Skeletal muscle myosin II (MyHC) (MyHC)

Skeletal muscle myosin II is a hexameric motor protein that serves as the primary engine for muscle contraction by converting chemical energy from ATP into mechanical work. It is composed of two heavy chains (MyHC) and two pairs of light chains, with the heavy chains containing the ATPase activity and actin-binding sites necessary for the power stroke [1][2]. In humans, different isoforms such as MYH1, MYH2, and MYH4 define the contractile properties of fast-twitch fibers, while MYH7 is predominant in slow-twitch fibers [3]. This target is of significant therapeutic interest for neuromuscular and muscle-wasting diseases, including Amyotrophic Lateral Sclerosis (ALS) and sarcopenia, where increasing the efficiency of remaining muscle fibers can improve patient mobility and respiratory function [4]. Pharmacological modulators like CK-2066260 are designed to specifically activate skeletal myosin to enhance force production without affecting cardiac muscle [5]. Conversely, mutations in these myosin genes are linked to various congenital myopathies and distal arthrogryposis syndromes, highlighting its central role in musculoskeletal health [6].

Other names

Sarcomeric myosinMyosin-2Fast skeletal muscle myosinSlow skeletal muscle myosinMyosin heavy chainMHC

Direct modulation of the myosin ATPase cycle to either increase (activators) or decrease (inhibitors) the rate of force-producing cross-bridge formation between myosin and actin.