Intermediate filaments (IF) are proteins which are cytoplasmic or in the case of lamins, nuclear, that form part of the cytoskeletal structures of cells. IF are highly elastic, deformable and aid a cell retain its basic integrity.
There six basic types of IF. Types 1 and 2, Acidic or Keratin, found in epithelial or hair cells. Type 3, found in muscle and endothelial cells, Type 4, found in axons and neurons and Type 5, the nuclear Lamins.
Laminopathies (eg Progeria), can result from IF aberrations.