Search results for "Lipid rafts"
showing 10 items of 12 documents
Differential Effect of Plant Lipids on Membrane Organization
2015
SPE IPM; International audience; The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger…
Cholesterol Hydroxylating Cytochrome P450 46A1: From Mechanisms of Action to Clinical Applications
2021
Cholesterol, an essential component of the brain, and its local metabolism are involved in many neurodegenerative diseases. The blood-brain barrier is impermeable to cholesterol; hence, cholesterol homeostasis in the central nervous system represents a balance betweenin situbiosynthesis and elimination. Cytochrome P450 46A1 (CYP46A1), a central nervous system-specific enzyme, converts cholesterol to 24-hydroxycholesterol, which can freely cross the blood-brain barrier and be degraded in the liver. By the dual action of initiating cholesterol efflux and activating the cholesterol synthesis pathway, CYP46A1 is the key enzyme that ensures brain cholesterol turnover. In humans and mouse models,…
Comparative lipidomics and proteomics analysis of platelet lipid rafts using different detergents
2016
Lipid rafts play a pivotal role in physiological functions of platelets. Their isolation using nonionic mild detergents is considered as the gold standard method, but there is no consensual detergent for lipid raft studies. We aimed to investigate which detergent is the most suitable for lipid raft isolation from platelet membrane, based on lipidomics and proteomics analysis. Platelets were obtained from healthy donors. Twelve sucrose fractions were extracted by three different detergents, namely Brij 35, Lubrol WX, and Triton X100, at 0.05% and 1%. After lipidomics analysis and determination of fractions enriched in cholesterol (Ch) and sphingomyelin (SM), proteomics analysis was performed…
CD95 DISC formation and internalizzation occur in lipid rafts of typeI and typeII cells
2004
We investigated the membrane localization of CD95 in type I and type II cells, which differ in their ability to recruit and activate caspase-8. We found that CD95 was preferentially located in lipid rafts of type I cells, while it was present both in raft and non-raft plasma membrane sub-domains of type II cells. After stimulation, CD95 located in phospholipid-rich plasma membrane was recruited to lipid rafts in both types of cells. Similarly, CD95 cross-linking resulted in caspase-independent translocation of FADD/MORT1 and caspase-8 to the lipid rafts, which was prevented by a death domain-defective receptor. CD95 internalization was then rapid in type I and delayed in type II cells and s…
Oxysterols: Influence on plasma membrane rafts microdomains and development of ocular diseases
2015
Oxidation of cholesterol into oxysterols is a major way of elimination of cholesterol from the liver and extrahepatic tissues, including the brain and the retina. Oxysterols are involved in various cellular processes. Numerous links have been established between oxysterols and several disorders such as neurodegenerative pathologies, retinopathies and atherosclerosis. Different components of the lipid layer such as sphingolipids, sterols and proteins participate to membrane fluidity and forme lipid rafts microdomains. Few data are available on the links between lipids rafts and oxysterols. The purpose of this review is to suggest the potential role of lipid rafts microdomains in the developm…
Dynamic changes in the subcellular distribution of the tobacco ROS-producing enzyme RBOHD in response to the oomycete elicitor cryptogein.
2014
Highlight text The oomycete elicitor cryptogein triggers the relocation of RBOHD from intracellular compartments to the plasma membrane in tobacco cells. This suggests that intracellular trafficking is a potential determinant of RBOHD activity.
CD95 death-inducing signaling complex formation and internalization occur in lipid rafts of type I and type II cells
2004
We investigated the membrane localization of CD95 in type I and type II cells, which differ in their ability to recruit and activate caspase-8. We found that CD95 was preferentially located in lipid rafts of type I cells, while it was present both in raft and non-raft plasma membrane sub-domains of type II cells. After stimulation, CD95 located in phospholipid-rich plasma membrane was recruited to lipid rafts in both types of cells. Similarly, CD95 cross-linking resulted in caspase-independent translocation of FADD/MORT1 and caspase-8 to the lipid rafts, which was prevented by a death domain-defective receptor. CD95 internalization was then rapid in type I and delayed in type II cells and s…
Cholesterol Dependence of Collagen and Echovirus 1 Trafficking along the Novel α2β1 Integrin Internalization Pathway
2013
We have previously shown that soluble collagen and a human pathogen, echovirus 1 (EV1) cluster α2β1 integrin on the plasma membrane and cause their internalization into cytoplasmic endosomes. Here we show that cholesterol plays a major role not only in the uptake of α2β1 integrin and its ligands but also in the formation of α2 integrin-specific multivesicular bodies (α2-MVBs) and virus infection. EV1 infection and α2β1 integrin internalization were totally halted by low amounts of the cholesterol-aggregating drugs filipin or nystatin. Inhibition of cholesterol synthesis and accumulation of lanosterol after ketoconazole treatment inhibited uptake of collagen, virus and clustered integrin, an…
Plant lipid rafts : from proteic composition to physiological roles
2007
International audience; A large body of evidence supports the existence, in membrane from animal and yeast cells, of functional microdomains playing important roles in protein sorting, signal transduction, or infection by pathogens (1). We demonstrated the presence, in plants, of detergent resistant fractions isolated from plasma membrane, with a lipidic composition similar to animal microdomains (2). Electrophoresis experiments indicated that these fractions were able to recruit a specific set of plasma membrane proteins and exclude others. We used mass spectrometry to give an extensive description of a tobacco plasma membrane microdomains. This led to the identification of 145 proteins wh…
Hsp60 from cancer cells can reach near and distant targets: A proposal for a multistage pathway
2011
Cancer cells have means to influence other cells in their vicinity and distant, and in this signal-delivering mechanisms the chaperonin Hsp60 plays a role, which is currently being recognized as potentially crucial for the growth and dissemination of at least certain types of tumors. In order to arrive at its destination, Hsp60, a typical resident of mitochondria in normal and tumor cells, leaves the organelle and reaches the blood. In the latter, Hsp60 can travel and arrive at targets situated far away from its origin. The details of the route followed by Hsp60 and their molecular mechanisms have not yet been fully elucidated. We investigated Hsp60 levels and secretion in normal and tumor …