TY  - JOUR
AU  - A.S. Coquel
AU  - Jean-Pascal Jacob
AU  - M. Primet
AU  - A. Demarez
AU  - Mariella Dimiccoli
AU  - T. Julou
AU  - L. Moisan
AU  - A. Lindner
AU  - H. Berry
ED  - : Stanislav Shvartsman, Princeton University
PY  - 2013//
TI  - Localization of protein aggregation in Escherichia coli is governed by diffusion and nucleoid macromolecular crowding effect
T2  - PCB
JO  - Plos Computational Biology
VL  - 9
IS  - 4
N2  - Aggregates of misfolded proteins are a hallmark of many age-related diseases. Recently, they have been linked to aging of Escherichia coli (E. coli) where protein aggregates accumulate at the old pole region of the aging bacterium. Because of the potential of E. coli as a model organism, elucidating aging and protein aggregation in this bacterium may pave the way to significant advances in our global understanding of aging. A first obstacle along this path is to decipher the mechanisms by which protein aggregates are targeted to specific intercellular locations. Here, using an integrated approach based on individual-based modeling, time-lapse fluorescence microscopy and automated image analysis, we show that the movement of aging-related protein aggregates in E. coli is purely diffusive (Brownian). Using single-particle tracking of protein aggregates in live E. coli cells, we estimated the average size and diffusion constant of the aggregates. Our results provide evidence that the aggregates passively diffuse within the cell, with diffusion constants that depend on their size in agreement with the Stokes-Einstein law. However, the aggregate displacements along the cell long axis are confined to a region that roughly corresponds to the nucleoid-free space in the cell pole, thus confirming the importance of increased macromolecular crowding in the nucleoids. We thus used 3D individual-based modeling to show that these three ingredients (diffusion, aggregation and diffusion hindrance in the nucleoids) are sufficient and necessary to reproduce the available experimental data on aggregate localization in the cells. Taken together, our results strongly support the hypothesis that the localization of aging-related protein aggregates in the poles of E. coli results from the coupling of passive diffusion-aggregation with spatially non-homogeneous macromolecular crowding. They further support the importance of “soft” intracellular structuring (based on macromolecular crowding) in diffusion-based protein localization in E. coli.
L1  - http://refbase.cvc.uab.es/files/CPJ2016.PDF
UR  - http://dx.doi.org/10.1371/journal.pcbi.1003038
N1  - exported from refbase (http://refbase.cvc.uab.es/show.php?record=2786), last updated on Tue, 25 Jun 2024 15:39:34 +0200
ID  - A.S. Coquel2013
ER  -