Cardiac myosin-binding protein C decorates F-actin: implications for cardiac function.
Cardiac myosin-binding protein C (cMyBP-C) is an accessory protein of striated muscle sarcomeres that is vital for maintaining regular heart function. Its 4 N-terminal regulatory domains, C0-C1-m-C2 (C0C2), influence actin and myosin interactions, the basic contractile proteins of muscle. Using neutron contrast variation data, we have determined that C0C2 forms a repeating assembly with filamentous actin, where the C0 and C1 domains of C0C2 attach near the DNase I-binding loop and subdomain 1 of adjacent actin monomers. Direct interactions between the N terminus of cMyBP-C and actin thereby provide a mechanism to modulate the contractile cycle by affecting the regulatory state of the thin filament and its ability to interact with myosin.
Whitten
Andrew E
AE
Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia.
Jeffries
Cy M
CM
Harris
Samantha P
SP
Trewhella
Jill
J
D000199:Actins / Q000502:physiology*; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006334:Heart Function Tests; D051379:Mice; D008958:Models, Molecular; D012542:Scattering, Radiation; D000099163:Myosin Binding Protein C
D000199:Actins; D002352:Carrier Proteins; D000099163:Myosin Binding Protein C