Intermediate filaments and tissue repair

Intermediate filaments (IFs), along with microtubules and microfilaments, comprise the organized, cytoplasmic networks commonly called the cytoskeleton. A large multigene family (>67) encodes proteins able to self-assemble into 10- to 12-nm-wide IFs in the cytoplasm and nucleus. Individual genes are regulated in a tissue-, cell type-, and context-dependent fashion, the significance of which is not yet understood. A major function fulfilled by all types of IFs is to contribute to the maintenance of cellular integrity in the presence of mechanical stress. Another emerging function is to act as a scaffold that binds and regulates the activity of several types of effector proteins, for example, receptors, kinases, adaptors, and heat shock proteins. Here we review the literature showing that modulation of cytoplasmic IFs occurs rapidly after injury to a variety of tissues and that such changes play an important role in the context of a timely repair response.