TY - JOUR
T1 - Dynamics of the bacterial intermediate filament crescentin in vitroand in vivo
AU - Esue, Osigwe
AU - Rupprecht, Laura
AU - Sun, Sean X.
AU - Wirtz, Denis
PY - 2010/1/25
Y1 - 2010/1/25
N2 - Background: Crescentin, the recently discovered bacterial intermediate filament protein, organizes into an extended filamentous structure that spans the length of the bacterium Caulobacter crescentus and plays a critical role in defining its curvature. The mechanism by which crescentin mediates cell curvature and whether crescentin filamentous structures are dynamic and/or polar are not fully understood. Methodology/Principal Findings:Using light microscopy, electron microscopy and quantitative rheology, we investigated the mechanics and dynamics of crescentin structures. Live-cell microscopy reveals that crescentin forms structures in vivo that undergo slow remodeling. The exchange of subunits between these structures and a pool of unassembled subunits is slow during the life cycle of the cell however; in vitro assembly and gelation of C. crescentus crescentin structures are rapid. Moreover, crescentin forms filamentous structures that are elastic, solid-like, and, like other intermediate filaments, can recover a significant portion of their network elasticity after shear. The assembly efficiency of crescentin is largely unaffected by monovalent cations (K+, Na+), but is enhanced by divalent cations (Mg2+, Ca2+), suggesting that the assembly kinetics and micromechanics of crescentin depend on the valence of the ions present in solution. Conclusions/Significance: These results indicate that crescentin forms filamentous structures that are elastic, labile, and stiff, and that their low dissociation rate from established structures controls the slow remodeling of crescentin in C. crescentus.
AB - Background: Crescentin, the recently discovered bacterial intermediate filament protein, organizes into an extended filamentous structure that spans the length of the bacterium Caulobacter crescentus and plays a critical role in defining its curvature. The mechanism by which crescentin mediates cell curvature and whether crescentin filamentous structures are dynamic and/or polar are not fully understood. Methodology/Principal Findings:Using light microscopy, electron microscopy and quantitative rheology, we investigated the mechanics and dynamics of crescentin structures. Live-cell microscopy reveals that crescentin forms structures in vivo that undergo slow remodeling. The exchange of subunits between these structures and a pool of unassembled subunits is slow during the life cycle of the cell however; in vitro assembly and gelation of C. crescentus crescentin structures are rapid. Moreover, crescentin forms filamentous structures that are elastic, solid-like, and, like other intermediate filaments, can recover a significant portion of their network elasticity after shear. The assembly efficiency of crescentin is largely unaffected by monovalent cations (K+, Na+), but is enhanced by divalent cations (Mg2+, Ca2+), suggesting that the assembly kinetics and micromechanics of crescentin depend on the valence of the ions present in solution. Conclusions/Significance: These results indicate that crescentin forms filamentous structures that are elastic, labile, and stiff, and that their low dissociation rate from established structures controls the slow remodeling of crescentin in C. crescentus.
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U2 - 10.1371/journal.pone.0008855
DO - 10.1371/journal.pone.0008855
M3 - Article
C2 - 20140233
AN - SCOPUS:77749309961
SN - 1932-6203
VL - 5
JO - PloS one
JF - PloS one
IS - 1
M1 - e8855
ER -