The cytoskeleton

The cytoskeleton is a system of fibers, and filaments, located in the cytoplasm. Its functions are to transport cell structures, mitochondria and vesicles, for example, to anchor cell organelles, and to preserve the shape and structure of cells. The eukaryotic cytoskeleton consists of three main components, namely actin filaments, microtubules and intermediate filaments. What is more, a large number of proteins are linked to these main components which perform various and varied functions.

Actin’s filaments are made of polymerized protein actin and are organized in a double delight structure similar to that of fibers, with a diameter of about seven nanometers. They play an important role in the stabilization and modification of cell geometry as well as in the transport of vesicles. By binding to phalloidin, a substance belonging to the phallotoxin group, they can be labeled and detected by fluorescence microscopy. Microtubules are dynamic, hollow cylinders 25 nanometers in diameter, and are made up of polymers made up of tubulin subunits.

Thanks to their motor proteins dynein and kinesin, they allow intracellular transport over long distances and promote the attachment of cellular organelles. The intermediate filaments have structuring functions for the cell membrane and the nucleus. The main components are subdivided into six subtypes, namely acid and basic keratins, desmines (GFAB, desmin, vimentin, peripherin), lamin (lamin A, lamin B and lamin C), and neurofilaments (NF- L, internexin, NF-M, NF-A, nestin). Their diameter is halfway between that of the actin filaments and that of the microtubule.

The Aktinfilamenten consist of the polymerized protein Aktin and have a double helix filamentary structure as well as a diameter of about seven nanometers. They play an essential role in the stabilization or modification of cell geometry as well as in the transport of vesicles. By specifically binding to phalloidin, a substance in the phallotoxin group, they can be labeled and detected by fluorescence microscopy. Microtubules are dynamic polymers composed of tubulin subunits, which form a hollow cylinder with a diameter of about 25 nanometers.

Thanks to their motor proteins dynein and kinesin, they allow cells to carry out cell transport processes over long distances. They also encourage the fixation of cellular organelles. The main role of intermediate filaments is to structure the plasma membrane and the nucleus. These main components can be classified into six subtypes. Acid and basic keratin, desmin (GFAB, Desmin, Vimentin, Peripherin), Lamin (Lamin A, Lamin B and Lamin C) and Neurofilamenten (NF-L, Internexin, NF-M, NF-A, nestin) . Their diameter is between that of the Aktinfilamenten and that of the microtubules.

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