Biological & Soft Matter Seminar: Understanding membrane processes at ultra large scales via lattice simulations

Zoom: https://tau-ac-il.zoom.us/j/88904888353?pwd=dDIwaXRxSjlsVElkR0dXdTNPTGhnZz09

Abstract: 

Many processes involve large scale changes in the lateral organization of biological membranes. Some of them span a very wide range of length and time scales that cannot be captured even by highly coarse-grained molecular models (let alone by fully atomistic ones). This great challenge of simulating collective cellular phenomena may be addressed by lattice models that are much cheaper computationally than molecular ones. Apart from their computational simplicity, the attractiveness of lattice simulations also lies in their minimal, semi-phenomenological, nature which helps identifying the most essential mechanisms that govern the physical behavior of complex systems. In the talk, I will present results from two recent research projects involving lattice simulations of large membranes: One is the study of the aggregation of immunological synapse - a micrometer-size circular domain formed within 30 minutes from the attachments of a T-cell to an Antigen Presenting Cell  (APC) [1,2] . The other is the study of formation of heterogeneous liquid ordered domains in mixtures containing saturated and unsaturated lipids with Cholesterol [3,4].  In both studies, the simulations provide new insights into the multi-scale structure and dynamics of the investigated systems. 

[1] N. Dharan and O. Farago, Formation of semi-dilute adhesion domains driven by weak elasticity-mediated interactions, Soft Matter 12, 6649 (2016).

[2] N. Dharan and O. Farago, Interplay between membrane elasticity and active cytoskeleton forces regulates the aggregation dynamics of the immunological synapse, Soft Matter 13, 6938 (2017).

[3] T. Sarkar and O. Farago, Minimal lattice model of lipid membranes with liquid-ordered domains, Phys. Rev. Res. 3, L042030 (2021).

[4] T. Sarkar and O. Farago, Lattice model of ternary mixtures of lipids and cholesterol with tunable domain sizes, arXiv:2203.03269 (2022).