HSP72 Is a Mitochondrial Stress Sensor Critical for Parkin Action, Oxidative Metabolism, and Insulin Sensitivity in Skeletal Muscle
- Brian G. Drew1,
- Vicente Ribas1,
- Jamie A. Le1,
- Darren C. Henstridge2,
- Jennifer Phun1,
- Zhenqi Zhou1,
- Teo Soleymani1,
- Pedram Daraei1,
- Daniel Sitz1,
- Laurent Vergnes3,
- Jonathan Wanagat4,
- Karen Reue3,
- Mark A. Febbraio2 and
- Andrea L. Hevener1⇑
- 1David Geffen School of Medicine, Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, University of California, Los Angeles, Los Angeles, CA
- 2Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
- 3David Geffen School of Medicine, Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA
- 4David Geffen School of Medicine, Department of Medicine, Division of Geriatrics, University of California, Los Angeles, Los Angeles, CA
- Corresponding author: Andrea L. Hevener, .
Increased heat shock protein (HSP) 72 expression in skeletal muscle prevents obesity and glucose intolerance in mice, although the underlying mechanisms of this observation are largely unresolved. Herein we show that HSP72 is a critical regulator of stress-induced mitochondrial triage signaling since Parkin, an E3 ubiquitin ligase known to regulate mitophagy, was unable to ubiquitinate and control its own protein expression or that of its central target mitofusin (Mfn) in the absence of HSP72. In wild-type cells, we show that HSP72 rapidly translocates to depolarized mitochondria prior to Parkin recruitment and immunoprecipitates with both Parkin and Mfn2 only after specific mitochondrial insult. In HSP72 knockout mice, impaired Parkin action was associated with retention of enlarged, dysmorphic mitochondria and paralleled by reduced muscle respiratory capacity, lipid accumulation, and muscle insulin resistance. Reduced oxygen consumption and impaired insulin action were recapitulated in Parkin-null myotubes, confirming a role for the HSP72-Parkin axis in the regulation of muscle insulin sensitivity. These data suggest that strategies to maintain HSP72 may provide therapeutic benefit to enhance mitochondrial quality and insulin action to ameliorate complications associated with metabolic diseases, including type 2 diabetes.
This article contains Supplementary Data online at http://diabetes.diabetesjournals.org/lookup/suppl/doi:10.2337/db13-0665/-/DC1.
- Received April 25, 2013.
- Accepted December 23, 2013.
- © 2014 by the American Diabetes Association.
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