The properties of the actin-myosin interaction in the heart muscle depend on the isoforms of myosin but not of α-actin.
In myocardium of mammals there are two isoforms of myosin heavy chains, α and β. In ventricle, together with ventricular isoforms of light chains they form two isomyosins: V1 and V3, homodimers of α- and β-heavy chains, respectively. In atria, α- and β-heavy chains together with atrial light chains form A1 (αα) and A2 (ββ) isomyosins. Besides in myocardium two isoforms of α-actin, skeletal and cardiac, are expressed. We assume that the differences in the amino acid sequence of cardiac and skeletal actin may affect its interaction with myosin. To test this hypothesis, we investigated characteristics of actin-myosin interactions of cardiac and skeletal isoforms of α-actin with the isoforms of cardiac myosin using an optical trap technique and an in vitro motility assay. It was found that the mechanical and kinetic characteristics of the interactions of the isoforms of cardiac myosin with actin depend on the isoforms of myosin not α-actin.
Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia. Electronic address: g_rodionova@mail.ru.
G
G
Kopylova
Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia.
S
S
Nabiev
Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia.
L
L
Nikitina
Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia.
D
D
Shchepkin
Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia.
S
S
Bershitsky
D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D066298:In Vitro Techniques; D007700:Kinetics; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D009206:Myocardium / Q000737:chemistry* / Q000378:metabolism; D009218:Myosins / Q000737:chemistry* / Q000378:metabolism; D052898:Optical Tweezers; D054730:Protein Interaction Domains and Motifs; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D011817:Rabbits
D000199:Actins; D020033:Protein Isoforms; D009218:Myosins
Actin isoforms; Actin-myosin interaction; Cardiac myosin isoforms; In vitro motility assay; Optical trap