An expanded view of the eukaryotic cytoskeleton

Abstract

A rich and ongoing history of cell biology research has defined the major polymer systems of the eukaryotic cytoskeleton. Recent studies have identified additional proteins that form filamentous structures in cells and can self-assemble into linear polymers when purified. This suggests that the eukaryotic cytoskeleton is an even more complex system than previously considered. In this essay, I examine the case for an expanded definition of the eukaryotic cytoskeleton and present a series of challenges for future work in this area.

FIGURE 1:

Nontraditional cytoskeletal filaments in vitro and in cells. Top, cytidine triphosphate synthase filaments (green) in the Drosophila egg chamber and electron microscopy (EM) of purified Escherichia coli CtpS filaments. Middle, endogenous Pil1 filaments in outlined S. pombe cells and EM of purified recombinant Pil1 tubules. Bottom, electron cryotomography of helical ESCRT-III–dependent filaments at abscission site and EM of purified Snf7 (“activated” R52E mutant). (Images reprinted with permission from Ingerson-Mahar et al., 2010; Noree et al., 2010; Guizetti et al., 2011; Kabeche et al., 2011; Henne et al., 2012.)