Hui-Hua Li, Vishram Kedar, Chunlian Zhang, Holly McDonough, Ranjana Arya, Da-Zhi Wang, Cam Patterson
J Clin Invest.
2004;
114(8):1058–1071
doi:10.1172/JCI22220
This article Copyright © 2004, The American Society for Clinical Investigation
Abstract
|
Full text
|
PDF
C
alcineurin, 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.
This file is in Adobe Acrobat (PDF) format.
If you have not installed and configured the Adobe Acrobat Reader on your system.
Having trouble reading a PDF?
PDFs are designed to be printed out and read, but if you prefer to read them online, you may find it easier if you increase the view size to 125%.
Having trouble saving a PDF?
Many versions of the free Acrobat Reader do not
allow Save. You must instead save the PDF from the JCI Online page you downloaded it from. PC users:
Right-click on the Download link and choose the option that says something like "Save Link As...".
Mac users should hold the mouse button down on the link to get these same options.
Having trouble printing a PDF?
- Try printing one page at a time or to a newer printer.
- Try saving the file to disk before printing rather than opening it "on the fly." This requires that you
configure your browser to "Save" rather than "Launch Application" for the file type "application/pdf", and can
usually be done in the "Helper Applications" options.
- Make sure you are using the latest version of Adobe's Acrobat Reader.