Gueguen 2005 J Physiol: Difference between revisions
No edit summary |
Bader Helga (talk | contribs) No edit summary |
||
Line 1: | Line 1: | ||
{{Publication | {{Publication | ||
|title=Gueguen N, Lefaucheur L, Ecolan P, Fillaut M, Herpin P (2005) Ca2+-activated myosin-ATPases, creatine and adenylate kinases regulate mitochondrial function according to myofibre type in rabbit. J Physiol 564: 723- | |title=Gueguen N, Lefaucheur L, Ecolan P, Fillaut M, Herpin P (2005) Ca2+-activated myosin-ATPases, creatine and adenylate kinases regulate mitochondrial function according to myofibre type in rabbit. J Physiol 564:723-35. | ||
|info=[http://www.ncbi.nlm.nih.gov/pubmed/15731190 PMID: 15731190] | |info=[http://www.ncbi.nlm.nih.gov/pubmed/15731190 PMID: 15731190] | ||
|authors=Gueguen N, Lefaucheur L, Ecolan P, Fillaut M, Herpin P | |authors=Gueguen N, Lefaucheur L, Ecolan P, Fillaut M, Herpin P | ||
Line 11: | Line 11: | ||
}} | }} | ||
{{Labeling | {{Labeling | ||
|organism=Rabbit | |organism=Rabbit | ||
|tissues=Skeletal muscle | |tissues=Skeletal muscle | ||
|preparations=Permeabilized tissue, Enzyme | |preparations=Permeabilized tissue, Enzyme | ||
|topics=Substrate;glucose;TCA cycle | |||
|couplingstates=OXPHOS | |couplingstates=OXPHOS | ||
| | |instruments=Oxygraph-2k | ||
|discipline=Mitochondrial Physiology | |discipline=Mitochondrial Physiology | ||
}} | }} |
Revision as of 10:14, 25 February 2015
Gueguen N, Lefaucheur L, Ecolan P, Fillaut M, Herpin P (2005) Ca2+-activated myosin-ATPases, creatine and adenylate kinases regulate mitochondrial function according to myofibre type in rabbit. J Physiol 564:723-35. |
Gueguen N, Lefaucheur L, Ecolan P, Fillaut M, Herpin P (2005) J Physiol
Abstract: Mitochondrial respiration rates and their regulation by ADP, AMP and creatine, were studied at different free Ca2+ concentrations (0.1 versus 0.4 ฮผm) on permeabilized fibre bundles of rabbit skeletal muscles differing in their myosin heavy chain profiles. Four fibre bundle types were obtained: pure types I and IIx, and mixed types IIax (approximately 50% IIa and 50% IIx fibres) and IIb+ (60% IIb fibres, plus IIx and IIa). At rest, pure type I fibres displayed a much higher apparent Km for ADP (212 ฮผm) than IIx fibres (8 ฮผm). Within the IIax and IIb+ mixed fibre bundle types, two KADPm values were observed (70 ฮผm and 5 ฮผm). Comparison between pure IIx and mixed types indicates that the intermediate Km of 70 ฮผm most probably corresponds to the mitochondrial affinity for ADP in IIa fibres, the lowest Km for ADP (5 ฮผm) corresponding to IIx and IIb types. Activation of mitochondrial creatine and adenylate kinase reactions stimulated mitochondrial respiration only in type I and IIax fibre bundles, indicating an efficient coupling between both kinases and ADP rephosphorylation in type I and, likely, IIa fibres, since no effect was observed in pure IIx fibres. Following Ca2+ -induced activation of myosin-ATPase, an increase in mitochondrial sensitivity to ADP of 45% and 250% was observed in type IIax and I bundles, respectively, an effect mostly prevented by addition of vanadate, an inhibitor of myosin-ATPase. Ca2+ -induced activation of myosin-ATPase also prevented the stimulation of respiration rates by creatine and AMP in I and IIax bundles. In addition to differential regulation of mitochondrial respiration and energy transfer systems at rest in I and IIa versus IIx and IIb muscle fibres, our results indicate a regulation of phosphotransfer systems by Ca2+ via the stimulation of myosin-ATPases in type I and IIa fibres of rabbit muscles. โข Keywords: Rabbit
โข O2k-Network Lab: FR_Saint Gilles_Lefaucheur L, FR_Angers_Douay O
Labels:
Organism: Rabbit
Tissue;cell: Skeletal muscle
Preparation: Permeabilized tissue, Enzyme
Regulation: Substrate;glucose;TCA cycle"Substrate;glucose;TCA cycle" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property. Coupling state: OXPHOS
HRR: Oxygraph-2k