Spontaneous Transfer of Lipids between Membranes

Brown, Rhoderick E.

doi:10.1007/978-1-4899-1621-1_11

Cited by 15 publications

(7 citation statements)

References 162 publications

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“…POPC and DHPC were selected to favorably accommodate BODIPY-labeled SL and C 18 -DiI. ,, As shown in Figure A, SL-donor and -acceptor model membranes formed by dilution of 0.5 q -value mixtures support robust SL transfer. Notably, almost no increase in BODIPY-SL emission occurs until transfer protein is added, confirming very slow spontaneous SL migration to acceptors in agreement with earlier findings involving conventionally prepared membrane vesicles. − Also, combining SL-donors with only protein fails to significantly increase BODIPY-SL emission unless followed by addition of acceptors showing that protein binding of BODIPY-SL does not explain the FRET response. Rather, the low “catalytic” amounts of GLTP act in “shuttle-like” fashion to transfer Me 4 -BODIPY-GalCer continuously from the SL-donors to the excess acceptors until dynamic equilibrium is approached (∼20 min).…”

Section: Resultssupporting

confidence: 87%

“…Interestingly, fast spontaneous lipid transfer via collisions among polymer-bounded nanodiscs has also recently been reported in agreement with transfer mechanisms reported for bilayer vesicles at high concentrations over three decades ago. , Lowering the lipid model membrane concentrations or adding small amounts of charged lipid mitigates the model membrane collisional contacts and vastly reduces the rate of nonspecific spontaneous lipid transfer. , In recent studies of DMPC/DHPC or DPPC/DHPC bicelles containing 5 mol % of negatively charged phosphatidylglycerol, , the spontaneous transfer rates for the DMPC or DPPC bicelle bilayer-matrix lipid were slow and with their half-times differing from several hours to hundreds of hours, respectively, in agreement with earlier bilayer vesicles studies. The findings suggest a solubility-driven exchange via lipid monomer transfer through the aqueous medium, in agreement with studies of conventional bilayer vesicles , and lipoprotein nanodiscs …”

Section: Discussionsupporting

confidence: 74%

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Measuring Lipid Transfer Protein Activity Using Bicelle-Dilution Model Membranes

Gao

Zhai

et al. 2020

Anal. Chem.

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In vitro assessment of lipid intermembrane transfer activity by cellular proteins typically involves measurement of either radiolabeled or fluorescently labeled lipid trafficking between vesicle model membranes. Use of bilayer vesicles in lipid transfer assays usually comes with inherent challenges because of complexities associated with the preparation of vesicles and their rather short “shelf life”. Such issues necessitate the laborious task of fresh vesicle preparation to achieve lipid transfer assays of high quality, precision, and reproducibility. To overcome these limitations, we have assessed model membrane generation by bicelle dilution for monitoring the transfer rates and specificity of various BODIPY-labeled sphingolipids by different glycolipid transfer protein (GLTP) superfamily members using a sensitive fluorescence resonance energy transfer approach. Robust, protein-selective sphingolipid transfer is observed using donor and acceptor model membranes generated by dilution of 0.5 q-value mixtures. The sphingolipid transfer rates are comparable to those observed between small bilayer vesicles produced by sonication or ethanol injection. Among the notable advantages of using bicelle-generated model membranes are (i) easy and straightforward preparation by means that avoid lipid fluorophore degradation and (ii) long “shelf life” after production (≥6 days) and resilience to freeze–thaw storage. The bicelle-dilution-based assay is sufficiently robust, sensitive, and stable for application, not only to purified LTPs but also for LTP activity detection in crude cytosolic fractions of cell homogenates.

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Section: Resultssupporting

confidence: 87%

Section: Discussionsupporting

confidence: 74%

Measuring Lipid Transfer Protein Activity Using Bicelle-Dilution Model Membranes

Gao

Zhai

et al. 2020

Anal. Chem.

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“…Excitation of AV- (370 nm) or BODIPY-sphingolipid (460 nm) results in minimal emission at 415 nm or 503 nm, respectively due to resonance energy transfer to nearby Per-PC or C18-DiI, respectively. Addition of approximately tenfold excess of sonicated POPC acceptor vesicles or POPC/DHPC bicelles produces little change in fluorescence signal, yielding a “no protein” baseline response for spontaneously transferred AV-sphingolipid, which is very slow ( 83 , 84 ). Protein addition triggers a sudden, hyperbolic increase in AV or BODIPY emission intensity (415 nm or 503 nm, respectively) reflecting the FRET decrease due to protein transport of fluorescent sphingolipid to receiver (acceptor) vesicles and separation from nontransferable Per-PC or C18-DiI lipids in sphingolipid-source vesicles.…”

Section: Methodsmentioning

confidence: 99%

Ceramide-1-phosphate transfer protein (CPTP) regulation by phosphoinositides

Gao

Zhai

Болдырев

et al. 2021

Journal of Biological Chemistry

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Ceramide-1-phosphate transfer proteins (CPTPs) are members of the glycolipid transfer protein (GLTP) superfamily that shuttle ceramide-1-phosphate (C1P) between membranes. CPTPs regulate cellular sphingolipid homeostasis in ways that impact programmed cell death and inflammation. CPTP downregulation specifically alters C1P levels in the plasma and trans -Golgi membranes, stimulating proinflammatory eicosanoid production and autophagy-dependent inflammasome-mediated cytokine release. However, the mechanisms used by CPTP to target the trans -Golgi and plasma membrane are not well understood. Here, we monitored C1P intervesicular transfer using fluorescence energy transfer (FRET) and showed that certain phosphoinositides (phosphatidylinositol 4,5 bisphosphate (PI-(4,5)P 2 ) and phosphatidylinositol 4-phosphate (PI-4P)) increased CPTP transfer activity, whereas others (phosphatidylinositol 3-phosphate (PI-3P) and PI) did not. PIPs that stimulated CPTP did not stimulate GLTP, another superfamily member. Short-chain PI-(4,5)P 2, which is soluble and does not remain membrane-embedded, failed to activate CPTP. CPTP stimulation by physiologically relevant PI-(4,5)P 2 levels surpassed that of phosphatidylserine (PS), the only known non-PIP stimulator of CPTP, despite PI-(4,5)P 2 increasing membrane equilibrium binding affinity less effectively than PS. Functional mapping of mutations that led to altered FRET lipid transfer and assessment of CPTP membrane interaction by surface plasmon resonance indicated that di-arginine motifs located in the α-6 helix and the α3-α4 helix regulatory loop of the membrane-interaction region serve as PI-(4,5)P 2 headgroup-specific interaction sites. Haddock modeling revealed specific interactions involving the PI-(4,5)P 2 headgroup that left the acyl chains oriented favorably for membrane embedding. We propose that PI-(4,5)P 2 interaction sites enhance CPTP activity by serving as preferred membrane targeting/docking sites that favorably orient the protein for function.

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“…This technique made possible the visualization the movement and distribution of labelled lipid molecules in living cells (Pagano & Sleight, 1985). As for lipid transfer or exchange, there is a lack of a unifying mechanism and three different routes are possible: (1) transport of lipids by endocytosis and vesicle membrane flow; (2) energy‐dependent or independent transport of lipid molecules by special carrier‐proteins; and (3) spontaneous transport of lipid monomers by diffusion or by direct contact due to cell organelle collision (Brown, 1990).…”

Section: Introductionmentioning

confidence: 99%

“…Choline‐containing molecules move spontaneously from the exterior medium to the outer layer of the plasma membrane (Sleight & Pagano, 1984) but, because of the absence of specific ATPases with translocase activity, it moves from the cell surface to internal compartments by endocytosis (Voelker, 1990). Conversely, the aminophospholipids are moved from the exoplasmic to the cytoplasmic portion of the membrane bilayer by lipid translocators, named flippases, and reach the different compartments either by binding to the so‐called phospholipid transfer proteins or by spontaneous diffusion through the cytoplasm in an energy‐independent way (Brown, 1990; Cleves et al ., 1991).…”

Section: Introductionmentioning

confidence: 99%

Mapping cholesteryl ester analogue uptake and intracellular flow in Paramecium by confocal fluorescence microscopy

Ramoino

Fronte

Fato

et al. 2002

Journal of Microscopy

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SummaryIn Paramecium primaurelia the uptake and intracellular flow of cholesteryl ester was studied by fluorescence confocal laser scanning optical microscopy and by the fluorescent analogue cholesteryl-BODIPY ® FL C 12 (BODIPY-CE). The BODIPY FL fluorophore has the characteristic of emitting green fluorescence, which is red-shifted as the probe concentrates. In cells incubated with 25 µ m BODIPY-CE for 30 s, fluorescence is found in vesicles located around the cytopharynx in the posterior half of the cell. Successively, the lipid is internalized by food vacuoles, the fluorescent vesicles are distributed throughout the cell and the intracellular membranes are labelled. The food vacuole number is maximum after 10-15 min of continuous labelling, then it decreases until no food vacuoles are found in 30-min fed cells. BODIPY-CE accumulates in red-labelled cytoplasmic droplets located in the anterior half of the cell. When food vacuole formation is inhibited by trifluoperazine, fluorescence is found on cellular membranes and in small green-labelled vesicles at the apical pole. The inhibition of clathrin-mediated endocytosis does not interfere in P. primaurelia with BODIPY-CE intracellular flow: intracellular membranes and storage droplets in the cell anterior part are dyed. Conversely, the use of sterol-binding drugs prevents the lipid accumulation in droplets, stopping the lipid within the cytoplasmic membranes. Furthermore, the cells treated with monensin and cytochalasin B show a labelling of the cellular membranes and lipid droplets, whereas NH 4 Cl reduces the lipid storage. Low temperature (4 ° C) does not prevent the internalization of BODIPY-CE that, however, is localized at the cytoplasmic membrane level and does not accumulate in storage droplets. In addition, BODIPY-CE inhibits phagocytosis, as evidenced by comparing the kinetics of food vacuole formation of control cells, only fed with latex particles, with that of cells fed with latex particles and BODIPY-CE. In conclusion, this study points out that in P. primaurelia the cholesteryl ester enters the cell via food vacuoles and through the plasma membrane and, inside the cell, it alters cell functions.

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Spontaneous Transfer of Lipids between Membranes

Cited by 15 publications

References 162 publications

Measuring Lipid Transfer Protein Activity Using Bicelle-Dilution Model Membranes

Measuring Lipid Transfer Protein Activity Using Bicelle-Dilution Model Membranes

Ceramide-1-phosphate transfer protein (CPTP) regulation by phosphoinositides

Mapping cholesteryl ester analogue uptake and intracellular flow in Paramecium by confocal fluorescence microscopy

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