Microtubules vs Intermediate Filaments
Summary: Difference Between Microtubules and Intermediate Filaments is that Microtubules are the straight, hollow and tubular structures of the cytoskeleton. While Intermediate filaments are the structures that form a network around the nucleus and extend to the periphery of the cell.
Microtubules are the straight, hollow and tubular structures of the cytoskeleton. These organelles without the limiting membrane are arranged in different bundles. Each tubule has a diameter of 20 to 30 nm. Length of microtubule varies and it may be 1000 times more than the thickness. Structurally, the microtubules are formed by bundles of globular protein called tubulin. Tubulin has two subunits, namely αsubunit and βsubunit.
Functions of microtubules
- Microtubules may function alone or join with other proteins to form more complex structures like cilia, flagella or centrioles and perform various functions. Microtubules:
- Determine the shape of the cell
- Give structural strength to the cell
- Act like conveyer belts which allow the movement of granules, vesicles, protein molecules and some organelles like mitochondria to different parts of the cell
- Form the spindle fibers which separate the chromosomes during mitosis
- Are responsible for the movement of centrioles and the complex cellular structures like cilia.
Intermediate filaments are the structures that form a network around the nucleus and extend to the periphery of the cell. Diameter of each filament is about 10 nm. The intermediate filaments are formed by ropelike polymers, which are made up of fibrous proteins.
Subclasses of intermediate filaments
Intermediate filaments are divided into five subclasses:
- Keratins (in epithelial cells)
- Glial filaments (in astrocytes)
- Neurofilaments (in nerve cells)
- Vimentin (in many types of cells)
- Desmin (in muscle fibers).
Functions of intermediate filaments
Intermediate filaments help to maintain the shape of the cell. These filaments also connect the adjacent cells through desmosomes.