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Microtubules are key components of the cytoskeleton in eukaryotic cells, playing critical roles in maintaining cell shape, enabling intracellular transport, and facilitating cell division. They are hollow cylindrical structures composed of polymerized tubulin proteins, specifically α-tubulin and β-tubulin dimers. These dimers assemble into protofilaments, which then arrange into 13 parallel strands to form a microtubule’s characteristic tube-like shape.

Microtubules exhibit dynamic instability, meaning they can rapidly switch between growing and shrinking phases in response to cellular signals. This property is essential for processes like mitosis, where microtubules form the spindle apparatus that segregates chromosomes during cell division. They also serve as tracks for motor proteins such as kinesin and dynein, which transport organelles, vesicles, and other cargo throughout the cell.

In addition to structural support, microtubules are involved in cell motility, particularly in the movement of cilia and flagella, which rely on microtubule-based structures called axonemes. Disruptions in microtubule function, often due to genetic mutations or chemical interference, can lead to diseases such as neurodegenerative disorders, certain cancers, and developmental abnormalities.

The regulation of microtubule assembly and disassembly is tightly controlled by associated proteins, including microtubule-associated proteins (MAPs) and microtubule-stabilizing or destabilizing factors. For example, drugs like taxanes stabilize microtubules, preventing their depolymerization, while other compounds like colchicine inhibit their formation. Research into microtubules continues to provide insights into cellular mechanics, drug development, and fundamental biological processes.