May be involved in intracellular trafficking of the muscle cell when in the cytoplasm, whereas entering the nucleus, may be involved in the regulation of muscle specific genes. May play a role in the control of tumor development and progression; restored MYO18B expression in lung cancer cells suppresses anchorage-independent growth. Homodimer. May interact with F actin through the GPA motif (Gly/Pro/Ala-rich). Punctate pattern in undifferentiated myoblasts. Nuclear, on primary cardiomyocytes and adult muscle. A partial sarcomeric location was found in some cardiomyocytes. Selectively expressed in cardiac and skeletal muscles. Weakly expressed in testis, pancreas, placenta, prostate, lung and thymus. Reaches an expression peak in the third day after induction and remains at similar level during successive myotubule maturation. The disease is caused by variants affecting the gene represented in this entry. Frequently deleted, mutated, and hypermethylated in lung cancers. Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family.