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Contractility, cell motility, movement of organelles and vesicles through the cytoplasm, cytokinesis, intracellular cytoplasmic structure, cell polarity, and a variety of other functions are all controlled by the cytoskeleton. It fulfils these duties using three basic structures: actin-based microfilaments with a diameter of 7 to 8 nm, 10-nm IFs with cell-specific composition, and tubulin dimer-based microtubules with a diameter of 24 nm. The cytoskeleton is a dynamic structure in which proteins control the length, state of polymerization, and level of cross-linking of the three primary filaments and tubules.
Cytoskeleton
The cytoskeleton is a system of fibrillar fibres that diffuses the cytoplasm in cell biology. As a result, it might be defined as the component of the cytoplasm that supplies the internal supporting structure for a cell.
The cytoskeleton is a network of filaments and tubules that runs throughout a cell, through the cytoplasm (the whole of the cell’s contents except the nucleus). It can be found in all cells, albeit the proteins that make it up differ from one organism to the next. The cytoskeleton provides support for the cell, shapes organelles, organises and teeters them, and aids chemical transport, cell division, and cell signalling.
Cytoskeleton Structure
Microtubules, microfilaments, and intermediate filaments are the three types of fibres that make up the cytoskeleton. Microtubules are the thickest and microfilaments are the thinnest of these fibres, with microtubules being the thickest.
Microtubules are hollow rods that help maintain and build the cell by acting as “routes” for organelles to move along. Microtubules can be present in every eukaryotic cell. They are roughly 25 nm (nanometres) in diameter and vary in length.
Microfilaments, also known as actin filaments, are small solid rods that assist muscles in contracting. Muscle cells have a high concentration of microfilaments. They are found in all eukaryotic cells, just like microtubules. Microfilaments have a diameter of up to 8 nm and are mostly made up of the contractile protein actin. They also help organelles move around.
Intermediate filaments are numerous in many cells and hold microfilaments and microtubules in place by providing support. Keratins in epithelial cells and neurofilaments in neurons are made up of these filaments. They have a diameter of 10 nm.
Motor Proteins
The cytoskeleton contains several motor proteins. These proteins aggressively move cytoskeleton filaments, as their name implies. Molecules and organelles are therefore moved throughout the cell. The energy source for motor proteins is ATP, which is produced during cellular respiration. In cell movement, there are three types of motor proteins.
Kinesins are proteins that move along microtubules, carrying biological components with them. They’re commonly utilised to attract organelles to the cell membrane.
Dyneins, like kinesins, are proteins that pull cellular components toward the nucleus. As seen in the movement of cilia and flagella, dyneins also function to slide microtubules relative to one another.
To perform muscular contractions, myosins engage with actin. They play a role in cytokinesis, endocytosis, and exocytosis as well.
Function of cytoskeleton
The cytoskeleton is a structure that runs throughout the cytoplasm of a cell and controls a variety of processes.
It aids in the maintenance of the cell’s shape and provides support.
A variety of cellular organelles are held in place by the cytoskeleton.
It aids in the development of vacuoles.
The cytoskeleton is a dynamic structure that can deconstruct and reassemble its components to allow for internal and overall cell mobility. Transport of vesicles into and out of a cell, chromosome manipulation during mitosis and meiosis, and organelle migration are all examples of intracellular movement assisted by the cytoskeleton.
Cell motility is required for tissue building and repair, cytokinesis (cytoplasm division) in the creation of daughter cells, and immune cell responses to pathogens, hence the cytoskeleton facilitates cell movement.
By carrying messages between cells, the cytoskeleton aids cell communication.
In some cells, it creates cellular appendage-like protrusions such as cilia and flagella.
Conclusion
Prokaryotic cytoskeletons are highly dynamic protein systems whose core components are automotive filaments, which are found in some form in all kingdoms of life. The cytoskeleton of the last common ancestor of all living cells, including the ‘simplest’ bacterium, was already very advanced, according to new research. These filaments’ features were so well fitted for an intracellular movement that they were retained throughout evolution. However, because the recruitment of different interacting proteins alters the behaviour of the conserved filaments, The increasingly extensive and readily visible cytoskeletons of eukaryotes are the result of an expansion in the variety of regulatory factors and motor proteins.
