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. Involved in the tip growth of root hair cells. Plays a major role in trafficking of Golgi stacks, mitochondria and peroxisomes during root hair development. Targets the peroxisome through an interaction with RABC2A. Required for development of pavement cells, trichomes, and stigmatic papillae. Homodimer (By similarity). Interacts with RABC2A AND RABD1. Colocalizes with peroxisome and cytoplasmic vesicles. A number of isoforms are produced. According to EST sequences. Expressed in flowers, leaves, roots and stems. Head-neck domain associates with cytoplasmic (transvacuolar) F-actin in areas coinciding with the tracks of fast organelles. IQ domain mediates interaction with calmodulin. The tail domain is a globular cargo-binding domain. Impaired growth of root hair cells (PubMed:18178669). No visible phenotype (PubMed:15792961). Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family. Plant myosin class XI subfamily.