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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.

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Model of cell polarization for budding yeast.With respect to the scheme in Fig. 1, we identify , , , .
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pone-0030977-g012: Model of cell polarization for budding yeast.With respect to the scheme in Fig. 1, we identify , , , .

Mentions: The Cdc24 GTPase is activated by Cdc42 via the scaffold protein Bem1, resulting in the amplifying feedback loop of Fig. 12. Moreover, several GTPase activating proteins (GAP), such as Rga2, can negatively regulate Cdc42 [44]. The structure of this signaling network fits with the abstract scheme (1–8, Fig. 1) once we identify , , , .


A bistable model of cell polarity.

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

Model of cell polarization for budding yeast.With respect to the scheme in Fig. 1, we identify , , , .
© Copyright Policy
Related In: Results  -  Collection

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

pone-0030977-g012: Model of cell polarization for budding yeast.With respect to the scheme in Fig. 1, we identify , , , .
Mentions: The Cdc24 GTPase is activated by Cdc42 via the scaffold protein Bem1, resulting in the amplifying feedback loop of Fig. 12. Moreover, several GTPase activating proteins (GAP), such as Rga2, can negatively regulate Cdc42 [44]. The structure of this signaling network fits with the abstract scheme (1–8, Fig. 1) once we identify , , , .

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