The cytoskeleton is a protein-based internal framework present in cells that performs three principal functions: providing structural support, enabling movement, and mediating intracellular transport of substances. In animal cells it comprises three filament classes distinguished by composition and diameter — microtubules (~25 nm), which form the mitotic spindle, constitute cilia and flagella, and serve as tracks for intracellular transport; intermediate filaments (~10 nm), which resist mechanical stress and maintain cell shape elastically; and microfilaments (~7 nm), which drive whole-cell movement and shape change from within, as in cytokinetic furrowing and pseudopod extension. The concept belongs to cell biology and is the structural counterpart to organelle physiology, supplying the mechanical and organizational scaffold within which other cellular processes occur.
The cytoskeleton is a protein-based internal framework present in cells that performs three principal functions: providing structural support, enabling movement, and mediating intracellular transport…