Dominant myosin storage myopathy mutations disrupt striated muscles in Drosophila and the myosin tail-tail interactome of human cardiac thick filaments.

Myosin storage myopathy (MSM) is a rare skeletal muscle disorder caused by mutations in the slow muscle/β-cardiac myosin heavy chain (MHC) gene. MSM missense mutations frequently disrupt the tail's stabilizing heptad repeat motif. Disease hallmarks include subsarcolemmal hyaline-like β-MHC aggregates, muscle weakness, and, occasionally, cardiomyopathy.

Cryo-EM structure of the human cardiac myosin filament.

Pumping of the heart is powered by filaments of the motor protein myosin that pull on actin filaments to generate cardiac contraction. In addition to myosin, the filaments contain cardiac myosin-binding protein C (cMyBP-C), which modulates contractility in response to physiological stimuli, and titin, which functions as a scaffold for filament assembly. Myosin, cMyBP-C and titin are all subject to mutation, which can lead to heart failure.

Increasingly negative tropical water-interannual CO growth rate coupling.

Terrestrial ecosystems have taken up about 32% of the total anthropogenic CO emissions in the past six decades. Large uncertainties in terrestrial carbon-climate feedbacks, however, make it difficult to predict how the land carbon sink will respond to future climate change. Interannual variations in the atmospheric CO growth rate (CGR) are dominated by land-atmosphere carbon fluxes in the tropics, providing an opportunity to explore land carbon-climate interactions.

Cryo-EM structure of the human cardiac myosin filament.

Pumping of the heart is powered by filaments of the motor protein myosin, which pull on actin filaments to generate cardiac contraction. In addition to myosin, the filaments contain cardiac myosin-binding protein C (cMyBP-C), which modulates contractility in response to physiological stimuli, and titin, which functions as a scaffold for filament assembly . Myosin, cMyBP-C and titin are all subject to mutation, which can lead to heart failure.

Variants of the myosin interacting-heads motif.

Under relaxing conditions, the two heads of myosin II interact with each other and with the proximal part (S2) of the myosin tail, establishing the interacting-heads motif (IHM), found in myosin molecules and thick filaments of muscle and nonmuscle cells. The IHM is normally thought of as a single, unique structure, but there are several variants. In the simplest ("canonical") IHM, occurring in most relaxed thick filaments and in heavy meromyosin, the interacting heads bend back and interact with S2, and the motif lies parallel to the filament surface.