Abstract
Myosin XI is a plant-specific class of myosin motor. It is thought that unidirectional actin filament bundles and organelle-associated myosin XI cause bulk flow in the cell. We demonstrated that the myosin XI-K is associated with ER and acts as the primary contributor to the ER streaming in Arabidopsis. Double- and triple-myosin xik mutants showed not only the suppression of the ER movement but also the abnormally spatial configuration of the ER. Interestingly, this configuration resembled ER configuration in the wild-type cells treated with an actin-depolymerizing reagent. We found that the myosin XI deficiency affects the orientation of the actin filament bundles. Our data suggests that myosin XI-K in cooperation with the other myosin XI is involved in organizing actin filament bundles. We will discuss about the involvement of the ER streaming in the organization of the actin filament bundles.
