Lipids are known to play a crucial role both in the normal control of insulin release and in the deterioration of β-cell function, as observed in type 2 diabetes. Despite this established dual role of lipids, little is known about lipid storage and handling in β-cells. Here, we isolated lipid ...

The transmissible spongiform encephalopathies, more commonly known as the prion diseases, are associated with the production and aggregation of disease-related isoforms of the prion protein (PrPSc). The mechanisms by which PrPSc accumulation causes neurodegeneration in these diseases are poorly understood. In cultured neurons the addition of PrPSc alters cell membranes, ...

The balance between protein and lipid biosynthesis and their eventual degradation is a critical component of cellular health. Autophagy, the catabolic process by which cytoplasmic components become degraded in lysosomes, can be induced by various physiological stimuli to maintain cellular homeostasis. Autophagy was for a long time considered a non-selective ...

Plasma membrane proteins and lipids organize into lateral domains of specific composition. Domain formation is achieved by a combination of lipid-lipid and lipid-protein interactions, membrane-binding protein scaffolds and protein fences. The resulting domains function in membrane protein turnover and homeostasis, as well as in cell signaling. We review the mechanisms ...

Many green algal species can accumulate large amounts of triacylglycerides (TAG) under nutrient deprivation, making them a potential source for production of biodiesel. TAG are organized in cytoplasmic lipid bodies, which contain a major lipid droplet protein termed MLDP. Green algae MLDP differ in sequence from plant oleosins and from ...

Skeletonized zirconium phosphonate surfaces are used to support planar lipid bilayers and are shown to be viable substrates for studying transmembrane proteins. The skeletonized surfaces provide space between the bilayer and the solid support to enable protein insertion and avoid denaturation. The skeletonized zirconium octadecylphosphonate surfaces were prepared using Langmuir-Blodgett ...

The lipid droplets (LDs) are intracellular organelles mainly dedicated to the storage and provision of fatty acids. To accomplish these functions the LDs interact with other organelles and cytosolic proteins. In order to explore possible correlations between the physiological states of cells and the protein composition of LDs we have ...

Macroautophagy is an intracellular degradation system, by which cytoplasmic materials are enclosed by the autophagosome and delivered to the lysosome. Autophagosome formation is considered to take place on the endoplasmic reticulum and involves functions of autophagy-related (Atg) proteins. Here, we report the identification and characterization of mammalian Atg2 homologs, Atg2A ...

Detailed investigations of membrane protein folding present a number of serious technical challenges. Most studies addressing this subject have emphasized aspects of protein amino acid sequence and structure. While it is generally accepted that the interplay between proteins and lipids plays an important role in membrane protein folding, the role(s) ...

Formation of covalent protein adducts by lipid electrophiles contributes to diseases and toxicities linked to oxidative stress, but analysis of the adducts presents a challenging analytical problem. We describe selective adduct capture using biotin affinity probes to enrich protein and peptide adducts for analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). ...

In recent years, the functional roles of effectors from a wide variety of fungal and oomycete pathogens have begun to emerge. As a product of this work, the importance of effector-lipid interactions has been made apparent. Phospholipids are not only important signaling molecules, but they also play important roles in ...

Membrane proteins (MPs) play a critical role in many physiological processes such as pumping specific molecules across the otherwise impermeable membrane bilayer that surrounds all cells and organelles. Alterations in the function of MPs result in many human diseases and disorders; thus, an intricate understanding of their structures remains a ...

In eukaryotic cells, the trans-Golgi network serves as a sorting station for post-Golgi traffic. In addition to coat- and adaptor-mediated mechanisms, studies in mammalian epithelial cells and yeast have provided evidence for lipid-dependent protein sorting as a major delivery mechanism for cargo sorting to the cell surface. The mechanism for ...

A detailed understanding of biomembrane architecture is still a challenging task. Many in vitro studies have shown lipid domains but much less information is known about the lateral organization of membrane proteins because their hydrophobic nature limits the use of many experimental methods. We examined lipid domain formation in biomimetic ...

ABSTRACT: BACKGROUND: Protein-lipid interactions play essential roles in the conformational stability and biological functions of membrane proteins. However, few of the previous computational studies have taken into account the atomic details of protein-lipid interactions explicitly. RESULTS: To gain an insight into the molecular mechanisms of the recognition of lipid molecules ...

Abstract Aim: This study investigated the effect of smoking, mother's age, body mass index (BMI), and parity number on density, lipids, proteins, and secreted immunoglobulin A (SIgA) of human milk. Methods: Transitional and mature milk samples were collected from 23 nursing smoker mothers and 43 nursing nonsmoker mothers. Proteins, lipids, ...

The endoplasmic reticulum (ER) plays a crucial role in protein folding, assembly, and secretion. Disruption of ER homeostasis may lead to accumulation of misfolded or unfolded proteins in the ER lumen, a condition referred to as ER stress. In response to ER stress, a signal transduction pathway known as the ...

Many signalling proteins such as the members of the Ras superfamily of GTPases are posttranslationally modified by covalent attachment of lipid groups, which is crucial for the correct localization and function of these proteins. Numerous lipidated proteins are oncogens found often mutated in several human cancers. Therefore, several therapeutic strategies ...

Supported lipid bilayer (SLB) has been demonstrated as a model of cell membranes with prospective bioanalytical or biotechnological applications. In this study, the formation of SLB and their potential biofunctionality against protein adsorption were investigated by Dual Polarization Interferometry (DPI) and Capillary Electrophoresis (CE). DPI studies on different formulations of ...

The mitochondrial outer membrane (OM) contains signal-anchored proteins that bear at their N-terminus a single hydrophobic segment that serves as both a mitochondrial targeting signal and an anchor at the membrane. These proteins, like the vast majority of mitochondrial proteins, are encoded in the nucleus and have to be imported ...

BACKGROUND: Rice embryo is concentrated with lipid, protein and some bioactive chemicals. Two rice mutants IR64-GE and TNG71-GE (M7 generation) were characterised by an enlarged embryo compared with their wild types. In the present study, distributions of protein, lipid, total phenolics, γ-oryzanol, tocols and some essential minerals in these two ...

Highly ordered ring-like structures are formed via the directed assembly of lipid domains in supported bilayers, using the extracellular matrix protein fibronectin. The ability of biological molecules to guide nanoscale assembly suggests potential biomimetic approaches to nanoscale structures.

Integral membrane proteins are challenging to work with biochemically given their insoluble nature; the Nanodisc circumvents the difficulty by stabilizing them in small patches of lipid bilayer. Here, we show that Nanodiscs, when combined with SILAC-based quantitative proteomics, can be used to identify the soluble interacting partners of virtually any ...

Several proteins that play key roles in cholesterol synthesis, regulation, trafficking and signaling are united by sharing the phylogenetically conserved 'sterol-sensing domain' (SSD). The intracellular parasite Toxoplasma possesses at least one gene coding for a protein containing the canonical SSD. We investigated the role of this protein to provide information ...

Membrane proteins that bind and transport lipids face special challenges. Since lipids typically have low water solubility, both accessibility of the substrate to the protein and delivery to the desired destination are problematical. The amphipathic nature of membrane lipids, and their relatively large molecular size, also means that these proteins ...

Prion protein is considered to have an infectious ability by itself. However, in order to explain the main features of prion diseases, additional cofactors would be required. Sanghera et al. (in this issue of Chemistry and Biology) have found evidence that a ganglioside, GM1, is a ligand for the C-terminal region ...

For inner mitochondrial membrane (IMM) proteins that do not undergo N-terminal cleavage, their activity may occur in the absence of a receptor present in the mitochondrial membrane. One such protein is human 3-beta hydroxysteroid dehydrogenase-2 (3βHSD2), the IMM resident protein responsible for catalyzing two key steps in steroid metabolism: the ...

Fattening up: Artificially constructed lipid-protein conjugates can be used to control protein activity and localization at either biological or artificial membrane interfaces. Here, we report a facile technique for the lipid modification of proteins catalyzed by microbial transglutaminase (MTG). MTG-mediated protein lipidation proceeded efficiently without perturbing protein functionality.

Lipid peroxidation generates reactive aldehydes, most notably hydroxynonenal (HNE), which covalently bind amino acid residue side chains leading to protein inactivation and insolubility. Specific adducts of lipid peroxidation have been demonstrated in intimate association with the pathological lesions of Alzheimer disease (AD), suggesting that oxidative stress is a major component ...

Proteins which translocate across cell membranes need to overcome a significant hydrophobic barrier. This is usually accomplished via specialised protein complexes which provide a polar transmembrane pore. Exceptions to this include bacterial toxins which insert into and cross the lipid bilayer itself. We are studying the mechanism by which large ...

This paper describes a method to create giant protein vesicles (GPVs) of ≥10 μm by solvent-driven fusion of large vesicles (0.1-0.2 μm) with reconstituted membrane proteins. We found that formation of GPVs proceeded from rotational mixing of protein-reconstituted large unilamellar vesicles (LUVs) with a lipid-containing solvent phase. We made GPVs ...

ABSTRACT: BACKGROUND: One of the well-defined and characterized protein modifications usually produced by oxidation is carbonylation, an irreversible non-enzymatic modification of proteins. However, carbonyl groups can be introduced into proteins by non-oxidative mechanisms. Reactive carbonyl compounds have been observed to have increased in patients with renal failure. In the present ...

The PAT family of lipid storage droplet proteins comprised five members, each of which has become an established regulator of cellular neutral lipid metabolism. Perilipin 5 (also known as lsdp-5, MLDP, PAT-1, and OXPAT), the most recently discovered member of the family, has been shown to localize to two distinct ...

The influence of the lipid environment on the function of membrane proteins is increasingly recognized as crucial. Nevertheless, the molecular mechanisms underlying protein-lipid interactions remain obscure. Membrane lipid composition has a regulatory effect on membrane protein activity, and for a number of membrane proteins a clear correlation was found between ...

ABSTRACT: The proteins of flotillin-1 and flotillin-2 were originally discovered in axon regeneration of goldfish retinal ganglion cells. They are generally used as marker proteins of lipid rafts and considered to be scaffolding proteins of lipid microdomains. Although they are ubiquitously expressed and well-conserved from fly to man, their exact ...

The mitochondria-associated membrane (MAM) is a sub-region of the endoplasmic reticulum (ER) that facilitates crosstalk between the ER and mitochondria. The MAM actively influences vital cellular processes including Ca(2+) signaling and protein folding. Detergent-resistant microdomains (DRMs) may localize proteins to the mitochondria/MAM interface to coordinate these events. However, the protein ...

Lipid domain formation induced by annexin was investigated in mixtures of phosphatidylcholine (PC), phosphatidylserine (PS), and cholesterol (Chol), which were selected to mimic the inner leaflet of a eukaryotic plasma membrane. Annexins are ubiquitous and abundant cytoplasmic, peripheral proteins, which bind to membranes containing PS in the presence of calcium ...

Lipids, proteins and DNA in the central nervous system have a high sensitivity to oxidative stress. Reactive oxygen species (ROS)-induced damage increases with aging, especially in the last quarter of the life span. The so called base level of oxidative modification of lipids could be important to cell signaling, and ...

Exosomes are membraneous nanovesicles of endocytic origin released by most cell types from diverse organisms; they play a critical role in cell-cell communication. ExoCarta (http://www.exocarta.org) is a manually curated database of exosomal proteins, RNA and lipids. The database catalogs information from both published and unpublished exosomal studies. The mode of ...

The activities of many mammalian membrane proteins including G-protein coupled receptors are cholesterol-dependent. Unlike higher eukaryotes, yeast do not make cholesterol. Rather they make a related molecule called ergosterol. As cholesterol and ergosterol are biologically non-equivalent, the potential of yeast as hosts for overproducing mammalian membrane proteins has never been ...

Anodic aluminum oxide (AAO) substrates with aligned, cylindrical, non-intersecting pores with diameters of 75nm and depths of 3.5 or 10μm were functionalized with lipid monolayers harboring different receptor lipids. AAO was first functionalized with dodecyl-trichlorosilane, followed by fusion of small unilamellar vesicles (SUVs) forming a lipid monolayer. The SUVs' lipid ...

Lipid rafts are specific microdomains of plasma membrane which are enriched in cholesterol and sphingolipids. These domains seem to favour the interactions of particular proteins and the regulation of signalling pathways in the cells. Recent data have shown that among the proteins, which are preferentially localized in lipid rafts, are ...

Lipid transfer proteins of the steroidogenic acute regulatory protein (StAR)-related lipid-transfer (START) domain family are defined by the presence of a conserved ~210 amino acid sequence that folds into an α/β helix-grip structure forming a hydrophobic pocket for ligand binding. The mammalian START proteins bind diverse ligands: cholesterol, oxysterols, phospholipids, ...

Dehydroepiandrosterone (DHEA) is a precursor of the adrenocorticosteroid hormones that are common to all animals, including poultry. The study described herein was undertaken to investigate the effect of DHEA on lipid metabolism in broiler chickens during embryonic development and to determine the regulatory mechanisms involved in its physiological action. Treatment ...

Caudal autotomy, or voluntary self-amputation of the tail, is a common and effective predator evasion mechanism used by most lizard species. The tail contributes to a multitude of biological functions such as locomotion, energetics, and social interactions, and thus there are often costs associated with autotomy. Notably, relatively little is ...

Japanese encephalitis virus (JEV) is an enveloped flavivirus and the most common agent of viral encephalitis that enter cells through receptor-mediated endocytosis and low pH-triggered membrane fusion. Although lipid rafts, cholesterol-enriched lipid-ordered membrane domains, have been shown to participate in JEV entry, the mechanisms of the early events of JEV ...

We provide an overview of lipid-dependent polytopic membrane protein folding and topogenesis. Lipid dependence of this process was determined by employing Escherichia coli cells in which specific lipids can be eliminated, substituted, tightly titrated or controlled temporally during membrane protein synthesis and assembly. The secondary transport protein lactose permease (LacY) ...

The CD1 family consists of five proteins that are related to the peptide-presenting MHC class I family. T cells can recognize the presentation of both foreign- and self-derived lipids on four CD1 family members. The identities of the self-lipids capable of stimulating autoreactive T cell responses remain elusive or controversial. ...

Oil bodies are sites of energy and carbon storage in many organisms including microalgae. As a step toward deciphering oil accumulation mechanisms in algae, we used proteomics to analyze purified oil bodies from the model microalga Chlamydomonas reinhardtii grown under nitrogen deprivation. Among the 248 proteins (≥2 peptides) identified by ...

The indolines and thionins are basic, amphiphilic and cysteine-rich proteins found in cereals; puroindoline-a (Pin-a) and β-purothionin (β-Pth) are members of these families in wheat (Triticum aestivum). Pin-a and β-Pth have been suggested to play a significant role in seed defence against microbial pathogens, making the interaction of these proteins ...