Comparative Biomechanics of Thick Filaments and Thin Filaments with Functional Consequences for Muscle Contraction

Abstract

The scaffold of striated muscle is predominantly comprised of myosin and actin polymers known as thick filaments and thin filaments, respectively. The roles these filaments play in muscle contraction are well known, but the extent to which variations in filament mechanical properties influence muscle function is not fully understood. Here we review information on the material properties of thick filaments, thin filaments, and their primary constituents; we also discuss ways in which mechanical properties of filaments impact muscle performance.

Myopathy-inducing mutation H40Y in ACTA1 hampers actin filament structure and function

“…Simulations tend to suggest that actin filament compliance or extensibility modulates the formation of the myosin cross-bridges and force production [25] , [26] , [27] . Indeed, actin filaments slightly change their helical symmetry and reach their most untwisted and longest length when activated [27] , [28] .…”

“…Indeed, actin filaments slightly change their helical symmetry and reach their most untwisted and longest length when activated [27] , [28] . When extended, F-actin expands the axial range for myosin heads to find target zones along the actin filaments, and as a consequence, provides more binding sites for myosin molecules when compared with rigid actin filaments [26] . ( Fig.…”

Flightin maintains myofilament lattice organization required for optimal flight power and courtship song quality inDrosophila

“…Additionally, the reduction in fibre elastic modulus and the propensity of fln DN62 sarcomeres to tear and thick filaments to buckle under rigour conditions are further manifestations of thick filaments with compromised mechanics. In summary, the results presented here, together with the study of Gasek et al [28], illustrate how filament compliance scales up and influences bulk properties of muscle and animal locomotory performance (reviewed in [29]). This study also shows that the N-terminal domain of flightin is essential for myofilament lattice regularity and proper spacing between thick filaments (d 1,0 ).…”

“…B 284: 20170431 phylogenies, the differences are even greater [23]. It seems appropriate, then, that the N-terminal domain reflects lower conservation given its contributing role to thick filament stiffness, as persistence length is known to range broadly among thick filaments from different muscle types [29].…”

Myocardial Contractility: Historical and Contemporary Considerations

“…Understanding the significance and varied uses of terms that describe cardiac function requires familiarity with the methods and limitations inherent in conducting in vitro and in vivo muscle experiments and their translation to clinical practice (Hinken and Solaro, 2007;Silverman, 2007;Sivaramakrishnan et al, 2009;Miller et al, 2010;Milani-Nejad and Janssen, 2014;Ortega et al, 2015;Sequeira and van der Velden, 2015;Spinale, 2015;Sung et al, 2015;MacLeod, 2016;Noble, 2017;Sweeney and Hammers, 2018;Sweeney and Holzbaur, 2018). Muscle contraction enables animals to move and hollow organs with one-way valves, like the heart, to generate force and transfer blood from veins to arteries.…”