Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Regulates Rho by stimulating it's GTPase activity in neurons. Required for the regulation of neurite branching and motor neuron axon guidance (PubMed:27259756). Localized in the cytoplasm of cell bodies, dendrites and axons with occasional hints of an enrichment near the plasma membrane. Localized at the neuromuscular junction (PubMed:27259756). Expressed in the eye, lung, liver, brain, heart, kidney, skeletal muscle and spleen. No detection was found in liver. In the brain, expressed in the ependymal cells of the third ventricle and the aqueduct (PubMed:19828736). Detected in whole embryos at 7, 11, 15 and 17 dpc. Also present in limb buds from 13.5 dpc. At 16.5 dpc, it is expressed throughout the developing nervous system, eye, inner ear, kidney, thyroid gland and teeth. Phosphorylated by ALPK1 following monosodium urate monohydrate (MSU)-induced inflammation. Knockout mice display retarded growth, a dome-shaped skull, and develop severe hydrocephalus with stenosis and closure of the ventral caudal third ventricle and the aqueduct. Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family. Represents an unconventional myosin. This protein should not be confused with the conventional myosin-9 (MYH9).