Go to JCI Insight
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact
  • Clinical Research and Public Health
  • Current issue
  • Past issues
  • By specialty
    • COVID-19
    • Cardiology
    • Gastroenterology
    • Immunology
    • Metabolism
    • Nephrology
    • Neuroscience
    • Oncology
    • Pulmonology
    • Vascular biology
    • All ...
  • Videos
    • Conversations with Giants in Medicine
    • Video Abstracts
  • Reviews
    • View all reviews ...
    • Complement Biology and Therapeutics (May 2025)
    • Evolving insights into MASLD and MASH pathogenesis and treatment (Apr 2025)
    • Microbiome in Health and Disease (Feb 2025)
    • Substance Use Disorders (Oct 2024)
    • Clonal Hematopoiesis (Oct 2024)
    • Sex Differences in Medicine (Sep 2024)
    • Vascular Malformations (Apr 2024)
    • View all review series ...
  • Viewpoint
  • Collections
    • In-Press Preview
    • Clinical Research and Public Health
    • Research Letters
    • Letters to the Editor
    • Editorials
    • Commentaries
    • Editor's notes
    • Reviews
    • Viewpoints
    • 100th anniversary
    • Top read articles

  • Current issue
  • Past issues
  • Specialties
  • Reviews
  • Review series
  • Conversations with Giants in Medicine
  • Video Abstracts
  • In-Press Preview
  • Clinical Research and Public Health
  • Research Letters
  • Letters to the Editor
  • Editorials
  • Commentaries
  • Editor's notes
  • Reviews
  • Viewpoints
  • 100th anniversary
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact
Atrogin-1/muscle atrophy F-box inhibits calcineurin-dependent cardiac hypertrophy by participating in an SCF ubiquitin ligase complex
Hui-Hua Li, … , Da-Zhi Wang, Cam Patterson
Hui-Hua Li, … , Da-Zhi Wang, Cam Patterson
Published October 15, 2004
Citation Information: J Clin Invest. 2004;114(8):1058-1071. https://doi.org/10.1172/JCI22220.
View: Text | PDF
Article Cardiology

Atrogin-1/muscle atrophy F-box inhibits calcineurin-dependent cardiac hypertrophy by participating in an SCF ubiquitin ligase complex

  • Text
  • PDF
Abstract

Calcineurin, which binds to the Z-disc in cardiomyocytes via α-actinin, promotes cardiac hypertrophy in response to numerous pathologic stimuli. However, the endogenous mechanisms regulating calcineurin activity in cardiac muscle are not well understood. We demonstrate that a muscle-specific F-box protein called atrogin-1, or muscle atrophy F-box, directly interacts with calcineurin A and α-actinin-2 at the Z-disc of cardiomyocytes. Atrogin-1 associates with Skp1, Cul1, and Roc1 to assemble an SCFatrogin-1 complex with ubiquitin ligase activity. Expression of atrogin-1 decreases levels of calcineurin A and promotes its ubiquitination. Moreover, atrogin-1 attenuates agonist-induced calcineurin activity and represses calcineurin-dependent transactivation and NFATc4 translocation. Conversely, downregulation of atrogin-1 using adenoviral small interfering RNA (siRNA) expression enhances agonist-induced calcineurin activity and cardiomyocyte hypertrophy. Consistent with these cellular observations, overexpression of atrogin-1 in hearts of transgenic mice reduces calcineurin protein levels and blunts cardiac hypertrophy after banding of the thoracic aorta. These studies indicate that the SCFatrogin-1 ubiquitin ligase complex interacts with and represses calcineurin by targeting calcineurin for ubiquitin-mediated proteolysis, leading to inhibition of cardiac hypertrophy in response to pathologic stimuli.

Authors

Hui-Hua Li, Vishram Kedar, Chunlian Zhang, Holly McDonough, Ranjana Arya, Da-Zhi Wang, Cam Patterson

×

Figure 1

Options: View larger image (or click on image) Download as PowerPoint
Molecular interaction of atrogin-1 with α-actinin-2 and calcineurin A (C...
Molecular interaction of atrogin-1 with α-actinin-2 and calcineurin A (CnA). (A) Yeast 2-hybrid analysis of atrogin-1 interaction with α-actinin-2 (left) and calcineurin A (right). pGBKT7 and pACT2 are empty plasmids. pGAD-T7 vector expresses a T antigen–GAL4 activation domain fusion that interacts with p53 (positive control reaction). (B) In vitro interactions of atrogin-1 with α-actinin-2 and calcineurin A in GST pull-down assays. The ability of α-actinin-2 (top) or calcineurin A (bottom) expressed in COS-7 cells to be retained by GST or a GST–atrogin-1 fusion protein was analyzed by immunoblotting after binding reactions. (C) COS-7 cells were transfected with Xpress-tagged (Xp) atrogin-1 and GFP-tagged calcineurin A or HA-tagged α-actinin-2 expression plasmids as indicated. Equal amounts of cell extract were immunoprecipitated with the Xpress antibody and analyzed by immunoblotting with antibodies directed against Xpress (to detect atrogin-1) and HA (to detect α-actinin-2, top) or against GFP (to detect calcineurin A, bottom). WCE, whole cell extract. (D) Endogenous protein interactions were examined in cardiomyocyte cell lysates that were immunoprecipitated with preimmune serum or anti–atrogin-1 antibody and analyzed by immunoblotting with antibodies to detect α-actinin (top), calcineurin A (middle), and atrogin-1 (bottom). (E) Direct protein interactions were detected by incubation of GST–atrogin-1 or GST (1 μg) with 1 μg of recombinant calcineurin A or α-actinin-2 proteins. Mixtures were precipitated with anti-GST antibody and analyzed by immunoblotting with antibodies against α-actinin, calcineurin A, and GST. (F) Coimmunostaining analysis of endogenous atrogin-1, calcineurin A, and α-actinin-2 in neonatal cardiomyocytes. The overlay shows that atrogin-1 colocalizes with both α-actinin (top) and calcineurin A (middle).

Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)

Sign up for email alerts