The Structure and Function Of Intermediate Filament Networks In Mammalian Cells

Intermediate filaments (IF) are major cytoskeletal components found in most mammalian cells. One of the most intriguing properties of IF is their high degree of variability with regard to their structural subunit proteins. This ariability is most evident when one compares the protein composition of IF from different cell types. For example, nerve cell IF (neurofilaments) contain the so-called neurofilament triplet proteins, while different epithelial cells contain two or more of the family of IF proteins called keratins. Indeed other cell types appear to have primarily a single subunit species such as in fibroblasts (vimentin, decamin) and muscle cells (desmin). In the specific case of the nervous system, there is very little information available on specific functions of neurofilaments, although they are thought to be involved in nerve cell shape formation and maintenance, as well as in axoplasmic transport and flow.