Browse
Submit Data
Databases
API
Help

Dataset Information

24 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Caveolin-1 Endows Order in Cholesterol-Rich Detergent Resistant Membranes.

ABSTRACT: Cholesterol-enriched functional portions of plasma membranes, such as caveolae and rafts, were isolated from lungs of wild-type (WT) and caveolin-1 knockout (Cav-1 KO) mice within detergent resistant membranes (DRMs). To gain insight into their molecular composition we performed proteomic and lipid analysis on WT and Cav-1 KO-DRMs that showed predicted variations of proteomic profiles and negligible differences in lipid composition, while Langmuir monolayer technique and small and wide-angle X-ray scattering (SAXS-WAXS) were here originally introduced to study DRMs biophysical association state. Langmuir analysis of Cav-1 containing DRMs displayed an isotherm with a clear-cut feature, suggesting the coexistence of the liquid-ordered (L_o) phase typical of the raft structure, namely "cholesterol-rich L_o phase," with a phase fully missing in Cav-1 KO that we named "caveolin-induced L_o phase." Furthermore, while the sole lipid component of both WT and KO-DRMs showed qualitatively similar isotherm configuration, the reinsertion of recombinant Cav-1 into WT-DRMs lipids restored the WT-DRM pattern. X-ray diffraction results confirmed that Cav-1 causes the formation of a "caveolin-induced L_o phase," as suggested by Langmuir experiments, allowing us to speculate about a possible structural model. These results show that the unique molecular link between Cav-1 and cholesterol can spur functional order in a lipid bilayer strictly derived from biological sources.

SUBMITTER: Raggi C

PROVIDER: S-EPMC6680987 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Structural characterization of the caveolin scaffolding domain in association with cholesterol-rich membranes.

Project description:Members of the caveolin protein family are implicated in the formation of caveolae and play important roles in a number of signaling pathways and in the regulation of various proteins. We employ complementary spectroscopic methods to study the structure of the caveolin scaffolding domain (CSD) in caveolin-1 fragments, while bound to cholesterol-rich membranes. This key domain is thought to be involved in multiple critical functions that include protein recognition, oligomerization, and cholesterol binding. In our membrane-bound peptides, residues within the flanking intramembrane domain (IMD) are found to adopt an α-helical structure, consistent with its commonly believed helical hairpin conformation. Intriguingly, in these same peptides, we observe a β-stranded conformation for residues in the CSD, contrasting with earlier reports, which commonly do not reflect β-structure. Our experimental data based on solid-state NMR, CD, and FTIR are found to be consistent with computational analyses of the secondary structure preference of the primary sequence. We discuss how our structural data of membrane binding Cav fragments may match certain general features of cholesterol-binding domains and could be consistent with the role for CSD in protein recognition and homo-oligomerization.

| S-EPMC3290515 | biostudies-literature

Omega 3 fatty acids chemosensitize multidrug resistant colon cancer cells by down-regulating cholesterol synthesis and altering detergent resistant membranes composition.

Project description:BackgroundThe activity of P-glycoprotein (Pgp) and multidrug resistance related protein 1 (MRP1), two membrane transporters involved in multidrug resistance of colon cancer, is increased by high amounts of cholesterol in plasma membrane and detergent resistant membranes (DRMs). It has never been investigated whether omega 3 polyunsatured fatty acids (PUFAs), which modulate cholesterol homeostasis in dyslipidemic syndromes and have chemopreventive effects in colon cancer, may affect the response to chemotherapy in multidrug resistant (MDR) tumors.MethodsWe studied the effect of omega 3 PUFAs docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in human chemosensitive colon cancer HT29 cells and in their MDR counterpart, HT29-dx cells.ResultsMDR cells, which overexpressed Pgp and MRP1, had a dysregulated cholesterol metabolism, due to the lower expression of ubiquitin E3 ligase Trc8: this produced lower ubiquitination rate of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCoAR), higher cholesterol synthesis, higher cholesterol content in MDR cells. We found that DHA and EPA re-activated Trc8 E3 ligase in MDR cells, restored the ubiquitination rate of HMGCoAR to levels comparable with chemosensitive cells, reduced the cholesterol synthesis and incorporation in DRMs. Omega 3 PUFAs were incorporated in whole lipids as well as in DRMs of MDR cells, and altered the lipid composition of these compartments. They reduced the amount of Pgp and MRP1 contained in DRMs, decreased the transporters activity, restored the antitumor effects of different chemotherapeutic drugs, restored a proper tumor-immune system recognition in response to chemotherapy in MDR cells.ConclusionsOur work describes a new biochemical effect of omega 3 PUFAs, which can be useful to overcome chemoresistance in MDR colon cancer cells.

| S-EPMC4225767 | biostudies-literature

Proteomic analysis of Escherichia coli detergent-resistant membranes (DRM).

Project description:Membrane microdomains or lipid rafts compartmentalize cellular processes by laterally organizing membrane components. Such sub-membrane structures were mainly described in eukaryotic cells, but, recently, also in bacteria. Here, the protein content of lipid rafts in Escherichia coli was explored by mass spectrometry analyses of Detergent Resistant Membranes (DRM). We report that at least three of the four E. coli flotillin homologous proteins were found to reside in DRM, along with 77 more proteins. Moreover, the proteomic data were validated by subcellular localization, using immunoblot assays and fluorescence microscopy of selected proteins. Our results confirm the existence of lipid raft-like microdomains in the inner membrane of E. coli and represent the first comprehensive profiling of proteins in these bacterial membrane platforms.

| S-EPMC6788730 | biostudies-literature

Cholesterol induces specific spatial and orientational order in cholesterol/phospholipid membranes.

Project description:BackgroundIn lipid bilayers, cholesterol facilitates the formation of the liquid-ordered phase and enables the formation of laterally ordered structures such as lipid rafts. While these domains have an important role in a variety of cellular processes, the precise atomic-level mechanisms responsible for cholesterol's specific ordering and packing capability have remained unresolved.Methodology/principal findingsOur atomic-scale molecular dynamics simulations reveal that this ordering and the associated packing effects in membranes largely result from cholesterol's molecular structure, which differentiates cholesterol from other sterols. We find that cholesterol molecules prefer to be located in the second coordination shell, avoiding direct cholesterol-cholesterol contacts, and form a three-fold symmetric arrangement with proximal cholesterol molecules. At larger distances, the lateral three-fold organization is broken by thermal fluctuations. For other sterols having less structural asymmetry, the three-fold arrangement is considerably lost.Conclusions/significanceWe conclude that cholesterol molecules act collectively in lipid membranes. This is the main reason why the liquid-ordered phase only emerges for Chol concentrations well above 10 mol% where the collective self-organization of Chol molecules emerges spontaneously. The collective ordering process requires specific molecular-scale features that explain why different sterols have very different membrane ordering properties: the three-fold symmetry in the Chol-Chol organization arises from the cholesterol off-plane methyl groups allowing the identification of raft-promoting sterols from those that do not promote rafts.

| S-EPMC2887443 | biostudies-literature

Proteomic Profiling of Detergent Resistant Membranes (Lipid Rafts) of Prostasomes.

Project description:Prostasomes are exosomes derived from prostate epithelial cells through exocytosis by multivesicular bodies. Prostasomes have a bilayered membrane and readily interact with sperm. The membrane lipid composition is unusual with a high contribution of sphingomyelin at the expense of phosphatidylcholine and saturated and monounsaturated fatty acids are dominant. Lipid rafts are liquid-ordered domains that are more tightly packed than the surrounding nonraft phase of the bilayer. Lipid rafts are proposed to be highly dynamic, submicroscopic assemblies that float freely within the liquid disordered membrane bilayer and some proteins preferentially partition into the ordered raft domains. We asked the question whether lipid rafts do exist in prostasomes and, if so, which proteins might be associated with them. Prostasomes of density range 1.13-1.19g/ml were subjected to density gradient ultracentrifugation in sucrose fabricated by phosphate buffered saline (PBS) containing 1% Triton X-100 with capacity for banding at 1.10 g/ml, i.e. the classical density of lipid rafts. Prepared prostasomal lipid rafts (by gradient ultracentrifugation) were analyzed by mass spectrometry. The clearly visible band on top of 1.10g/ml sucrose in the Triton X-100 containing gradient was subjected to liquid chromatography-tandem MS and more than 370 lipid raft associated proteins were identified. Several of them were involved in intraluminal vesicle formation, e.g. tetraspanins, ESCRTs, and Ras-related proteins. This is the first comprehensive liquid chromatography-tandem MS profiling of proteins in lipid rafts derived from exosomes. Data are available via ProteomeXchange with identifier PXD002163.

| S-EPMC4638043 | biostudies-literature

Human platelet detergent resistant membranes proteome

Project description:Here we characterized the proteins associated with detergent resistant membranes (DRMs) from resting and activated human platelets. We achieved a proteomic profile of 141 DRM proteins involved in many biological pathways including 'PAR-1-mediated thrombin signal events', 'Integrin family cell surface interactions', 'Platelet activation, signalling and aggregation' and 'Platelet degranulation'. Therefore, a high level of relevant platelet signalling and trafficking proteins were identified e.g., Rap 1b, Src, SNAP-23 and syntaxin-11, implicating platelet DRMs as concentrating platforms not only in the critical platelet function of activation but also in secretion/degranulation.

2017-03-28 | MSV000080708 | MassIVE

Human platelet detergent resistant membranes proteome

2016-06-23 | PXD002554 | Pride

Detergent-resistant membranes in Agrobacterium tumefaciens

Project description:We established a protocol for the biochemical fractionation of Agrobacterium tumefaciens membranes, and characterized the proteome of detergent-sensitive and detergent-resistant membrane fractions by mass spectrometry. We found that well-established microdomain marker proteins co-purify with proteins associated with transport or secretion processes in the detergent-resistant fraction, suggesting a functional micro-compartmentalization of the Gram-negative membrane. The presence of components of virulence-associated secretion systems in detergent-resistant membranes supports the involvement of bacterial microdomains in host-microbe interaction and microbial competition.

2021-11-03 | PXD028782 | Pride

Reversible Dissolution of Microdomains in Detergent-Resistant Membranes at Physiological Temperature.

Project description:The formation of lipid microdomains ("rafts") is presumed to play an important role in various cellular functions, but their nature remains controversial. Here we report on microdomain formation in isolated, detergent-resistant membranes from MDA-MB-231 human breast cancer cells, studied by atomic force microscopy (AFM). Whereas microdomains were readily observed at room temperature, they shrunk in size and mostly disappeared at higher temperatures. This shrinking in microdomain size was accompanied by a gradual reduction of the height difference between the microdomains and the surrounding membrane, consistent with the behaviour expected for lipids that are laterally segregated in liquid ordered and liquid disordered domains. Immunolabeling experiments demonstrated that the microdomains contained flotillin-1, a protein associated with lipid rafts. The microdomains reversibly dissolved and reappeared, respectively, on heating to and cooling below temperatures around 37 °C, which is indicative of radical changes in local membrane order close to physiological temperature.

| S-EPMC4493071 | biostudies-literature

Identification of novel ?-secretase-associated proteins in detergent-resistant membranes from brain.

Project description:In Alzheimer disease, oligomeric amyloid ?-peptide (A?) species lead to synapse loss and neuronal death. ?-Secretase, the transmembrane protease complex that mediates the final catalytic step that liberates A? from its precursor protein (APP), has a multitude of substrates, and therapeutics aimed at reducing A? production should ideally be specific for APP cleavage. It has been shown that APP can be processed in lipid rafts, and ?-secretase-associated proteins can affect A? production. Here, we use a biotinylated inhibitor for affinity purification of ?-secretase and associated proteins and mass spectrometry for identification of the purified proteins, and we identify novel ?-secretase-associated proteins in detergent-resistant membranes from brain. Furthermore, we show by small interfering RNA-mediated knockdown of gene expression that a subset of the ?-secretase-associated proteins, in particular voltage-dependent anion channel 1 (VDAC1) and contactin-associated protein 1 (CNTNAP1), reduced A? production (A?40 and A?42) by around 70%, whereas knockdown of presenilin 1, one of the essential ?-secretase complex components, reduced A? production by 50%. Importantly, these proteins had a less pronounced effect on Notch processing. We conclude that VDAC1 and CNTNAP1 associate with ?-secretase in detergent-resistant membranes and affect APP processing and suggest that molecules that interfere with this interaction could be of therapeutic use for Alzheimer disease.

| S-EPMC3320946 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data