Efficient replacement of plasma membrane outer leaflet phospholipids and sphingolipids in cells with exogenous lipids

Li, Guangtao; Kim, Jihyun; Huang, Zhen; Clair, Johnna R. St.; Brown, Deborah A.; London, Erwin

doi:10.1073/pnas.1610705113

Cited by 81 publications

(118 citation statements)

References 29 publications

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“…5b ). In addition, the inhibitory effect of cell-surface PS was further confirmed by manipulating the cell-surface contents of PS using the methyl-α-cyclodextrin (MαCD)-catalyzed phospholipid exchange method 40 (Fig. 5c, d ).…”

Section: Resultsmentioning

confidence: 90%

Cell surface flip-flop of phosphatidylserine is critical for PIEZO1-mediated myotube formation

et al. 2018

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Myotube formation by fusion of myoblasts and subsequent elongation of the syncytia is essential for skeletal muscle formation. However, molecules that regulate myotube formation remain elusive. Here we identify PIEZO1, a mechanosensitive Ca2+ channel, as a key regulator of myotube formation. During myotube formation, phosphatidylserine, a phospholipid that resides in the inner leaflet of the plasma membrane, is transiently exposed to cell surface and promotes myoblast fusion. We show that cell surface phosphatidylserine inhibits PIEZO1 and that the inward translocation of phosphatidylserine, which is driven by the phospholipid flippase complex of ATP11A and CDC50A, is required for PIEZO1 activation. PIEZO1-mediated Ca2+ influx promotes RhoA/ROCK-mediated actomyosin assemblies at the lateral cortex of myotubes, thus preventing uncontrolled fusion of myotubes and leading to polarized elongation during myotube formation. These results suggest that cell surface flip-flop of phosphatidylserine acts as a molecular switch for PIEZO1 activation that governs proper morphogenesis during myotube formation.

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Section: Resultsmentioning

confidence: 90%

Cell surface flip-flop of phosphatidylserine is critical for PIEZO1-mediated myotube formation

et al. 2018

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“…We therefore hypothesize that enzymes involved in long chain fatty acid activation and elongation are important drivers of lipid oscillations. As very long chain PC and SM lipids make up a significant proportion of the outer leaflet of the plasma membrane (47,48), these data suggest that the circadian clock might impact on plasma membrane function, with important consequences on receptor signaling and membrane glucose uptake.…”

Section: Discussionmentioning

confidence: 89%

Lipidomics reveals diurnal lipid oscillations in human skeletal muscle persisting in cellular myotubes cultured in vitro

Loizides‐Mangold

Perrin

Vandereycken

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Circadian clocks play an important role in lipid homeostasis, with impact on various metabolic diseases. Due to the central role of skeletal muscle in whole-body metabolism, we aimed at studying muscle lipid profiles in a temporal manner. Moreover, it has not been shown whether lipid oscillations in peripheral tissues are driven by diurnal cycles of rest-activity and food intake or are able to persist in vitro in a cell-autonomous manner. To address this, we investigated lipid profiles over 24 h in human skeletal muscle in vivo and in primary human myotubes cultured in vitro. Glycerolipids, glycerophospholipids, and sphingolipids exhibited diurnal oscillations, suggesting a widespread circadian impact on muscle lipid metabolism. Notably, peak levels of lipid accumulation were in phase coherence with core clock gene expression in vivo and in vitro. The percentage of oscillating lipid metabolites was comparable between muscle tissue and cultured myotubes, and temporal lipid profiles correlated with transcript profiles of genes implicated in their biosynthesis. Lipids enriched in the outer leaflet of the plasma membrane oscillated in a highly coordinated manner in vivo and in vitro. Lipid metabolite oscillations were strongly attenuated upon siRNA-mediated clock disruption in human primary myotubes. Taken together, our data suggest an essential role for endogenous cell-autonomous human skeletal muscle oscillators in regulating lipid metabolism independent of external synchronizers, such as physical activity or food intake.lipid metabolism | circadian clock | human skeletal muscle | human primary myotubes | lipidomics C ircadian oscillations are daily cycles in behavior and physiology that are driven by the existence of underlying intrinsic biological clocks with near 24-h periods. This anticipatory mechanism has evolved to ensure that all aspects of behavior and physiology, including metabolic pathways, are temporally coordinated with daily cycles of rest-activity and feeding to provide the organism with an adaptive advantage (1). In mammals, circadian oscillations are driven by a master pacemaker, located in the suprachiasmatic nucleus (SCN) of the hypothalamus, which orchestrates subsidiary oscillators in peripheral organs via neuronal, endocrine, and metabolic signaling pathways (2, 3).Large-scale gene expression datasets suggest that, in mammals, the vast majority of circadian-gene expression is highly organ-specific (4-6). Key metabolic functions in peripheral organs are subject to daily oscillations, such as carbohydrate and lipid metabolism by the liver, skeletal muscle, and endocrine pancreas (7).Skeletal muscle is a major contributor of whole-body metabolism and is the main site of glucose uptake in the postprandial state (8). Therefore, perturbations in glucose sensing and metabolism in skeletal muscle are strongly associated with insulin resistance in type 2 diabetes (T2D) (9). Recent data support a fundamental role for the circadian muscle clock in the regulation of glucose uptake, with a significant re...

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“…The excellent correspondence between the amount of target eliminated and product formed supports the quantitative accuracy of our assay. Although this enzymatic approach cannot evaluate the lipid asymmetry of cells which contain internal membranes, isolated PM lipidomes from such cells (47,48) could be used to predict leaflet lipidomes, relying on the well supported assumption (49,50) that headgroup classes would have similar asymmetries as measured here in…”

Section: Discussionmentioning

confidence: 91%

The mammalian plasma membrane is defined by transmembrane asymmetries in lipid unsaturation, leaflet packing, and protein shape

Lorent

Levental

Ganesan

et al. 2019

Preprint

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A fundamental feature of cellular plasma membranes (PM) is the asymmetric distribution of lipids between the bilayer leaflets. This asymmetry is central to cellular physiology, regulating signaling, apoptosis, coagulation, and cell-cell fusion. While the broad transbilayer distributions of some lipid types are well established, the detailed lipidomic asymmetry of the PM has not been characterized and thus the compositions of the individual leaflets remain poorly understood. Further, how these compositional differences contribute to structural asymmetries between PM leaflets in living cells is not defined. Here, we report the distinct lipidomes and biophysical properties of both monolayers in living mammalian PMs. Using mass spectrometry coupled to enzymatic digestion, we report the detailed compositions of PM leaflets of human erythrocytes. We find a dramatic asymmetry in phospholipid unsaturation, with the cytoplasmic leaflet being ~2-fold more unsaturated than the exoplasmic. Atomistic simulations of lipid mixtures compiled from the lipidomic observations suggested significant asymmetries in lipid order, packing, and dynamics between the two PM leaflets. These were probed directly in the PM of living cells by Fluorescence Lifetime Imaging Microscopy (FLIM) of leaflet-selective, environment-sensitive probes. The outer PM leaflet is highly packed and ordered, resembling a liquid ordered phase, whereas the inner leaflet is significantly more disordered. This biophysical asymmetry is maintained in the endocytic system. These observations reveal the detailed compositional and biophysical asymmetry of mammalian plasma membranes, elucidating fundamental design principles of living membranes. SIGNIFICANCE STATEMENT:The asymmetric distribution of lipids between the two bilayer leaflets is a fundamental feature of mammalian plasma membranes. Here, we quantify the comprehensive lipidomes of the two PM leaflets in living mammalian cells and examine their consequences on leaflet physical properties. Using computer simulations, we predict distinct biophysical features for the two leaflets and confirm these with a variety of spectroscopic and microscopic techniques. We find that the outer leaflet of the membrane contains many more fully saturated lipids, which endows it with higher lipid packing and lower diffusivity.

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Efficient replacement of plasma membrane outer leaflet phospholipids and sphingolipids in cells with exogenous lipids

Cited by 81 publications

References 29 publications

Cell surface flip-flop of phosphatidylserine is critical for PIEZO1-mediated myotube formation

Cell surface flip-flop of phosphatidylserine is critical for PIEZO1-mediated myotube formation

Lipidomics reveals diurnal lipid oscillations in human skeletal muscle persisting in cellular myotubes cultured in vitro

The mammalian plasma membrane is defined by transmembrane asymmetries in lipid unsaturation, leaflet packing, and protein shape

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