Microtubuledependent

Microtubule-dependent describes cellular processes that require microtubules, the cylindrical polymers composed of tubulin that form a major part of the cytoskeleton. Microtubules provide structural support and create organized networks that act as tracks for molecular motors, enabling directed movement of organelles, vesicles, and protein complexes within eukaryotic cells. They are dynamic, undergoing phases of growth and shrinkage (dynamic instability), which helps regulate transport routes and force generation.

Motor proteins such as kinesin and dynein drive most microtubule-dependent transport. Kinesins usually move cargo toward the microtubule plus ends (often away from the cell center), while dynein moves toward the minus ends (typically toward the center). This system distributes mitochondria, endosomes, lysosomes, synaptic vesicles, and other cargo along microtubule tracks, supporting processes from neuronal signaling to general cell maintenance.

In cell division, microtubule-dependent mechanisms organize the mitotic spindle, align chromosomes, and segregate sister chromatids. Microtubules attach to kinetochores and generate the forces that move chromosomes during metaphase and anaphase, with motor proteins and microtubule dynamics coordinating accurate segregation.

Other contexts of microtubule dependence include intraflagellar transport within cilia and flagella, and long-range axonal transport in neurons. Regulation of microtubule stability and interactions with microtubule-associated proteins (MAPs) modulates motor activity and cargo binding, shaping the efficiency and fidelity of microtubule-dependent processes.

Clinically, defects in microtubule dynamics or motor proteins can contribute to neurodevelopmental and neurodegenerative disorders. Pharmacological agents that stabilize or destabilize microtubules also impact these processes and are used in cancer therapy.