Phases, morphologies, and transitions in a membrane model for the endoplasmic reticulum

Fuente: arXiv
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Main Authors: Alageshan, Jaya Kumar, Hatwalne, Yashodhan, Pandit, Rahul
Format: Preprint
Published: 2024
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author Alageshan, Jaya Kumar
Hatwalne, Yashodhan
Pandit, Rahul
author_facet Alageshan, Jaya Kumar
Hatwalne, Yashodhan
Pandit, Rahul
contents We introduce a novel model, comprising self-avoiding surfaces and incorporating edges and tubules, that is designed to characterize the structural morphologies and transitions observed within the endoplasmic reticulum (ER). By employing discretized models, we model smooth membranes with triangulated surfaces, and we utilize numerical variational methods to minimize energies associated with periodic morphologies. Our study obtains phases, their morphologies, and their transitions and examines their dependence on the membrane chemical potential, the line tensions, and the positive Gaussian curvature stiffness. By starting with diverse topological structures, we explore shape variations by using Surface Evolver, while maintaining fixed topology. Notably, we identify the region of parameter space where the model displays lamellae, with a lattice of helical edges connecting the layers; this resembles structures that have been observed in the rough ER. Furthermore, our investigation reveals an intricate phase diagram with periodic structures, including flat lamellar sheets, sponge phases, and configurations comprising tubules with junctions, which are akin to the morphology of the smooth ER. An estimation of lattice parameters is achieved through fluctuation analysis. Significantly, our model predicts a transition between homotopically equivalent lamellae, with helical edges and configurations featuring tubules with junctions.
format Preprint
id arxiv_https___arxiv_org_abs_2404_04611
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Phases, morphologies, and transitions in a membrane model for the endoplasmic reticulum
Alageshan, Jaya Kumar
Hatwalne, Yashodhan
Pandit, Rahul
Soft Condensed Matter
Biological Physics
We introduce a novel model, comprising self-avoiding surfaces and incorporating edges and tubules, that is designed to characterize the structural morphologies and transitions observed within the endoplasmic reticulum (ER). By employing discretized models, we model smooth membranes with triangulated surfaces, and we utilize numerical variational methods to minimize energies associated with periodic morphologies. Our study obtains phases, their morphologies, and their transitions and examines their dependence on the membrane chemical potential, the line tensions, and the positive Gaussian curvature stiffness. By starting with diverse topological structures, we explore shape variations by using Surface Evolver, while maintaining fixed topology. Notably, we identify the region of parameter space where the model displays lamellae, with a lattice of helical edges connecting the layers; this resembles structures that have been observed in the rough ER. Furthermore, our investigation reveals an intricate phase diagram with periodic structures, including flat lamellar sheets, sponge phases, and configurations comprising tubules with junctions, which are akin to the morphology of the smooth ER. An estimation of lattice parameters is achieved through fluctuation analysis. Significantly, our model predicts a transition between homotopically equivalent lamellae, with helical edges and configurations featuring tubules with junctions.
title Phases, morphologies, and transitions in a membrane model for the endoplasmic reticulum
topic Soft Condensed Matter
Biological Physics
url https://arxiv.org/abs/2404.04611