SPECIAL ISSUE: Muscle: molecules to motion
Summary: The sarcomeric cytoskeleton is a system of proteins specific to striated muscle that play a key role in organising the contractile machinery, and integrating and regulating its mechanics and signalling functions.
Summary: This review summarizes the current knowledge regarding static stiffness, from its identification by our group, to the present, and evaluates the role of titin as the structure possibly responsible for this non-crossbridge stiffness.
MECHANISMS OF MUSCLE CONTRACTION AND EXCITATION-CONTRACTION COUPLING
Effects of hypertrophic and dilated cardiomyopathy mutations on power output by human β-cardiac myosin
Summary: The underlying molecular basis of genetic-based cardiomyopathy diseases is largely unknown. This review describes recent molecular studies that have used human cardiac proteins to begin to elucidate the mechanisms whereby mutations cause disease.
Summary: Mammals express more than 11 different muscle myosin isoforms. Studies of different isoforms and the effect of mutations in these isoforms illustrate how myosin is adapted for specific functions.
Bridging the myoplasmic gap II: more recent advances in skeletal muscle excitation–contraction coupling
Summary: This article reviews recent work regarding the communication between the L-type Ca2+ channel (CaV1.1) and the type 1 ryanodine receptor (RyR1) that supports excitation–contraction coupling in skeletal muscle.
Summary: The mechanics and energetics of muscles doing work (shortening) are better understood than those of muscles being stretched while active. Recent evidence suggests the elastic titin filament plays a key role.
Summary: This review suggests novel mechanisms for muscle eccentric contraction based on interactions among myosin, actin and titin.
Summary: Skeletal muscle adaptation to exercise training serves to blunt the homeostatic intracellular perturbations caused by accelerated energetic demands, and these responses are influenced by exogenous and endogenous energy availability.
Summary: Despite massive reductions in activity and nutrient intake during winter, hibernators largely preserve skeletal muscle. My review summarizes these data and explores potential mechanisms explaining this remarkable outcome.
Summary: New evidence indicates that during hypertrophy, pre-existing muscle fibres recruit nuclei from satellite cells, which are not lost during atrophy. The new permanent myonuclei represent cellular memory facilitating subsequent growth.
METABOLISM AND TISSUE CROSS-TALK
Summary: This review focuses on three steps in oxidative phosphorylation that have independent roles in setting the overall mitochondrial ATP flux and thereby have direct impacts on exercise performance.
Summary: Recent measurements of in vivo substrate kinetics, metabolite transporters and membrane properties greatly improve the understanding of metabolic fuel utilization in fish muscle.
Summary: Taken together, there is a great body of evidence suggesting that novel therapeutics to treat obesity and T2D can be developed by targeting gp130 ligands.
MUSCLE IN MOTION
Summary: Muscles are full of springs. Some roles for elastic elements are well established; others can be predicted based on the potential for energy storage within individual elastic elements.
Summary: This review explains the contribution of early renaissance studies on human anatomy and physiology to our current understanding of the contractile behaviour and adaptations of skeletal muscle to overloading, unloading and ageing.
Summary: The in vivo dynamics of muscle contractile function reflect the interplay of muscle–tendon architecture and neural activation timing relative to the forces and work that muscles produce to power locomotor movement.