<P> Microtubules function as tracks in the intracellular transport of membrane - bound vesicles and organelles, and this process is propelled by motor proteins such as dynein . Microtubules are cytoskeletal fibers that have an important role in the mitotic spindle during mitosis . They are organized in such a way that their plus ends extend through the periphery of the cells and their minus ends are anchored within the centrosome, so they utilize the motor proteins kinesin's (positive end directed) and dynein's (negative end directed) to transport vesicles and organelles in opposite directions through the cytoplasm (cite: the cell a molecular approach). Each type of membrane vesicle is specifically bound to its own kinesin motor protein via binding within the tail domain . One of the major roles of microtubules is to transport membrane vesicles and organelles through the cytoplasm of eukaryotic cells . It is speculated that areas within the cell considered "microtubule - poor" are probably transported along microfilaments aided by a myosin motor protein . Another important role Microtubules play is during mitosis when the cell has undergone a duplication event and is in the process of creating daughter cells . Microtubules make up the mitotic spindle which are responsible for distributing the chromosomes to daughter nuclei during anaphase . During Anaphase there is a shortening event, called Anaphase A, in which the chromosomes move towards the spindle poles by utilizing the dynein motor proteins . </P> <P> By understanding the components and mechanisms of intracellular transport it is possible to see its implication in diseases . Defects encompass improper sorting of cargo into transport carriers, vesicle budding, issues in movement of vesicles along cytoskeletal tracks, and fusion at the target membrane . Since the life cycle of the cell is a highly regulated and important process, if any component goes awry there is the possibility for deleterious effects . If the cell is unable to correctly execute components of the intracellular pathway there is the impending possibility for protein aggregates to form . Growing evidence supports the concept that deficits in axonal transport contributes to pathogenesis in multiple neurodegenerative diseases . It is proposed that protein aggregations due to faulty transport is a leading cause of the development of ALS, Alzheimer's and Dementia . </P> <P> On the other hand, targeting the intracellular transport processes of these motor proteins constitutes the possibility for pharmacological targeting of drugs . By understanding the method in which substances move along neurons or microtubules it is possible to target specific pathways for disease . Currently, many drug companies are aiming to utilize the trajectory of intracellular transport mechanisms to deliver drugs to localized regions and target cells without harming healthy neighboring cells . The potential for this type of treatment in anti-cancer drugs is an exciting, promising area of research . </P>

Which structure in plant cells facilitates intercellular transport