Intermediate filaments are a component of cytoskeleton. They are around 10 nm, and are present in both cytoplasm and nucleus. These help provide the cell with mechanical strength and are also strong and stable due to the packing of coiled fibrillar proteins in a rope like structure. The different types of intermediate filaments that can be found in the cytoplasm of different cells can be used in tumour characterisation techniques within the health and research industries. Different categories of cytoplasmic intermediate filaments are found in; the epithelia as keratins, the connective tissue as vimentin, and the nerve cells as neurofilaments. The main type of intermediate filaments found in the nucleus are called nuclear lamins and are present in all nucleated cells, nuclear lamins lie just underneath the inner face of the nuclear envelope and provide mechanical strength to the nucleus as well as providing attachment sites for the chromosomes, but do break down during mitosis cell division .
Intermediate Filaments, are also called microfilaments, form long bands of tetrameric subunits. Accessory filaments help to keep the bundles together. For example, Plectin links the intermediate filaments to actin tubule bundles, myosin II and microtubles. This proten also binds intermediate filaments to the plasma membrane. Most of the intermediate filaments are cross linked and use the accessory filaments to do so.
These filaments have a diameter of 5-9nm .