Non-muscle myosin heavy chain IIB (MYH10) (NMHC-IIB or NMIIB)

Non-muscle myosin heavy chain IIB (NMIIB) is a molecular motor protein that generates intracellular mechanical force and motion on actin filaments. Encoded by the MYH10 gene located on chromosome 17, it functions as a 228.9 kDa protein composed of two heavy chains and four light chains organized into a hexameric complex. The protein contains an N-terminal globular head with catalytic magnesium-ATPase activity for motor function and a C-terminal coiled-coil rod domain that enables multimerization into filaments. NMIIB plays essential roles in cell motility, adhesion, division, and the maintenance of cellular structures including stress fibers and adherens junctions. This isoform displays distinct kinetic properties compared to other myosin II isoforms, including slower ATPase cycling and higher ADP affinity, resulting in prolonged strong actin binding and cross-linking functions. NMIIB is particularly critical for cardiac muscle development, intercalated disc integrity, and proper E-cadherin-mediated cell-cell adhesion. Mutations in MYH10 have been associated with disease phenotypes, and dysregulation of NMIIB assembly and function through phosphorylation can profoundly alter cellular metabolism, gene expression, and morphology.

Other names

Myosin heavy chain 10MYH10Non-muscle myosin II heavy chain BNM-IIB

NMIIB generates mechanical force through ATP hydrolysis via its catalytic motor domain, which binds filamentous actin. The protein functions as a hexamer composed of two heavy chains and four light chains. Regulation occurs through phosphorylation of the regulatory light chain (MLC20) and heavy chain phosphorylation, which modulates filament assembly and disassembly. NMIIB displays slower ATPase kinetics and higher ADP affinity compared to other myosin II isoforms, resulting in prolonged strong actin binding.