[Role of atrial myosin light chains in modulating the functional properties of myocardium].
To elucidate the functional importance of the appearance of atrial myosin light chains (ALC) in ventricles in some cardiomyopathies, a partial (75%) substitution of myosin light chains 1 and 2 of the left ventricle for ALC-1 and ALC-2 was carried out in vitro. It is shown that this substitution does not lead to changes in shapes and sizes of the filaments formed by hybrid myosin but causes changes in the shape of myosin heads. The replacement of the light chains increases the actin-activated ATPase activity of hybrid myosin by 63%. The results obtained are evidence that the substitution of ventricle myosin light chains with atrial ones is of physiological importance for the improvement of myosin functional properties and thereby for the compensation of the insufficiency of myocardium in dilated cardiomyopathy. These data and the data on dynamics of ALC-1 in diseased ventricles are important for creating the prognostic test of dilated cardiomyopathy development based on the registration of changes in the isoform composition of cardiac myosin light chains.
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Ia N
IaN
Khalina
M D
MD
Shpagina
S L
SL
Malyshev
Z A
ZA
Podlubnaia
D000199:Actins / Q000502:physiology; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D016275:Atrial Function; D002417:Cattle; D006325:Heart Atria / Q000201:enzymology*; D009218:Myosins / Q000502:physiology*
D000199:Actins; D000251:Adenosine Triphosphatases; D009218:Myosins