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.
A Bistable Model of Cell Polarity / M. Semplice, A. Veglio, G. Naldi, G. Serini, A. Gamba. - In: PLOS ONE. - ISSN 1932-6203. - 7:2(2012 Feb 23), pp. e30977.1-e30977.14.
|Titolo:||A Bistable Model of Cell Polarity|
|Parole Chiave:||MITOTIC SPINDLE ORIENTATION; TUMOR-SUPPRESSOR PTEN; DICTYOSTELIUM CELLS; PLASMA-MEMBRANE; PHOSPHATIDYLINOSITOL 4,5-BISPHOSPHATE; EPITHELIAL MORPHOGENESIS; SIGNAL-TRANSDUCTION; ACTIN CYTOSKELETON; POSITIVE FEEDBACK; PATTERN-FORMATION|
|Settore Scientifico Disciplinare:||Settore MAT/08 - Analisi Numerica|
Settore MAT/07 - Fisica Matematica
Settore BIO/13 - Biologia Applicata
Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
|Data di pubblicazione:||23-feb-2012|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1371/journal.pone.0030977|
|Appare nelle tipologie:||01 - Articolo su periodico|