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Structure of Cytoskeleton in Eukaryotic Cells

    In this structure of cytoskeleton in eukaryotic cells post we have briefly explained about cytoskeleton in eukaryotic cells, structure, microfilaments, intermediate filaments, microtubules, and functions.

    The term “cytoskeleton” refers to the cytoplasmic structures that provide mechanical support, shape, and strength to the cell in the same way that the human skeleton does for the human body. Proteins form these structures, which can be very small, fibrous, filamentous, or tubular.

    Definition

    Cytoskeleton in eukaryotic cells is a network of protein fibres in the cytoplasm that acts as a structural framework for the cell, providing stability and assisting in cell movement. It is composed of various proteins such as tubulin, actin, myosin, tropomyosin, keratin, and others.

    It is a flexible or dynamic structure since it has no fixed shape and can change shape depending on the conditions or environment. The cytoskeleton in eukaryotic cells allows internal cellular structures such as the nucleus and cell organelles to maintain their places inside the cell and maintain a safe distance between them.

    Structure of Cytoskeleton in Eukaryotic Cells

    Cytoskeleton

    Structure of Cytoskeleton in Eukaryotic Cells

    Although all cells contain a cytoskeleton, when the term “cytoskeleton” is used, it usually refers to the cytoskeleton in eukaryotic cells. Eukaryotic cells are multicellular organisms that contain a nucleus and organelles. Eukaryotic cells are found in plants, mammals, fungi, and protists.

    Prokaryotic cells are simpler than eukaryotic cells, having no genuine nucleus or organelles other than ribosomes, and are found in bacteria and archaea, which are single-celled creatures. The cytoskeleton of prokaryotic cells was first identified in the early 1990s, when it was considered to be non-existent.

    Microfilaments, intermediate filaments, and microtubules make up the eukaryotic cytoskeleton, which is made up of elongated chains of proteins.

    Microfilaments

    Because they are largely made up of the protein actin, microfilaments are also known as actin filaments; their structure is two strands of actin twisted in a spiral. They’re around 7 nanometers thick, making them the cytoskeleton’s thinnest filaments. Microfilaments serve a variety of purposes.

    They help with cytokinesis, which is the partition of a cell’s cytoplasm into two daughter cells when it divides. They help single-celled creatures like amoebas move by assisting cell motility. They also play a role in cytoplasmic streaming, or the movement of cytosol (the liquid part of the cytoplasm) throughout the cell.

    Nutrients and cell organelles are transported by cytoplasmic streaming. Microfilaments, like myosin, are a component of muscle cells that allow them to contract. The two primary components of muscle contractile elements are actin and myosin.

    Functions

    1. They give the cell its shape and stiffness. During cell division, they aid in the production of spindle filaments.

    2. Cilia and flagella’s cytoskeleton, or internal support framework, is made up of them. They aid in chromosomal separation during the anaphase stage of cell division.

    3. As shown in the paramecium, where cilia made of microtubules help transfer food to the gullet or mouth of the paramecium, microtubules aid in the intracellular transportation of nutrients.

    4. Microtubules are also involved in a variety of cell motions, including intracellular transport and membrane orientation. It also aids the movement of secretory vesicles throughout the cell.

    Intermediate filaments

    Keratin, desmin, nestin, and vimentin are some of the proteins that make them up. Their length is roughly 10 nm, which is longer than the microtubule (25 nm) but shorter than the microfilament (50 nm) (7 nm).

    As a result, they’re known as intermediate filaments. They are exceedingly stable and give the nuclear membrane and anchor cell organelles form and mechanical strength. They do not participate in cell motility, unlike other cytoskeleton components.

    Functions

    1. They offer support for the cell and can be placed in a mesh-like structure to accommodate various cell types. They play a role in chromatin formation.

    2. It gives the structures in which it is found tensile strength. For instance, in hairs. When cells are stretched, they are able to endure mechanical stress. 

    3. As a result, they are more prominent in cells that are subjected to increased mechanical stress. For example, epithelial cells in the skin protect cells from breaking owing to mechanical shear by dispersing the effect of localised stress uniformly.

    Microtubules

    They have no lumen since they are solid, unbranched rod-like structures. They are also known as actin filaments and are found in eukaryotic cells.

    In comparison to other regions of the cytoskeleton, they are relatively thin. Microfilaments are made up of contractile proteins such as actin and myosin, which are both strong and flexible, making them ideal for cell movement. Myosin is a filamentous protein, whereas actin is a globular protein.

    Functions

    1. They operate as scaffolding for the plasma membrane, providing support and assisting in the maintenance of its structure.

    2. Because they are contractile in nature, they aid in movement. By forming a cleavage furrow, they also aid cell division. The heart’s contraction is aided by actin-myosin filaments.

    3. Microfilaments can also be found in microvilli, which are finger-like projections in the cell that enhance the absorption surface area.

    Cytoskeleton Functions

    1. It assists the cell in maintaining its form and provides support. The cytoskeleton keeps a variety of cellular organelles in place. It aids in the development of vacuoles.

    2. The cytoskeleton is a dynamic framework that may deconstruct and rearrange its components to allow for internal and overall cell mobility.

    3. Cell mobility is required for tissue construction and repair, cytokinesis (cytoplasm division) in the generation of daughter cells, and immune cell responses to pathogens, all of which require the cytoskeleton.

    4. The cytoskeleton helps cells communicate by transporting signals between them. In some cells, it creates cellular appendage-like protrusions like cilia and flagella.

    Further Readings

    Reference

    1. https://biologydictionary.net/cytoskeleton/
    2. https://www.biologyonline.com/dictionary/cytoskeleton
    3. https://byjus.com/biology/cytoskeleton/
    4. https://www.thoughtco.com/cytoskeleton-anatomy-373358
    5. https://www.springer.com/gp/chemistry/biochemistry