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Cell-size confinement effect on protein diffusion in crowded poly(ethylene)glycol solution

Chiho Watanabe1, Miho Yanagisawa

  • 1Department of Applied Physics, Faculty of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan. myanagi@cc.tuat.ac.jp.

Physical Chemistry Chemical Physics : PCCP
|March 16, 2018
PubMed

Insights

Cell confinement and macromolecular crowding surprisingly accelerate protein diffusion. This effect, observed in cell-mimicking microdroplets, depends on confinement size and crowding level, aiding diffusion in crowded cytoplasm.

Area of Science:

  • Cellular biology
  • Biophysics
  • Molecular dynamics

Background:

  • Macromolecular crowding and cell confinement are crucial for regulating molecular diffusion within cells.
  • Previous research indicates crowding generally slows diffusion.
  • The combined impact of confinement and crowding on diffusion remains unclear.

Purpose of the Study:

  • To investigate the effect of micrometric confinement on protein diffusion in a crowded cellular environment.
  • To elucidate how cell-like conditions influence molecular mobility.

Main Methods:

  • Utilized fluorescence correlation spectroscopy (FCS) to analyze protein diffusion.
  • Employed microdroplets with polymer solutions enclosed by lipid membranes to simulate cellular conditions.

Main Results:

  • A synergistic effect of crowding and micrometric confinement was found to accelerate protein diffusion on a sub-millisecond timescale.
  • The rate of diffusion acceleration was significantly influenced by the dimensions of the confined space and the extent of crowding.

Conclusions:

  • Cell-size confinement can enhance, rather than hinder, protein diffusion in highly crowded cellular environments.
  • These findings offer new insights into the biophysical regulation of molecular transport in live cells.

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