The plant-specific protein motor class myosin XI is known to
function in rapid bulk flow of the cytoplasm (cytoplasmic
streaming) and in organellar movements. Recent studies
unveiled a wide range of physiological functions of myosin XI
motors, from intracellular motility to organ movements.
Arabidopsis thaliana has 13 members of myosin XI class.
In vegetative organs, myosins XIk, XI1, and XI2 primarily
contribute to dynamics and spatial configurations of
endoplasmic reticulum that develops a tubular network in the
cell periphery and thick strand-like structures in the inner cell
regions. Myosin XI-i forms a nucleocytoplasmic linker and is
responsible for nuclear movement and shape. In addition to
these intracellular functions, myosin XIf together with myosin
XIk is involved in the fundamental nature of plants; the actin–
myosin XI cytoskeleton regulates organ straightening to
adjust plant posture.