Three-dimensional morphodynamic simulations of macropinocytic cups

Saito, Nen; Sawai, Shujiro

doi:10.1016/j.isci.2021.103087

Cited by 22 publications

(11 citation statements)

References 87 publications

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“…In these images the surrounding bare membrane is rendered to be invisible. These simulated dynamics resemble those calculated by another model of macropinocytic cups [35], which was based on reaction-diffusion dynamics coupled to active forces.…”

Section: Multiple Curvaturesupporting

confidence: 60%

Theoretical model of membrane protrusions driven by curved active proteins

Ravid¹,

Penič²,

Mimori-Kiyosue³

et al. 2023

Preprint

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Eukaryotic cells intrinsically change their shape, by changing the composition of their membrane and by restructuring their underlying cytoskeleton. We present here further studies and extensions of a minimal physical model, describing a closed vesicle with mobile curved membrane protein complexes. The cytoskeletal forces describe the protrusive force due to actin polymerization which is recruited to the membrane by the curved protein complexes. We characterize the phase diagrams of this model, as function of the magnitude of the active forces, nearest-neighbor protein interactions and the proteins' spontaneous curvature. It was previously shown that this model can explain the formation of lamellipodia-like flat protrusions, and here we explore the regimes where the model can also give rise to filopodia-like tubular protrusions. We extend the simulation with curved components of both convex and concave species, where we find the formation of complex ruffled clusters, as well as internalized invaginations that resemble the process of endocytosis and macropinocytosis. We alter the force model representing the cytoskeleton to simulate the effects of bundled instead of branched structure, resulting in shapes which resemble filopodia.

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Section: Multiple Curvaturesupporting

confidence: 60%

Theoretical model of membrane protrusions driven by curved active proteins

Ravid¹,

Penič²,

Mimori-Kiyosue³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Yet, even within these limitations, it readily reproduces an expanding cup that closes at the lip, and one that does not close at the lip, but elongates, as in base closure. The model of Saito and Sawai 46 , although enacted differently to our model, also incorporates the propositions of actin polymerization around PIP3 domains and domain stalling, and likewise reproduces cup formation and closure at the lip, indicating that these are robust consequences of the initial assumptions.…”

Section: Discussionmentioning

confidence: 83%

The formation and closure of macropinocytic cups in a model system

Lutton

Coker

Paschke³

et al. 2022

Preprint

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Macropinocytosis is a conserved endocytic process where cells take up medium into micron-sized vesicles. In Dictyostelium, macropinocytic cups form around domains of PIP3 in the plasma membrane and extend by actin polymerization. Using lattice light-sheet microscopy, we describe how cups originate, are supported by an F-actin scaffold and shaped by a ring of actin polymerization, created around PIP3 domains. How cups close is unknown. We find two ways: lip closure, where actin polymerization at the lip is re-directed inwards; and basal closure, where it stretches the cup, eventually causing membrane delamination and vesicle sealing. Cups grow as expanding waves of actin polymerization that travel across the cell surface, capturing new membrane. We propose that cups close when these waves stall. This 'stalled wave' hypothesis is tested through a conceptual model, where the interplay of forces from actin polymerization and membrane tension recreates many of our observations.

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“…Therefore, some other new models consider only a single variable for the membrane together with a global feedback to account for the mass-conservation condition for a single concentration [17,32,38]. When the dynamics of the concentration at the membrane is combined with other membrane concentrations more complex models including also excitable signalling networks are developed [39,47,48,55]. In contrast with such models, in this study we chose an existing complex model where the condition of bistability is finely tuned [23] and add the global feedback condition to account for the conservation of the protein.…”

Section: Discussionmentioning

confidence: 99%

Mass-Conservation Increases Robustness in Stochastic Reaction-Diffusion Models of Cell Crawling

Moreno

Alonso

2022

Front. Phys.

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The process of polarization determines the head and tail of single cells. A mechanism of this kind frequently precedes the subsequent cell locomotion and it determines the direction of motion. The process of polarization has frequently been described as a reaction-diffusion mechanism combined with a source of stochastic perturbations. We selected a particular model of amoeboid cell crawling for the motion of Dictyostelium discoideum and studied the interplay between pattern formation and locomotion. Next, we integrated the model in a two-dimensional domain considering the shape deformations of the cells in order to characterize the dynamics. We observed that the condition of pattern formation is finely tuned and we propose a modification based on the use of a mass-conservation constraint to substantially increase the robustness of the mathematical model.

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Three-dimensional morphodynamic simulations of macropinocytic cups

Cited by 22 publications

References 87 publications

Theoretical model of membrane protrusions driven by curved active proteins

Theoretical model of membrane protrusions driven by curved active proteins

The formation and closure of macropinocytic cups in a model system

Mass-Conservation Increases Robustness in Stochastic Reaction-Diffusion Models of Cell Crawling

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