Limits...
A bistable model of cell polarity.

Semplice M, Veglio A, Naldi G, Serini G, Gamba A - PLoS ONE (2012)

Bottom Line: Cell membrane polarization is a fundamental process implicated in several basic biological phenomena, such as differentiation, proliferation, migration and morphogenesis of unicellular and multicellular organisms.We describe a simple, solvable model of cell membrane polarization based on the coupling of membrane diffusion with bistable enzymatic dynamics.The model can reproduce a broad range of symmetry-breaking events, such as those observed in eukaryotic directional sensing, the apico-basal polarization of epithelium cells, the polarization of budding and mating yeast, and the formation of Ras nanoclusters in several cell types.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Mathematics, Università dell'Insubria, Como, Italy.

ABSTRACT
Ultrasensitivity, as described by Goldbeter and Koshland, has been considered for a long time as a way to realize bistable switches in biological systems. It is not as well recognized that when ultrasensitivity and reinforcing feedback loops are present in a spatially distributed system such as the cell plasmamembrane, they may induce bistability and spatial separation of the system into distinct signaling phases. Here we suggest that bistability of ultrasensitive signaling pathways in a diffusive environment provides a basic mechanism to realize cell membrane polarity. Cell membrane polarization is a fundamental process implicated in several basic biological phenomena, such as differentiation, proliferation, migration and morphogenesis of unicellular and multicellular organisms. We describe a simple, solvable model of cell membrane polarization based on the coupling of membrane diffusion with bistable enzymatic dynamics. The model can reproduce a broad range of symmetry-breaking events, such as those observed in eukaryotic directional sensing, the apico-basal polarization of epithelium cells, the polarization of budding and mating yeast, and the formation of Ras nanoclusters in several cell types.

Show MeSH

Related in: MedlinePlus

The dynamics of the simulated 3D spatially distributed model for different times.The colorbar is the same as in Fig. 9, the major cell perimeter is the one considered in Fig. 9.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3285628&req=5

pone-0030977-g009: The dynamics of the simulated 3D spatially distributed model for different times.The colorbar is the same as in Fig. 9, the major cell perimeter is the one considered in Fig. 9.

Mentions: The kimograph in Fig. 8b shows the time evolution of simulated PIP3 levels along the major cell perimeter, while Fig. 9 shows this very same dynamics in 3D. Similarly to what observed in experiments, a transient, uniform increase in PIP3 levels is followed by a second regime where localized PIP3 patches phase nucleate and grow competitively in a PIP2-rich sea. In both the experiments and simulations, the speed of patch growth slows down with time. The features of the simulated dynamics are therefore completely consistent with the experimental data.


A bistable model of cell polarity.

Semplice M, Veglio A, Naldi G, Serini G, Gamba A - PLoS ONE (2012)

The dynamics of the simulated 3D spatially distributed model for different times.The colorbar is the same as in Fig. 9, the major cell perimeter is the one considered in Fig. 9.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3285628&req=5

pone-0030977-g009: The dynamics of the simulated 3D spatially distributed model for different times.The colorbar is the same as in Fig. 9, the major cell perimeter is the one considered in Fig. 9.
Mentions: The kimograph in Fig. 8b shows the time evolution of simulated PIP3 levels along the major cell perimeter, while Fig. 9 shows this very same dynamics in 3D. Similarly to what observed in experiments, a transient, uniform increase in PIP3 levels is followed by a second regime where localized PIP3 patches phase nucleate and grow competitively in a PIP2-rich sea. In both the experiments and simulations, the speed of patch growth slows down with time. The features of the simulated dynamics are therefore completely consistent with the experimental data.

Bottom Line: Cell membrane polarization is a fundamental process implicated in several basic biological phenomena, such as differentiation, proliferation, migration and morphogenesis of unicellular and multicellular organisms.We describe a simple, solvable model of cell membrane polarization based on the coupling of membrane diffusion with bistable enzymatic dynamics.The model can reproduce a broad range of symmetry-breaking events, such as those observed in eukaryotic directional sensing, the apico-basal polarization of epithelium cells, the polarization of budding and mating yeast, and the formation of Ras nanoclusters in several cell types.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Mathematics, Università dell'Insubria, Como, Italy.

ABSTRACT
Ultrasensitivity, as described by Goldbeter and Koshland, has been considered for a long time as a way to realize bistable switches in biological systems. It is not as well recognized that when ultrasensitivity and reinforcing feedback loops are present in a spatially distributed system such as the cell plasmamembrane, they may induce bistability and spatial separation of the system into distinct signaling phases. Here we suggest that bistability of ultrasensitive signaling pathways in a diffusive environment provides a basic mechanism to realize cell membrane polarity. Cell membrane polarization is a fundamental process implicated in several basic biological phenomena, such as differentiation, proliferation, migration and morphogenesis of unicellular and multicellular organisms. We describe a simple, solvable model of cell membrane polarization based on the coupling of membrane diffusion with bistable enzymatic dynamics. The model can reproduce a broad range of symmetry-breaking events, such as those observed in eukaryotic directional sensing, the apico-basal polarization of epithelium cells, the polarization of budding and mating yeast, and the formation of Ras nanoclusters in several cell types.

Show MeSH
Related in: MedlinePlus