Myofilaments: Movers and Rulers of the Sarcomere.
Striated cardiac and skeletal muscles play very different roles in the body, but they are similar at the molecular level. In particular, contraction, regardless of the type of muscle, is a precise and complex process involving the integral protein myofilaments and their associated regulatory components. The smallest functional unit of muscle contraction is the sarcomere. Within the sarcomere can be found a sophisticated ensemble of proteins associated with the thick filaments (myosin, myosin binding protein-C, titin, and obscurin) and thin myofilaments (actin, troponin, tropomyosin, nebulin, and nebulette). These parallel thick and thin filaments slide across one another, pulling the two ends of the sarcomere together to regulate contraction. More specifically, the regulation of both timing and force of contraction is accomplished through an intricate network of intra- and interfilament interactions belonging to each myofilament. This review introduces the sarcomere proteins involved in striated muscle contraction and places greater emphasis on the more recently identified and less well-characterized myofilaments: cardiac myosin binding protein-C, titin, nebulin, and obscurin. © 2017 American Physiological Society. Compr Physiol 7:675-692, 2017.
Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.
Brian Leei
BL
Lin
Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.|Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
Taejeong
T
Song
Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.|Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
Sakthivel
S
Sadayappan
D064211:Connectin / Q000502:physiology; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology; D009124:Muscle Proteins / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D009210:Myofibrils / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases; D064067:Rho Guanine Nucleotide Exchange Factors / Q000502:physiology; D012518:Sarcomeres / Q000502:physiology*; D014336:Troponin / Q000502:physiology
D064211:Connectin; D009124:Muscle Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; D014336:Troponin; C035620:nebulin; C578224:OBSCN protein, human; D017346:Protein Serine-Threonine Kinases