Mapping the electrostatic profiles of cellular membranes

Eisenberg, Sharon; Haimov, Ehud; Walpole, Glenn F. W.; Plumb, Jonathan; Kozlov, Michael M.; Grinstein, Sergio

doi:10.1091/mbc.e19-08-0436

Cited by 27 publications

(19 citation statements)

References 26 publications

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“…Reasoning that, with respect to charge, the decreases in the four predominant anionic phospholipids would more than offset any increases in PIP3, we sought to measure spatiotemporal changes in membrane surface charge. We started with a generic membrane surface charge sensor, R(+8)-Pre, which had been quantitatively characterized in vitro (by liposome binding assays) to detect the combination of anionic lipids 22, 30, 54 . Consistent with our observations of the individual lipids, we found that the back-state regions of cortical waves in Dictyostelium cells are defined by high negative surface charge whereas the front-state regions shun the charge sensor (Figure 2A; Video S4).…”

Section: Resultsmentioning

confidence: 99%

“…Relatively few studies have focused on the role of membrane surface charge itself 21, 29 . These have proposed that the zeta potential, in the range of −20 to −50 mV 30–32 , acts in regulating local pH and soluble second messenger concentrations, altering ion channel conductance, and controlling the association of peripheral membrane proteins 21–24, 33–36 . It was also shown that the during immune synapse formation and phagocytosis, the membrane surface charge changes 22, 37–39 .…”

Section: Introductionmentioning

confidence: 99%

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Spatiotemporal dynamics of membrane surface charge regulates cell polarity and migration

Banerjee

Biswas

Pal

et al. 2022

Preprint

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During cell migration and polarization, hundreds of signal transduction and cytoskeletal components self-organize to generate localized protrusions. Although biochemical and genetic analyses have delineated many specific interactions, how the activation and localization of so many different molecules are spatiotemporally orchestrated at the subcellular level has remained unclear. Here we show that the regulation of negative surface charge on the inner leaflet of the plasma membrane plays an integrative role in the molecular interactions. Surface charge, or zeta potential, is transiently lowered at new protrusions and within cortical waves of Ras/PI3K/TORC2/F-actin network activation. Rapid alterations of inner leaflet anionic phospholipids, such as PI(4,5)P2, PI(3,4)P2, phosphatidylserine, and phosphatidic acid, collectively contribute to the surface charge changes. Abruptly reducing the surface charge by recruiting positively charged optogenetic actuators was sufficient to trigger the entire biochemical network, initiate de novo protrusions, and abrogate pre-existing polarity. These effects were blocked by genetic or pharmacological inhibitions of key signaling components such as Akt and PI3K/TORC2. Conversely, increasing the negative surface deactivated the network and locally suppressed chemoattractant-induced protrusions or subverted EGF-induced ERK activation. Computational simulations involving excitable biochemical networks demonstrated that slight changes in feedback loops, induced by recruitment of the actuators, could lead to outsized effects on system activation. We propose that key signaling network components act on, and are in turn acted upon, by surface charge, closing feedback loops which bring about the global-scale molecular self-organization required for spontaneous protrusion formation, cell migration, and polarity establishment.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatiotemporal dynamics of membrane surface charge regulates cell polarity and migration

Banerjee

Biswas

Pal

et al. 2022

Preprint

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“…This yield is more than three times higher than the yield from ULGT agarose, HGT agarose, and PVA. This result is notable since ULGT agarose and PVA, both used extensively in the literature [32][33][34][35][36][37][38][39][40] , produce significantly lower yields of GUVs in PBS compared to LGT agarose. ULGT and LGT agaroses with different catalog numbers showed similar yields to those shown in Figure 2 (Figure S4).…”

Section: Low Gelling Temperature Agarose Produces the Highest Yield O...mentioning

confidence: 99%

Osmotic pressure enables high yield assembly of giant vesicles in solutions of physiological ionic strengths

Cooper

Girish

Subramaniam

2022

Preprint

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Giant unilamellar vesicles (GUVs) are micrometer scale minimal cellular mimics that are useful for synthetic biology and drug delivery. However, their assembly in solutions with ionic concentrations of 100-150 mM Na/KCl (salty solutions) is challenging. Here, we investigate quantitatively the effects of temperature and chemical identity of small molecule compounds and macromolecular polymers on the molar yields of GUVs using high resolution confocal microscopy and large dataset image analysis. The macromolecular polymer low gelling temperature agarose is the singular compound that is effective in producing high yields of GUVs in salty solutions. We propose a free-energy model of budding to explain the effects of polymers in assisting the assembly of GUVs. Experimental data obtained by modulating the ionic strength of the solution support our model's prediction that the osmotic pressure of dissolving polymers results in a net reduction in the free energy for bud formation. The uncovered mechanistic insight provides a quantitative experimental and theoretical framework to guide future studies and shows a facile means for obtaining GUVs in solutions of physiological ionic strengths.

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“…The idea of localisation controlling the function and activity of PM resident proteins is well-established (Eisenberg et al, 2021; Kusumi et al, 2005, 2010, 2011; Trimble and Grinstein, 2015). Our work provides a link between EFR3 (and PI4K-IIIα) and insulin-stimulated glucose transport, establishing EFR3 as a key locus of insulin action.…”

Section: Discussionmentioning

confidence: 99%

EFR3 and phosphatidylinositol 4-kinase IIIα regulate insulin-stimulated glucose transport and GLUT4 dispersal in 3T3-L1 adipocytes

Koester

Laidlaw

Morris

et al. 2021

Preprint

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Insulin stimulates glucose transport in muscle and adipocytes. This is achieved by regulated delivery of intracellular glucose transporter (GLUT4)-containing vesicles to the plasma membrane where they dock and fuse, resulting in increased cell surface GLUT4 levels. Recent work identified a potential further regulatory step, in which insulin increases the dispersal of GLUT4 in the plasma membrane away from the sites of vesicle fusion. EFR3 is a scaffold protein that facilitates localisation of phosphatidylinositol 4-kinase type IIIα to the cell surface. Here we show that knockdown of EFR3 or phosphatidylinositol 4-kinase type IIIα impairs insulin-stimulated glucose transport in adipocytes. Using direct stochastic reconstruction microscopy, we also show that EFR3 knockdown impairs insulin stimulated GLUT4 dispersal in the plasma membrane. We propose that EFR3 plays a previously unidentified role in controlling insulin-stimulated glucose transport by facilitating dispersal of GLUT4 within the plasma membrane.

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Mapping the electrostatic profiles of cellular membranes

Cited by 27 publications

References 26 publications

Spatiotemporal dynamics of membrane surface charge regulates cell polarity and migration

Spatiotemporal dynamics of membrane surface charge regulates cell polarity and migration

Osmotic pressure enables high yield assembly of giant vesicles in solutions of physiological ionic strengths

EFR3 and phosphatidylinositol 4-kinase IIIα regulate insulin-stimulated glucose transport and GLUT4 dispersal in 3T3-L1 adipocytes

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