Effects of cardiac myosin binding protein-C on the regulation of interaction of cardiac myosin with thin filament in an in vitro motility assay.
Modulatory role of whole cardiac myosin binding protein-C (сMyBP-C) in regulation of cardiac muscle contractility was studied in the in vitro motility assay with rabbit cardiac myosin as a motor protein. The effects of cMyBP-C on the interaction of cardiac myosin with regulated thin filament were tested in both in vitro motility and ATPase assays. We demonstrate that the addition of cMyBP-C increases calcium regulated Mg-ATPase activity of cardiac myosin at submaximal calcium. The Hill coefficient for 'pCa-velocity' relation in the in vitro motility assay decreased and the calcium sensitivity increased when сMyBP-C was added. Results of our experiments testifies in favor of the hypothesis that сMyBP-C slows down cross-bridge kinetics when binding to actin.
Shchepkin
D V
DV
Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg 620041, Russia. d.shchepkin@iip.uran.ru
Kopylova
G V
GV
Nikitina
L V
LV
Katsnelson
L B
LB
Bershitsky
S Y
SY
D008841:Actin Cytoskeleton / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001681:Biological Assay; D002118:Calcium / Q000378:metabolism; D024722:Cardiac Myosins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism; D009200:Myocardial Contraction; D011817:Rabbits; D000099163:Myosin Binding Protein C
D000251:Adenosine Triphosphatases; D002118:Calcium; D024722:Cardiac Myosins; D002352:Carrier Proteins; D008274:Magnesium; D000099163:Myosin Binding Protein C