by Robert Kirmse, Stephanie Portet, Norbert Mücke, Ueli Aebi and Harald Herrmann and Jörg Langowski
Abstract:
In vitro assembly of intermediate filament proteins is a very rapid process. It starts without significant delay by lateral association of tetramer complexes into unit-length filaments (ULFs) after raising the ionic strength from low salt to physiological conditions (100 mM KCl). We employed electron and scanning force microscopy complemented by mathematical modeling to investigate the kinetics of in vitro assembly of human recombinant vimentin. From the average length distributions of the resulting filaments measured at increasing assembly times we simulated filament assembly and estimated specific reaction rate parameters. We modeled eight different potential pathways for vimentin filament elongation. Comparing the numerical with the experimental data we conclude that a two-step mechanism involving rapid formation of ULFs followed by ULF and filament annealing is the most robust scenario for vimentin assembly. These findings agree with the first two steps of the previously proposed three-step assembly model (Herrmann, H., and Aebi, U. (1998) Curr. Opin. Struct. Biol. 8, 177-185). In particular, our modeling clearly demonstrates that end-to-end annealing of ULFs and filaments is obligatory for forming long filaments, whereas tetramer addition to filament ends does not contribute significantly to filament elongation.
Reference:
A quantitative kinetic model for the in vitro assembly of intermediate filaments from tetrameric vimentin. (Robert Kirmse, Stephanie Portet, Norbert Mücke, Ueli Aebi and Harald Herrmann and Jörg Langowski), In Journal of Biological Chemistry, volume 282, 2007.
Bibtex Entry:
@ARTICLE{Kirmse2007,
author = {Robert Kirmse and Stephanie Portet and Norbert Mücke and Ueli Aebi
and Harald Herrmann and Jörg Langowski},
title = {A quantitative kinetic model for the in vitro assembly of intermediate
filaments from tetrameric vimentin.},
journal = {Journal of Biological Chemistry},
year = {2007},
volume = {282},
pages = {18563--18572},
number = {25},
month = {Jun},
abstract = {In vitro assembly of intermediate filament proteins is a very rapid
process. It starts without significant delay by lateral association
of tetramer complexes into unit-length filaments (ULFs) after raising
the ionic strength from low salt to physiological conditions (100
mM KCl). We employed electron and scanning force microscopy complemented
by mathematical modeling to investigate the kinetics of in vitro
assembly of human recombinant vimentin. From the average length distributions
of the resulting filaments measured at increasing assembly times
we simulated filament assembly and estimated specific reaction rate
parameters. We modeled eight different potential pathways for vimentin
filament elongation. Comparing the numerical with the experimental
data we conclude that a two-step mechanism involving rapid formation
of ULFs followed by ULF and filament annealing is the most robust
scenario for vimentin assembly. These findings agree with the first
two steps of the previously proposed three-step assembly model (Herrmann,
H., and Aebi, U. (1998) Curr. Opin. Struct. Biol. 8, 177-185). In
particular, our modeling clearly demonstrates that end-to-end annealing
of ULFs and filaments is obligatory for forming long filaments, whereas
tetramer addition to filament ends does not contribute significantly
to filament elongation.},
doi = {10.1074/jbc.M701063200},
institution = {Division of Biophysics of Macromolecules, German Cancer Research
Center, Heidelberg, Germany.},
keywords = {Data Interpretation, Statistical; Escherichia coli, metabolism; Humans;
Intermediate Filaments, metabolism; Ions; Kinetics; Microscopy, Atomic
Force; Microscopy, Electron; Models, Biological; Models, Theoretical;
Potassium Chloride, pharmacology; Protein Conformation; Sensitivity
and Specificity; Time Factors; Vimentin, chemistry},
language = {eng},
medline-pst = {ppublish},
owner = {sportet},
pii = {M701063200},
pmid = {17403663},
timestamp = {2013.11.13},
url = {http://dx.doi.org/10.1074/jbc.M701063200}
}