mediated ubiquitination and degradation of JCN.
  • JP2 overexpression or MURF1 inhibition preserved JCN protein, attenuated cardiac injury, and improved cardiac function in disease models.

Conclusions:

  • The JP2-JCN axis is vital for maintaining JCN protein stability and cardiomyocyte function.
  • Disruption of this axis is a key mechanism in heart disease development.
  • Targeting the JP2-JCN interaction offers a potential therapeutic strategy for cardiac protection.

Keywords:
MURF1cardiomyocytejunctinjunctophilin-2ubiquitination

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