Interactions between model inclusions on closed lipid bilayer membranes

Abstract

Protein inclusions in the membranes of living cells interact via the deformations they impose on that membrane. Such membrane-mediated interactions lead to sorting and self-assembly of the inclusions, as well as to membrane remodelling, crucial for many biological processes. For the past decades, theory, numerical calculations and experiments have been employing simplified models for proteins to gain quantitative insights into their behaviour. Despite challenges arising from nonlinearities in the equations, the multiple length scales involved, and the non-additive nature of the interactions, recent progress now enables for the first time a direct comparison between theoretical and numerical predictions and experiments. We review the current knowledge on the biologically most relevant case, inclusions on lipid membranes with a closed surface, and discuss challenges and opportunities for further progress.

Membrane-Mediated Interactions Between Protein Inclusions

“…In this mini-review we do not discuss the experimental studies. Interested readers are referred to Refs ( Bitbol et al, 2018 ; Idema and Kraft, 2019 ).…”

More than just a barrier: using physical models to couple membrane shape to cell function

“…93,94 If there are multiple particles present on the membrane, they can interact with each other through the deformations they induce, which can lead to an attractive interaction and the emergence of collective behavior. [95][96][97][98][99][100] Cooperative wrapping is a result of the interplay of bending and adhesion energy such that multiple wrapped particles can self-assemble into membrane tubes 101 linear aggregates, 102 hexagonal arrays 103 or rings. 104 In contrast, long parallel cylinders in globally flat membranes are predicted to repel each other.…”

Membrane Shape Remodeling by Protein Crowding

“…A wide range of biophysical mechanisms cause tube formation, such as the adsorption of intrinsically curved proteins [8,9,10,11], internal and external protein scaffolds [12,13], local pulling forces [14], membrane compression [15], osmotic deflation [16,17], and protein crowding [18,18,19]. Protein crowding, i.e., the accumulation of proteins in a confined membrane domain is a phenomenon that is ubiquitous in biological membranes, which typically contain a multitude of domains with densely packed proteins of different size and where an overexpression of specific proteins or bio-polymers can be a disease marker.…”