Publications by authors named "Adiilah Mamode Cassim"

5 Publications

  • Page 1 of 1

Biophysical analysis of the plant-specific GIPC sphingolipids reveals multiple modes of membrane regulation.

J Biol Chem 2021 Jan-Jun;296:100602. Epub 2021 Mar 27.

Laboratoire de Biogènese Membranaire, UMR 5200, CNRS, Université de Bordeaux, Villenave d'Ornon Cedex, France. Electronic address:

The plant plasma membrane (PM) is an essential barrier between the cell and the external environment, controlling signal perception and transmission. It consists of an asymmetrical lipid bilayer made up of three different lipid classes: sphingolipids, sterols, and phospholipids. The glycosyl inositol phosphoryl ceramides (GIPCs), representing up to 40% of total sphingolipids, are assumed to be almost exclusively in the outer leaflet of the PM. However, their biological role and properties are poorly defined. In this study, we investigated the role of GIPCs in membrane organization. Because GIPCs are not commercially available, we developed a protocol to extract and isolate GIPC-enriched fractions from eudicots (cauliflower and tobacco) and monocots (leek and rice). Lipidomic analysis confirmed the presence of trihydroxylated long chain bases and 2-hydroxylated very long-chain fatty acids up to 26 carbon atoms. The glycan head groups of the GIPCs from monocots and dicots were analyzed by gas chromatograph-mass spectrometry, revealing different sugar moieties. Multiple biophysics tools, namely Langmuir monolayer, ζ-Potential, light scattering, neutron reflectivity, solid state 2H-NMR, and molecular modeling, were used to investigate the physical properties of the GIPCs, as well as their interaction with free and conjugated phytosterols. We showed that GIPCs increase the thickness and electronegativity of model membranes, interact differentially with the different phytosterols species, and regulate the gel-to-fluid phase transition during temperature variations. These results unveil the multiple roles played by GIPCs in the plant PM.
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http://dx.doi.org/10.1016/j.jbc.2021.100602DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8099651PMC
March 2021

Sphingolipids in plants: a guidebook on their function in membrane architecture, cellular processes, and environmental or developmental responses.

FEBS Lett 2020 11 24;594(22):3719-3738. Epub 2020 Nov 24.

Laboratoire de Biogenèse Membranaire, UMR5200, Université de Bordeaux, CNRS, Villenave d'Ornon, France.

Sphingolipids are fundamental lipids involved in various cellular, developmental and stress-response processes. As such, they orchestrate not only vital molecular mechanisms of living cells but also act in diseases, thus qualifying as potential pharmaceutical targets. Sphingolipids are universal to eukaryotes and are also present in some prokaryotes. Some sphingolipid structures are conserved between animals, plants and fungi, whereas others are found only in plants and fungi. In plants, the structural diversity of sphingolipids, as well as their downstream effectors and molecular and cellular mechanisms of action, are of tremendous interest to both basic and applied researchers, as about half of all small molecules in clinical use originate from plants. Here, we review recent advances towards a better understanding of the biosynthesis of sphingolipids, the diversity in their structures as well as their functional roles in membrane architecture, cellular processes such as membrane trafficking and cell polarity, and cell responses to environmental or developmental signals.
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http://dx.doi.org/10.1002/1873-3468.13987DOI Listing
November 2020

Lipids light up in plant membranes.

Nat Plants 2019 09;5(9):913-914

Laboratoire de Biogènese Membranaire, UMR 5200, CNRS, University of Bordeaux, Bordeaux, France.

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http://dx.doi.org/10.1038/s41477-019-0494-9DOI Listing
September 2019

Plant lipids: Key players of plasma membrane organization and function.

Prog Lipid Res 2019 01 19;73:1-27. Epub 2018 Nov 19.

Laboratoire de Biogenèse Membranaire (LBM), CNRS, University of Bordeaux, UMR 5200, F-33882 Villenave d'Ornon, France. Electronic address:

The plasma membrane (PM) is the biological membrane that separates the interior of all cells from the outside. The PM is constituted of a huge diversity of proteins and lipids. In this review, we will update the diversity of molecular species of lipids found in plant PM. We will further discuss how lipids govern global properties of the plant PM, explaining that plant lipids are unevenly distributed and are able to organize PM in domains. From that observation, it emerges a complex picture showing a spatial and multiscale segregation of PM components. Finally, we will discuss how lipids are key players in the function of PM in plants, with a particular focus on plant-microbe interaction, transport and hormone signaling, abiotic stress responses, plasmodesmata function. The last chapter is dedicated to the methods that the plant membrane biology community needs to develop to get a comprehensive understanding of membrane organization in plants.
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http://dx.doi.org/10.1016/j.plipres.2018.11.002DOI Listing
January 2019

Eudicot plant-specific sphingolipids determine host selectivity of microbial NLP cytolysins.

Science 2017 12;358(6369):1431-1434

Centre of Plant Molecular Biology, Eberhard-Karls-University Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.

Necrosis and ethylene-inducing peptide 1-like (NLP) proteins constitute a superfamily of proteins produced by plant pathogenic bacteria, fungi, and oomycetes. Many NLPs are cytotoxins that facilitate microbial infection of eudicot, but not of monocot plants. Here, we report glycosylinositol phosphorylceramide (GIPC) sphingolipids as NLP toxin receptors. Plant mutants with altered GIPC composition were more resistant to NLP toxins. Binding studies and x-ray crystallography showed that NLPs form complexes with terminal monomeric hexose moieties of GIPCs that result in conformational changes within the toxin. Insensitivity to NLP cytolysins of monocot plants may be explained by the length of the GIPC head group and the architecture of the NLP sugar-binding site. We unveil early steps in NLP cytolysin action that determine plant clade-specific toxin selectivity.
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http://dx.doi.org/10.1126/science.aan6874DOI Listing
December 2017