Effect of chronic electrostimulation of rabbit skeletal muscle on calmodulin level and protein kinase activity.
(a) Chronic electrostimulation of fast-twitch skeletal muscles makes them resemble slow-twitch muscles. The involvement of second-messenger cascades in this muscle reprogramming is not well understood. The goal of this study was to examine protein kinase activities and calmodulin levels as a function of the duration of electrostimulation. (b) Fast-twitch rabbit muscle was subjected to continuous low-frequency electrostimulation for 2 weeks. The extensor digitorum longus was taken and examined for calmodulin concentration and cAMP-dependent (PKA). Ca(2+)-phospholipid-dependent (PKC) and Ca(2+)-calmodulin-dependent (CaM kinase or PKB) protein kinase activities. (c) Electrostimulation for 14 days led to a significant increase in total calmodulin level and PKB activity, both rising in the cytosolic fraction. Protein kinase C translocated to the membrane fraction, although total activity did not change. (d) These changes could be related with electrostimulation-induced changes in excitation-contraction coupling.
Antipenko
A
A
Departament de Ciències Fisiològiques I, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, Spain.
Frías
J A
JA
Parra
J
J
Cadefau
J A
JA
Cussó
R
R
D000818:Animals; D002147:Calmodulin / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004558:Electric Stimulation; D005260:Female; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011817:Rabbits
D002147:Calmodulin; D011518:Proto-Oncogene Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C