Controlled hydrolysis of nucleotides and inorganic phosphate release by motor proteins can generate mechanical forces that can be used for:
* Translocating the motor proteins themselves along the filaments
* stabilizing and/or moving the filaments (i.e., contractile stress fibers) & escorting cargo that is attached to the motor protein (e.g., vesicles, organelles, other proteins) to specific regions in the cell
* In most cases, motor proteins transport substances in a particular direction, or polarity, along the filaments. This directionality is achieved by specific conformational changes that allow movement in only one direction.
Myosin I has unique tail domain(s) relative to other myosin members which allows myosin I to bind to membrane lipids or to more than one actin filament at a time (see panel 'A' in Figure below). Myosin I is primarily involved in intracellular organization, but it also forms a critical component of small cell surface projections in intestinal cells.
Myosin V and Myosin VI In non-muscle cells, actin filaments form an internal track system for cargo transport that is powered by motor proteins such as myosin V and VI ( see panel 'C' in Figure below); these myosins use the energy from ATP hydrolysis to transport cargo (such as attached vesicles and organelles) at rates much faster than diffusion. Myosin V contains more light chains and a longer 'lever arm' relative to myosin II, which allows myosin V to move in larger steps along the actin filaments (reviewed in ).
Myosin V may also colocalize with F-actin bundles. The distribution of myosin V in growth cones is consistent with the role for this myosin in tension production by growth cones. Myosin V may influence the filopodial extension rate by pushing the plasma membrane and creating space for G-actin subunit assembly onto the barbed ends of actin filaments[9, 10]
Myosin VII and Myosin X are important for filopodial assembly and dynamics [11, 12]. Myosin VII is believed to influence the assembly/disassembly of adhesion proteins at the filopodial tip  as well as play a role in filopodial extension events. Myosin X activity also influences the filopodia number and overall length with calmodulin-like protein (CLP) modulating this activity by stabilizing myosin X . Myosin X influences transport of materials along filopodial shafts using an ATP-dependent ‘walking’ mechanism. Myosin X binds cell surface receptors, cytoskeleton, Ena/VASP proteins, and membrane phospholipids [11, 14, 15, 16]. Myosin X also has a striking distribution at the tips of filopodia and disrupting its function disrupts filopodium formation [17, 18].