Search results for "Membrane Lipids"
showing 10 items of 80 documents
The Role of Phospholipase D and MAPK Signaling Cascades in the Adaption of Lichen Microalgae to Desiccation: Changes in Membrane Lipids and Phosphopr…
2016
Classically, lichen phycobionts are described as poikilohydric organisms able to undergo desiccation due to the constitutive presence of molecular protection mechanisms. However, little is known about the induction of cellular responses in lichen phycobionts during drying. The analysis of the lipid composition of the desiccated lichen microalga Asterochloris erici revealed the unusual accumulation of highly polar lipids (oligogalactolipids and phosphatidylinositol), which prevents the fusion of membranes during stress, but also the active degradation of cone-shaped lipids (monogalactosyldiacylglycerol and phosphatidylethanolamine) to stabilize membranes in desiccated cells. The level of pho…
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…
Membrane glycerolipid remodeling triggered by nitrogen and phosphorus starvation in Phaeodactylum tricornutum.
2014
International audience; Diatoms constitute a major phylum of phytoplankton biodiversity in ocean water and freshwater ecosystems. They are known to respond to some chemical variations of the environment by the accumulation of triacylglycerol, but the relative changes occurring in membrane glycerolipids have not yet been studied. Our goal was first to define a reference for the glycerolipidome of the marine model diatom Phaeodactylum tricornutum, a necessary prerequisite to characterize and dissect the lipid metabolic routes that are orchestrated and regulated to build up each subcellular membrane compartment. By combining multiple analytical techniques, we determined the glycerolipid profil…
Organization into Higher Ordered Ring Structures Counteracts Membrane Binding of IM30, a Protein Associated with Inner Membranes in Chloroplasts and …
2016
The IM30 (inner membrane-associated protein of 30 kDa), also known as the Vipp1 (vesicle-inducing protein in plastids 1), has a crucial role in thylakoid membrane biogenesis and maintenance. Recent results suggest that the protein binds peripherally to membranes containing negatively charged lipids. However, although IM30 monomers interact and assemble into large oligomeric ring complexes with different numbers of monomers, it is still an open question whether ring formation is crucial for membrane interaction. Here we show that binding of IM30 rings to negatively charged phosphatidylglycerol membrane surfaces results in a higher ordered membrane state, both in the head group and in the inn…
Proton Leakage Is Sensed by IM30 and Activates IM30-Triggered Membrane Fusion
2020
The inner membrane-associated protein of 30 kDa (IM30) is crucial for the development and maintenance of the thylakoid membrane system in chloroplasts and cyanobacteria. While its exact physiological function still is under debate, it has recently been suggested that IM30 has (at least) a dual function, and the protein is involved in stabilization of the thylakoid membrane as well as in Mg2+-dependent membrane fusion. IM30 binds to negatively charged membrane lipids, preferentially at stressed membrane regions where protons potentially leak out from the thylakoid lumen into the chloroplast stroma or the cyanobacterial cytoplasm, respectively. Here we show in vitro that IM30 membrane binding…
Ratiometric fluorescence live imaging analysis of membrane lipid order in Arabidopsis mitotic cells using a lipid order-sensitive probe
2016
SPE Pôle IPM; International audience; Eukaryotic cells contain membranes exhibiting different levels of lipid order mostly related to their relative amount of sterol-rich domains, thought to mediate temporal and spatial organization of cellular processes. We previously provided evidence in Arabidopsis thaliana that sterols are crucial for execution of cytokinesis, the last stage of cell division. Recently, we used di-4-ANEPPDHQ, a fluorescent probe sensitive to order of lipid phases, to quantify the level of membrane order of the cell plate, the membrane structure separating daughter cells during somatic cytokinesis of higher plant cells. By employing quantitative, ratiometric fluorescence …
Direct observation of alpha-lactalbumin, adsorption and incorporation into lipid membrane and formation of lipid/protein hybrid structures
2019
The interaction between proteins and membranes is of great interest in biomedical and biotechnological research for its implication in many functional and dysfunctional processes. We present an experimental study on the interaction between model membranes and alpha-lactalbumin (alpha-La). alpha-La is widely studied for both its biological function and its anti-tumoral properties. We use advanced fluorescence microscopy and spectroscopy techniques to characterize alpha-La-membrane mechanisms of interaction and alpha-La-induced modifications of membranes when insertion of partially disordered regions of protein chains in the lipid bilayer is favored. Moreover, using fluorescence lifetime imag…
Border controls: Lipids control proteins and proteins control lipids.
2016
Anhydrobiosis in yeast: Glutathione overproduction improves resistance to dehydration of a recombinant Ogataea (Hansenula) polymorpha strain
2018
Abstract We show for the first time that a recombinant strain of yeast Ogataea (Hansenula) polymorpha is at least as tolerant to dehydration-rehydration treatment as the wild type strain. It is believed that this unusual characteristic of this recombinant yeast strain is linked with its ability to overproduce glutathione. Based on plasma membrane permeability analysis, we hypothesise that glutathione, in addition to its powerful antioxidative protective effects on membrane lipids, may also protect membrane proteins and/or nucleic acids. The combination of yeast cell dehydration with immobilisation and subsequent preliminary slow rehydration in water vapour gave good results in terms of reco…
Response of membrane-bound ATPase of Micrococcus luteus to heat and ultraviolet light.
1976
It is shown that the properties of ATPase (EC 3.6.1.3) of Micrococcus luteus depend only to some extent on the state of the membrane to which it is attached. Its interaction with the membrane appears to be largely controlled by polar forces. It is shown, however, that the UV-sensitivity of the membrane-bound ATPase is also significantly influenced by the state of membrane lipids.