Cytoplasmic Streaming Enables the Distribution of Molecules and Vesicles in Large Plant Cells

Recent studies of aquatic and land plants show that similar phenomena determine intracellular transport of organelles and vesicles. This suggests that aspects of cell signaling involved in development and response to external stimuli are conserved across species. The movement of molecular motors along cytoskeletal filaments directly or indirectly entrains the fluid cytosol, driving cyclosis (i.e., cytoplasmic streaming) and affecting gradients of molecular species within the cell, with potentially important metabolic implications as a driving force for cell expansion. Research has shown that myosin XI functions in organelle movement driving cytoplasmic streaming in aquatic and land plants. Despite the conserved cytoskeletal machinery propelling organelle movement among aquatic and land plants, the velocities of cyclosis in plant cells varies according to cell types, developmental stage of the cell, and plant species. Here, we synthesize recent insights into cytoplasmic streaming, molecular gradients, cytoskeletal and membrane dynamics, and expand current cellular models to identify important gaps in current research.