Journal article
Inhibiting Myosin-ATPase Reveals Dynamic Range of Mitochondrial Respiratory Control in Skeletal Muscle
Biochemical journal, Vol.437(2), pp.215-222
07/15/2011
DOI: 10.1042/BJ20110366
PMCID: PMC3863643
PMID: 21554250
Abstract
Assessment of mitochondrial ADP-stimulated respiratory kinetics in permeabilized skeletal myofibres (PmFB) is increasingly used in clinical diagnostic and basic research settings. However, estimates of the Km for ADP vary considerably (∼20-300 μM) and tend to overestimate respiration at rest. Noting PmFBs spontaneously contract during respiration experiments, we systematically determined the impact of contraction, temperature and oxygenation on ADP-stimulated respiratory kinetics. Blebbistatin (BLEB), a myosin II ATPase inhibitor, blocked contraction under all conditions and yielded high Km values for ADP of >∼250 and ∼80 μM in red and white rat PmFB, respectively. In the absence of BLEB, PmFB contracted and the Km for ADP decreased by ∼2 to 10-fold in a temperature-dependent manner. PmFB were sensitive to hyperoxia (increased Km) in the absence of BLEB (contracted) at 30°C but not 37°C. In PmFB from humans, contraction elicited high sensitivity to ADP (m <100 μM) whereas blocking contraction (+BLEB) and including PCr:Cr = 2 to mimic the resting energetic state yielded a Km for ADP = ∼1560 μM, consistent with estimates of
in vivo
resting respiratory rates of <1% maximum. These results demonstrate the sensitivity of muscle to ADP varies over a wide range in relation to contractile state and cellular energy charge, providing evidence that enzymatic coupling of energy transfer within skeletal muscle becomes more efficient in the working state.
Details
- Title: Subtitle
- Inhibiting Myosin-ATPase Reveals Dynamic Range of Mitochondrial Respiratory Control in Skeletal Muscle
- Creators
- Christopher G.R Perry - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Daniel A Kane - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Chien-Te Lin - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Rachel Kozy - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Brook L Cathey - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Daniel S Lark - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Constance L Kane - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Patricia M Brophy - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Timothy P Gavin - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858Ethan J Anderson - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858P. Darrell Neufer - East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA, 27858
- Resource Type
- Journal article
- Publication Details
- Biochemical journal, Vol.437(2), pp.215-222
- DOI
- 10.1042/BJ20110366
- PMID
- 21554250
- PMCID
- PMC3863643
- NLM abbreviation
- Biochem J
- ISSN
- 0264-6021
- eISSN
- 1470-8728
- Grant note
- R01 DK073488 || DK / National Institute of Diabetes and Digestive and Kidney Diseases : NIDDK R01 DK074825 || DK / National Institute of Diabetes and Digestive and Kidney Diseases : NIDDK
- Language
- English
- Date published
- 07/15/2011
- Academic Unit
- Pharmaceutical Sciences and Experimental Therapeutics; Fraternal Order of Eagles Diabetes Research Center; Health, Sport, and Human Physiology
- Record Identifier
- 9984065693402771
Metrics
21 Record Views