Fusion and scission of membranes: ubiquitous topological transformations in cells

Abstract
2016 Nobel Prizes were awarded to Yoshinori Ohsumi for autophagy and to David Thouless, Duncan Haldane and Michael Kosterlitz for topological transitions. Both of these phenomena are intrinsically related when it comes to membranes. Here, we give a brief account on topological transformations of lipid membranes, commonly known as membrane fusion and membrane scission, and introduce the underlying topological invariant, the genus. The genus of a shape is a useful concept to distinguish unambiguously the processes of membrane fusion/scission and offers a simple method to describe complex, cellular membrane structures, such as fenestrated cristae. We distinguish and highlight the connection between topological transformations of lipid membranes and the recent awards, and point out the extraordinarily large number of topological changes during autophagy.

Synopsis
Remodeling of lipid membranes involves gradual bending as well as abrupt events: membrane fusion and membrane scission. Such discontinuous changes alter the number of individual (separate) membranes or the number of (torus‐like) holes within the membrane structure: the topology of the structure changes. Here, we review cell membrane remodeling from a topological viewpoint, highlight the large number of topological changes during autophagy and link the two 2016 Nobel prizes honoring autophagy and topology.

Source: Traffic - August 1, 2017 Category: Research Authors: Roland L. Knorr, Noboru Mizushima, Rumiana Dimova Tags: TRAFFIC INTERCHANGE Source Type: research