Polarmikrotubuli

Polarmikrotubuli, also known as polar microtubules, are a class of microtubules that originate from the spindle poles of the mitotic spindle and extend towards the spindle equator without reaching the kinetochores of chromosomes. They play a crucial role in cell division by contributing to the elongation of the cell and the separation of the spindle poles during anaphase. These microtubules are dynamic structures, undergoing continuous polymerization and depolymerization, which contributes to their function in establishing and maintaining the spindle architecture.

Unlike kinetochore microtubules, which attach to chromosomes, polarmikrotubuli interact with each other and with astral microtubules (which extend from the spindle pole towards the cell cortex) at the spindle midzone. This interaction helps to push the spindle poles apart, generating the force necessary to elongate the cell and ensure proper segregation of chromosomes into daughter cells. Their assembly and organization are tightly regulated by a complex network of motor proteins and microtubule-associated proteins, ensuring the fidelity of cell division. Disruption of polarmikrotubuli function can lead to aneuploidy and other cellular defects.