Let me share with you a comparison between microtubules, microfilaments and intermediate filaments.
| Aspect | Microtubules | Microfilaments | Intermediate Filaments |
| Structure | Long, unbranched, slender tubulin protein structures. | Solid, thin filaments composed of actin protein subunits arranged in a helical structure. | Fibrous proteins composed of various proteins such as keratins, vimentin and lamins. |
| Diameter | 25 nm | 7 nm | 10 nm |
| Polymers | Polymers of α-tubulin and β-tubulin | Polymers of actin monomers (G-actin) | Polymers of various proteins depending on the cell types |
| Function | · Provide structural support,
· Maintain cell shape · Act as tracks for intracellular transport · Forms the mitotic spindle during cell division |
· Involved in cell shape maintenance
· Muscle contraction · Cell motility · cell division · Intracellular transport |
· Provide mechanical strength to cells,
· Anchor organelles, · Helps cells to withstand mechanical stress |
| Motor Proteins | Interact with motor proteins such as dynein and kinesin for intracellular transport | Interact with myosin motor proteins for muscle contraction and intracellular transport | Limited interactions with motor proteins |
| Distribution | Extend throughout the cell, including the cytoplasm and nucleus | Form a network just beneath the cell membrane and are concentrated in the cortex of the cell | Distributed throughout the cell, providing structural support and forming a network in the cytoplasm |
| Associated Structures | Centrosomes contain a pair of centrioles. | Form stress fibers, lamellipodia, and filopodia in the cell cortex. | Integrate with desmosomes and hemidesmosomes. |