Elements of the Cytoskeleton

Cytoskeleton

A system of dynamic protein filaments in eukaryotic cells that provides structure, mechanical support, and helps organize organelles.

Actin Filaments

Flexible helical polymers with a diameter of 7 nm, beneath the plasma membrane, involved in cell locomotion and cytoskeleton organization.

Intermediate Filaments

Rope-like fibers made of IF proteins with a diameter of 10 nm, providing mechanical strength and anchoring cells at junctions.

Microtubules

Long, hollow cylinders with an outer diameter of 25 nm, involved in vesicle transport, cell division, and the motility of cilia and flagella.

Function of Cytoskeleton

Gives cell shape, provides mechanical support, organizes organelles, and facilitates movement.

Structure of Actin Filaments

Composed of flexible helical polymer chains that contribute to cell shape and motility.

Function of Intermediate Filaments

Provides mechanical strength, determines cell shape, and maintains connections between cells.

Example of Intermediate Filaments

Keratin in epithelial cells, which maintains the structure and strength of the tissue.

Microtubule Function

Necessary for intracellular transport, cell division (spindle formation), and motility of cilia and flagella.

Coiled-Coil Dimer

The basic structure of intermediate filaments formed by the coiling of two alpha-helices.

Subunit Assembly

Cytoskeleton filaments are made up of protein subunits that self-assemble into larger structures.

Cytoskeletal Elements

The three main types are actin filaments, intermediate filaments, and microtubules, differing in structure and function.

Dynamic Nature of Cytoskeleton

Cytoskeletal filaments are dynamic and adaptable, allowing for cellular changes and movements.