[Properties of C protein from skeletal and cardiac muscles of the ground squirrel Citellus undulatus at various stages of hibernation].
Changes in the molecular weight and functional properties of the C and X proteins from skeletal muscles and the C protein from the cardiac muscle of hibernating ground squirrels Citellus undulatus at different stages of the hibernation were studied. A decrease in the molecular weight of the C protein from fast fibers of skeletal muscles of hibernating ground squirrels compared with awakening and active animals was revealed. The appearance of shorter molecules of the C protein upon hibernation was accompanied by a lowering of its capacity to enhance the actin-activated ATPase activity of control myosin and by the inhibition of its Ca(2+)-sensitivity. No similar changes were observed for the skeletal X protein and the cardiac C protein. The influence of the skeletal C protein on the main functional properties of myosin allows one to draw a conclusion about its contribution to the inhibition of contractile activity of skeletal muscles upon hibernation. The physiological significance of the changes in the C protein upon hibernation is discussed in connection with similar changes in some cardiomyopathies.
Vikhliantsev
I M
IM
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Alekseeva
Iu A
IuA
Shpagina
M D
MD
Udal'tsov
S N
SN
Podlubnaia
Z A
ZA
D000205:Actomyosin / Q000737:chemistry; D000251:Adenosine Triphosphatases / Q000737:chemistry; D000818:Animals; D002118:Calcium / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D006605:Hibernation; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000737:chemistry*; D009206:Myocardium / Q000737:chemistry*; D012589:Sciuridae / Q000502:physiology*
D002352:Carrier Proteins; C020723:citrate-binding transport protein; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D002118:Calcium