Intermediate filaments, microtubules, and actin filaments are the three major types of cytoskeletal filaments that provide structural support and help to maintain cell shape. Intermediate filaments are composed of fibrous proteins, such as keratins, vimentins, and laminins. These filaments are formed by the coiling of two intermediate filament proteins to create a dimer, which then pairs with another dimer to form a tetramer. Tetramers then join together laterally to form intermediate filaments. Intermediate filaments are strong and stable and provide resistance to mechanical stress and strain.