133 research outputs found
Cytoskeleton polarity is essential in determining orientational order in basal bodies of multi-ciliated cells
Synchronous and directed ciliary beating in trachea allows transport and
ejection of virus and dust from the body. This ciliary function depends on the
coordinated configuration of basal bodies (root of cilia) in apical cell
membrane. However, the mechanism for their formation remains unknown. In this
study, we show that the polarity in apical microtubule bundles plays a
significant role in the organization of basal bodies. A mathematical model
incorporating polarity has been formulated which provides a coherent
explanation and is able to reproduce experimental observations. We have
clarified both necessity ('why polarity is required for pattern formation') and
sufficiency ('how polarity works for pattern formation') of cytoskeleton
polarity for correct pattering of basal bodies with verification by
experimental data. This model further leads us to a possible mechanism for
cellular chirality.Comment: 30 pages, 8 figures (including Supporting Information), 2 table
A mass conserved reaction-diffusion system captures properties of cell polarity
Various molecules exclusively accumulate at the front or back of migrating
eukaryotic cells in response to a shallow gradient of extracellular signals.
Directional sensing and signal amplification highlight the essential properties
in the migrating cells, known as cell polarity. In addition to these, such
properties of cell polarity involve unique determination of migrating direction
(uniqueness of axis) and localized gradient sensing at the front edge
(localization of sensitivity), both of which may be required for smooth
migration. Here we provide the mass conservation system based on the
reaction-diffusion system with two components, where the mass of the two
components is always conserved. Using two models belonging to this mass
conservation system, we demonstrate through both numerical simulation and
analytical approximations that the spatial pattern with a single peak
(uniqueness of axis) can be generally observed and that the existent peak
senses a gradient of parameters at the peak position, which guides the movement
of the peak. We extended this system with multiple components, and we developed
a multiple-component model in which cross-talk between members of the Rho
family of small GTPases is involved. This model also exhibits the essential
properties of the two models with two components. Thus, the mass conservation
system shows properties similar to those of cell polarity, such as uniqueness
of axis and localization of sensitivity, in addition to directional sensing and
signal amplification.Comment: PDF onl
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