Non-muscle myosin II (NM II)

Non-muscle myosin II is a major cytoskeletal molecular motor protein complex, responsible for ATP-dependent contractile force generation in nearly all eukaryotic cells outside of muscle tissue[3][4][5][6]. Structurally, it is a hexamer composed of two heavy chains (encoded by MYH9/10/14 for isoforms NM IIA/IIB/IIC), two essential light chains, and two regulatory light chains[3][4][5][6]. It dynamically assembles into bipolar filaments that interact with actin filaments to drive processes such as cytokinesis, cell migration, shape change, mechanotransduction, and maintenance of tissue architecture[3][4][5][6][1]. Distinct NM II isoforms (A, B, C) have specialized and overlapping cellular functions, with mutations or dysregulation implicated in numerous diseases including cancer metastasis, cardiovascular disorders, developmental defects, and specific hereditary syndromes[6][1]. NM II activity and assembly are tightly regulated through phosphorylation of regulatory light chains and various signaling pathways[2][5]. Selective inhibition of non-muscle myosin II is under investigation for conditions involving abnormal cell migration, contractility, or division.

Other names

NM IINM2NMIINonmuscle myosin 2Non-muscle myosin heavy chain II (for isoforms: MYH9/NM IIA, MYH10/NM IIB, MYH14/NM IIC)Non-muscle myosin-2 (alternative hyphenation)Non-muscle myosin II heavy chain

Inhibition of myosin II ATPase activity (by blebbistatin and related) Blockade of actomyosin contractility/filament formation