Review Article The motility and dynamic properties of intermediate filaments and their constituent proteins Ying-Hao Chou, Frederick W. Flitney, Lynne Chang, Melissa Mendez, Boris Grin, Robert D. Goldman ⁎ Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA ARTICLEINFORMATION ABSTRACT Article Chronology: Received 23 January 2007 Revised version received 1 April 2007 Accepted 5 April 2007 Available online 12 April 2007 Intermediate filament (IF) proteins exist in multiple structural forms within cells including mature IF, short filaments or ‘squiggles’, and non-filamentous precursors called particles. These forms are interconvertible and their relative abundance is IF type, cell type- and cell cycle stage-dependent. These structures are often associated with molecular motors, such as kinesin and dynein, and are therefore capable of translocating through the cytoplasm along microtubules. The assembly of mature IF from their precursor particles is also coupled to translation. These dynamic properties of IF provide mechanisms for regulating their reorganization and assembly in response to the functional requirements of cells. The recent findings that IF and their precursors are frequently associated with signaling molecules have revealed new functions for IF beyond their more traditional roles as mechanical integrators of cells and tissues. © 2007 Published by Elsevier Inc. Keywords: Vimentin Keratin Intermediate filaments Molecular motors Signal transduction Contents Introduction ........................................................... 2237 The dynamic properties of IF in interphase cells ..................................... 2237 IF organization within cells is altered in response to environmental stress ....................... 2238 The dynamic properties of IF in dividing cells ....................................... 2239 The functional significance of motile IF and their precursors .............................. 2239 The assembly of IF proteins is coupled to protein synthesis ............................... 2240 Future directions and conclusions ............................................... 2240 EXPERIMENTAL CELL RESEARCH 313 (2007) 2236 – 2243 ⁎ Corresponding author. Fax: +1 312 503 0954. E-mail address: r-goldman@northwestern.edu (R.D. Goldman). Abbreviations: cdk, cell cycle-dependent kinase; DM-EBS, Dowling–Meara epidermolysis bullosa simplex; FISH, fluorescence in situ hybridization; FRAP, fluorescence recovery after photobleaching; GFP, green fluorescent protein; IF, intermediate filament; IFAP, IF associated protein; MAP kinase, mitogen activated protein kinase; mTOR, mammalian target of rapamycin; NF, neurofilament; siRNA, small interfering RNA 0014-4827/$ – see front matter © 2007 Published by Elsevier Inc. doi:10.1016/j.yexcr.2007.04.008 available at www.sciencedirect.com www.elsevier.com/locate/yexcr