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

Bistability region, yellow region (II)-(III), as a function of the level of external renormalized stimulation  for . The purple line corresponds to phase coexistence (polarization) and is an attractor for the polarization dynamics. The two stable domains, blue (IV) and red (I), correspond to the two  and  stable phases.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3285628&req=5

pone-0030977-g003: Bistability region, yellow region (II)-(III), as a function of the level of external renormalized stimulation for . The purple line corresponds to phase coexistence (polarization) and is an attractor for the polarization dynamics. The two stable domains, blue (IV) and red (I), correspond to the two and stable phases.

Mentions: Patterning is possible only if the enzyme ratio lies in the bistability region shown in Fig. 3 (see Supplementary Material Text S1). The enzyme ratio may therefore also be called a bistability parameter for the pathway of Fig. 1.


A bistable model of cell polarity.

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

Bistability region, yellow region (II)-(III), as a function of the level of external renormalized stimulation  for . The purple line corresponds to phase coexistence (polarization) and is an attractor for the polarization dynamics. The two stable domains, blue (IV) and red (I), correspond to the two  and  stable phases.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0030977-g003: Bistability region, yellow region (II)-(III), as a function of the level of external renormalized stimulation for . The purple line corresponds to phase coexistence (polarization) and is an attractor for the polarization dynamics. The two stable domains, blue (IV) and red (I), correspond to the two and stable phases.
Mentions: Patterning is possible only if the enzyme ratio lies in the bistability region shown in Fig. 3 (see Supplementary Material Text S1). The enzyme ratio may therefore also be called a bistability parameter for the pathway of Fig. 1.

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