Intermediate Filaments - Definition, Structure, Function  (2023)

FAQs

What is the structure of the intermediate filament? ›

Intermediate filaments are composed of smaller strands in the shape of rods. Eight rods are aligned in a staggered array with another eight rods, and these components all twist together to form the rope-like conformation of an intermediate filament.

Intermediate filaments, in contrast to actin filaments and microtubules, are very stable structures that form the true skeleton of the cell. They anchor the nucleus and position it within the cell, and they give the cell its elastic properties and its ability to withstand tension.

Intermediate filaments (IF) are proteins which are primordial components of the cytoskeleton and the nuclear envelope. They generally form filamentous structures 8 to 14 nm wide and intermediate in size between microtubules and microfilaments.

Intermediate filaments have great tensile strength, and their main function is to enable cells to withstand the mechanical stress that occurs when cells are stretched.

Microfilaments, also called actin filaments, as they consist of two intertwined strands of a globular protein known as actin. They are the polymers of the protein actin and are smallest filaments of the cytoskeleton. They have a vital role in cell movements, cell division, and muscle contraction.

Intermediate filaments (IFs) are a key component of the cytoskeleton in virtually all vertebrate cells, including those of the lens of the eye. IFs help integrate individual cells into their respective tissues.

Intermediate filaments regulate nucleus rigidity

Thus, alterations of nucleus rigidity affect the cell ability to squeeze in between matrix fibers. Lamins are the type IV intermediate filament proteins that are the major components of the nuclear membrane [50] and largely affect the mechanical property of the nucleus.

Epithelia are exposed to multiple forms of stress. Keratin intermediate filaments are abundant in epithelia and form cytoskeletal networks that contribute to cell type–specific functions, such as adhesion, migration, and metabolism. A perpetual keratin filament turnover cycle supports these functions.

Intermediate filaments function primarily as flexible intracellular tendons (analogous to nylon rope) that prevent excessive stretching of cells that are subjected to external or internal physical forces.

The intermediate filaments comprise the major component of the cytoskeleton and consist of five major subgroups—vimentin, keratins, desmin, neurofilaments, and glial fibrillary acidic protein (GFAP)—and a small number of minor subgroups (e.g., nestin, peripherin).

What is the function of filament? ›

The main function that filament performs is to carry nutrients to the anther for the development of the anther and pollen grains.

Intermediate structures means vehicle components to which the partitioning system is attached to the prescribed vehicle(s) which do not constitute the anchorages.

Intermediate filaments have no role in cell movement. Their function is purely structural. They bear tension, thus maintaining the shape of the cell, and anchor the nucleus and other organelles in place.

Key Points

Microfilaments assist with cell movement and are made of a protein called actin. Actin works with another protein called myosin to produce muscle movements, cell division, and cytoplasmic streaming. Microfilaments keep organelles in place within the cell.

Intermediate Filaments Definition. strong polymers of fibrous polypeptides that resist stretch and play a structural (tension-bearing) function, Found in most, but not all cell types.

Microfilaments are composed of two strands of subunits of the protein actin (hence the name actin filaments) wound in a spiral. Specifically, the actin subunits that come together to form a microfilament are called globular actin (G-actin), and once they are joined together they are called filamentous actin (F-actin).

The structure of the microfilaments is double helix. The structure of the microtubules is helical lattice. 2. Microfilaments are composed of the contractile proteins called as actin. Microtubules are composed of the subunits of a protein tubulin.

Microtubules, with intermediate filaments and microfilaments, are the components of the cell skeleton which determinates the shape of a cell. Microtubules are involved in different functions including the assembly of mitotic spindle, in dividing cells, or axon extension, in neurons.

The cytoskeleton is a network of fibers forming the "infrastructure" of eukaryotic cells, prokaryotic cells, and archaeans. In eukaryotic cells, these fibers consist of a complex mesh of protein filaments and motor proteins that aid in cell movement and stabilize the cell.

Intermediate filaments are about 10 nm diameter and provide tensile strength for the cell. In the epithelial (skin) cells of the intestine, all three types of fibers are present. Microfilaments project into the villi, giving shape to the cell surface.

Why are intermediate filaments called that? ›

Initially designated 'intermediate' because their average diameter (10 nm) is between those of narrower microfilaments (actin) and wider myosin filaments found in muscle cells, the diameter of intermediate filaments is now commonly compared to actin microfilaments (7 nm) and microtubules (25 nm).

The intermediate filament (IF) network is one of the three cytoskeletal systems in the cell. IFs are widely distributed from the plasma membrane to the nucleus, providing mechanical and structural integrity for the cell (14; 38; 63).

Each filament is a twisted chain of identical globular actin molecules, all these molecules point in the same direction along the axis of the chain. Therefore an actin filament has a structural polarity, with a plus and a minus end. Actin filaments are thinner,more flexible, and generally shorter than microtubules.

The cytoskeleton of a cell consists of microtubules, actin filaments, and intermediate filaments. Microtubules are the largest of the three types of cytoskeletal fibres. They are made up of tubulin protein filaments. In contrast, actin filaments are the smallest, and they are made up of actin protein filaments.

Intermediate filaments are found throughout the cell and hold organelles in place.

The function of the filament is simply to hold up the anther, extending it up to an accessible part of the flower for pollinators reach, or for the wind to disperse the pollen.

Filament is a stalk-like structure that attaches to the base of the flower and supports the anther, which is the structure that produces pollen.

Medical Definition

filament. noun. fil·​a·​ment ˈfil-ə-mənt. : a single thread or a thin flexible threadlike object, process, or appendage. especially : an elongated thin series of cells attached one to another or a very long thin cylindrical single cell (as of some algae, fungi, or bacteria)

It brings together various aspects of the curriculum into meaningful association through a focus on broad student selected themes of study. It reflects the interdependent nature of the real world and engages the learner in real life experiences, in a more holistic manner.

Intermediate filaments consist of several intertwined strands of fibrous proteins. Intermediate filaments have no role in cell movement. Their function is purely structural. They bear tension, thus maintaining the shape of the cell, and anchor the nucleus and other organelles in place.

What does intermediate mean in biology? ›

An intermediate is a molecule that is formed from two or more reactants and then reacts further to give products. Most chemical reactions require more than one step, and an intermediate is the product of each step, except for the last one, after which the final products are produced.

Intermediate filaments (IFs) are 10nm in diameter and, therefore, intermediate in thickness between microfilaments and myosin thick filaments, or microfilaments and microtubules.

The intermediate filaments comprise the major component of the cytoskeleton and consist of five major subgroups—vimentin, keratins, desmin, neurofilaments, and glial fibrillary acidic protein (GFAP)—and a small number of minor subgroups (e.g., nestin, peripherin).

The subunits of intermediate filaments are elongated, not globular, and are associated in an antipolar manner. As a result, the overall filament has no polarity, and therefore no motor proteins move along intermediate filaments. Intermediate filaments are found only in complex multicellular organisms.

To form an intermediate filament, vimentin molecules first form dimers which then assemble to form tetramers that then associate laterally and longitudinally to assemble into mature 10nm-wide filaments of varying lengths.

In biology, a protein filament is a long chain of protein monomers, such as those found in hair, muscle, or in flagella. Protein filaments form together to make the cytoskeleton of the cell. They are often bundled together to provide support, strength, and rigidity to the cell.

A filament is the thin wire inside a light bulb that emits light when heated by an electric current. The incandescent light bulb makes light by heating a metal filament wire to a high temperature until it glows.

The primary function of intermediate filaments is to create cell cohesion and prevent the acute fracture of epithelial cell sheets under tension.

With unique assembly-disassembly dynamics and physical properties, cytoplasmic intermediate filaments play an important role in regulating cell shape and mechanical integrity.