cytoskeletets

The cytoskeleton (cytoskeletets) is a dynamic, filamentous network in eukaryotic cells that provides shape and mechanical support, organizes internal structures, and drives movement. It comprises three main types of protein filaments that constantly assemble and disassemble in response to cellular needs, enabling rapid remodeling during processes such as division, migration, and differentiation.

The three filament systems are microfilaments (actin filaments), intermediate filaments, and microtubules. Microfilaments support the cell cortex and generate force for movement via myosin motors; they underlie lamellipodia and filopodia in migrating cells. Intermediate filaments provide tensile strength and structural integrity. Microtubules form rigid tubes that organize the cytoplasm, act as tracks for motor proteins, arrange the mitotic spindle, and support ciliogenesis and vesicle transport.

Motor proteins such as myosin, dynein, and kinesin convert chemical energy into mechanical work to move along these filaments, transporting organelles, vesicles, and chromosomes, and driving muscle contraction in specialized cells. Accessory proteins cross-link and stabilize filaments and regulate their dynamics.

The cytoskeleton interacts with membranes, signaling pathways, and organelles, shaping cell adhesion, polarity, and signaling. Its dynamics are tightly regulated by cellular energy, post-translational modifications, and small GTPases.

Disruption of cytoskeletal components or regulation is linked to diseases such as cancer metastasis, neurodegenerative disorders, and cardiomyopathies. Several drugs target microtubules to interfere with cell division in cancer therapy.