Membrane bending: the power of protein imbalance

Derganc, Jure; Antonny, Bruno; Čopič, Alenka

doi:10.1016/j.tibs.2013.08.006

Cited by 49 publications

(44 citation statements)

References 85 publications

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“…At the plasma membrane, asymmetric protein crowding leads to membrane bending to release the lateral pressure (Derganc et al, 2013; Stachowiak et al, 2010; Stachowiak et al, 2012). The effects of crowding differ in the case of LDs, where a surfactant monolayer covering a hydrophobic phase is more difficult to deform than a bilayer membrane (Thiam et al, 2013b).…”

Section: Discussionmentioning

confidence: 99%

Protein Crowding Is a Determinant of Lipid Droplet Protein Composition

et al. 2015

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Summary Lipid droplets (LD) are lipid storage organelles that grow or shrink, depending on the availability of metabolic energy. Proteins recruited to LDs mediate many metabolic functions, including phosphatidylcholine and triglyceride synthesis. How the LD protein composition is tuned to the supply and demand for lipids remains unclear. We show that LDs, in contrast to other organelles, have limited capacity for protein binding. Consequently, macromolecular crowding plays a major role in determining LD protein composition. During lipolysis, when LDs and their surfaces shrink, some, but not all, proteins become displaced. In vitro studies show that macromolecular crowding, rather than changes in monolayer lipid composition, causes proteins to fall off the LD surface. As predicted by a crowding model, proteins compete for binding to the surfaces of LDs. Moreover, the LD binding affinity determines protein localization during lipolysis. Our findings identify protein crowding as an important principle in determining LD protein composition.

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Section: Discussionmentioning

confidence: 99%

Protein Crowding Is a Determinant of Lipid Droplet Protein Composition

et al. 2015

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“…The beclin-1-interacting transmembrane ER Box 2. Principles for the generation of membrane curvature by protein action Generally, the modeling of cell membranes to yield curvature and to shape organelles, vesicles and tubules is thought to depend on several different principles (see box figure) (for recent reviews, see Derganc et al, 2013;Kirchhausen, 2012;Kozlov et al, 2014). An asymmetric distribution of membrane lipids causes membrane bending if the head groups on the two sides are of different sizes.…”

Section: Phagophore Nucleationmentioning

confidence: 99%

Membrane dynamics in autophagosome biogenesis

Carlsson

Simonsen

2015

Journal of Cell Science

187

169

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Bilayered phospholipid membranes are vital to the organization of the living cell. Based on fundamental principles of polarity, membranes create borders allowing defined spaces to be encapsulated. This compartmentalization is a prerequisite for the complex functional design of the eukaryotic cell, yielding localities that can differ in composition and operation. During macroautophagy, cytoplasmic components become enclosed by a growing double bilayered membrane, which upon closure creates a separate compartment, the autophagosome. The autophagosome is then primed for fusion with endosomal and lysosomal compartments, leading to degradation of the captured material. A large number of proteins have been found to be essential for autophagy, but little is known about the specific lipids that constitute the autophagic membranes and the membrane modeling events that are responsible for regulation of autophagosome shape and size. In this Commentary, we review the recent progress in our understanding of the membrane shaping and remodeling events that are required at different steps of the autophagy pathway.This article is part of a Focus on Autophagosome biogenesis. For further reading, please see related articles: 'ERES: sites for autophagosome biogenesis and maturation?' by Jana SanchezWandelmer et al. (J. Cell Sci. 128,(185)(186)(187)(188)(189)(190)(191)(192) and 'WIPI proteins: essential PtdIns3P effectors at the nascent autophagosome' by Tassula Proikas-Cezanne et al. (J. Cell Sci. 128,(207)(208)(209)(210)(211)(212)(213)(214)(215)(216)(217).

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“…One way in which this can be achieved are shape changes, because all deviations from a spherical shape will decrease the volume-to-surface ratio. Non-spherical shapes of membranes can be dictated by proteins or by changes in lipid distribution (Derganc et al, 2013;Frolov et al, 2011;Heald and Cohen-Fix, 2014;Rafelski and Marshall, 2008). Manipulation of the balance of membrane influx and efflux pathways can also increase or decrease the volume of the organellar envelope.…”

Section: Introductionmentioning

confidence: 99%

Organelle size control – increasing vacuole content activates SNAREs to augment organelle volume through homotypic fusion

Desfougères

Neumann²,

Mayer

2016

Journal of Cell Science

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Cells control the size of their compartments relative to cell volume, but there is also size control within each organelle. Yeast vacuoles neither burst nor do they collapse into a ruffled morphology, indicating that the volume of the organellar envelope is adjusted to the amount of content. It is poorly understood how this adjustment is achieved. We show that the accumulating content of yeast vacuoles activates fusion of other vacuoles, thus increasing the volume-to-surface ratio. Synthesis of the dominant compound stored inside vacuoles, polyphosphate, stimulates binding of the chaperone Sec18/NSF to vacuolar SNAREs, which activates them and triggers fusion. SNAREs can only be activated by lumenal, not cytosolic, polyphosphate ( polyP). Control of lumenal polyP over SNARE activation in the cytosol requires the cytosolic cyclin-dependent kinase Pho80-Pho85 and the R-SNARE Nyv1. These results suggest that cells can adapt the volume of vacuoles to their content through feedback from the vacuole lumen to the SNAREs on the cytosolic surface of the organelle.

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Membrane bending: the power of protein imbalance

Cited by 49 publications

References 85 publications

Protein Crowding Is a Determinant of Lipid Droplet Protein Composition

Protein Crowding Is a Determinant of Lipid Droplet Protein Composition

Membrane dynamics in autophagosome biogenesis

Organelle size control – increasing vacuole content activates SNAREs to augment organelle volume through homotypic fusion

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