Various Types of Eukaryotic Cytoskeletal Proteins

Also known as: Actin filaments

Description: Microfilaments are cytoskeleton proteins that are approximately 5-9 nm in diameter and are made of two intertwined actin chains forming a double helix. They most often are present directly beneath the cell membrane and make up part of the eukaryotic cytoskeleton. They are responsible for the cell's shape, projections of the cell membrane, and forming the cleavage furrow during cellular replication. They also act with myosin to produce muscle contraction and play a large role in signal transduction.

Description: Intermediate filaments are tetrameric, meaning made of two parallel helices, cytoskeleton proteins that are approximately 10 nm in diameter and are stable components of the eukaryotic cytoskeleton. Along with microfilaments they bear tension to maintain the cell's shape, but they also organize the interior of the cell by anchoring organelles, are integrated into the structure of the nuclear envelope, and participating in cell junctions. Different types of intermediate filaments are present in different types of cells and structures

Description: Microtubules are hollow tubes or cylinders 25 nm in diameter that serve as eukaryotic cytoskeleton proteins. They are comprised of protofilaments, usually numbering 13, which are made up of alpha and beta tubulin Tubulin is a globular protein. They bind GTP for polymerization and are organized by the centrosome. In star-shaped sets they form the centrioles. Microtubule sets also can form wheel shapes to produce cilia and flagella. The proteins also play a role in the transport of vesicles and mitochondria, the formation of the mitotic spindle during cellular replication, and the synthesis of the cell wall in plant cells.

Description: Catenins are proteins found in complexes with cell adhesion molecules in animal cells. They extend from the cytoskeleton of one cell to the cytoskeleton of an adjacent cell by attachment to other cellular proteins called cadherins.

Facts: Origin: Latin catena ''chain''