Myosin heavy chain that is required for the cell cycle-regulated transport of various organelles and proteins for their segregation. Functions by binding with its tail domain to receptor proteins on organelles and exerting force with its N-terminal motor domain against actin filaments, thereby transporting its cargo along polarized actin cables. Contributes to the trafficking of Golgi stacks, mitochondria and peroxisomes. Required for development of pavement cells, trichomes, and stigmatic papillae. Homodimer (PubMed:18429938). Interacts with MYOB1 and MYOB2 (PubMed:23995081). Interacts with PHOX1 (PubMed:28096376). Colocalizes with peroxisome, cytoplasmic vesicles and/or organelles. IQ domain mediates interaction with calmodulin. The tail domain is a globular cargo-binding domain. No visible phenotype. Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family. Plant myosin class XI subfamily.