cytoskeletonfunction

The cytoskeleton is a dynamic network of protein filaments that provides structure and organization to most eukaryotic cells. It consists mainly of microfilaments (actin filaments), intermediate filaments, and microtubules. Together, these elements determine cell shape, mechanical properties, and the organization and movement of organelles and vesicles within the cytoplasm.

Actin filaments support cell motility, endocytosis, and cytokinesis, and contribute to the formation of cellular protrusions such as lamellipodia and filopodia. Microtubules organize intracellular transport, position organelles, and form the mitotic spindle during cell division. Intermediate filaments provide tensile strength and help maintain cellular integrity. The network also mediates connections to membranes and extracellular contacts.

Filaments are dynamic, continually assembling and disassembling. Microtubules undergo dynamic instability, while actin filaments undergo rapid remodeling and treadmilling. Nucleation and elongation are guided by specialized proteins and complexes (for microtubules, gamma-tubulin ring complexes; for actin, Arp2/3 and formins). Motor proteins—kinesins and dyneins move along microtubules, and myosins move along actin—driving cargo transport and force generation.

Disruption of cytoskeleton dynamics can contribute to disease, including cancer cell invasion, neurodegenerative disorders, and inherited filament defects. Because of its central role in cell biology, the cytoskeleton is a major focus of research and therapeutic strategies aimed at modifying cell shape, division, and intracellular transport.