Anant K. Menon

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We present a quantitative description of the molecular species composition of the major phospholipid classes in bloodstream and procyclic forms of Trypanosoma brucei. Phospholipid classes were resolved by 2-dimensional thin-layer chromatography. Diradylglycerols were released from individual phospholipid classes by phospholipases C, converted into benzoate(More)
Glycosylphosphatidylinositol (GPI) anchoring of cell surface proteins is the most complex and metabolically expensive of the lipid posttranslational modifications described to date. The GPI anchor is synthesized via a membrane-bound multistep pathway in the endoplasmic reticulum (ER) requiring >20 gene products. The pathway is initiated on the cytoplasmic(More)
Sterol transport between the endoplasmic reticulum (ER) and plasma membrane (PM) occurs by an ATP-dependent, non-vesicular mechanism that is presumed to require sterol transport proteins (STPs). In Saccharomyces cerevisiae, homologs of the mammalian oxysterol-binding protein (Osh1-7) have been proposed to function as STPs. To evaluate this proposal we took(More)
The lipid composition of cellular organelles is tailored to suit their specialized tasks. A fundamental transition in the lipid landscape divides the secretory pathway in early and late membrane territories, allowing an adaptation from biogenic to barrier functions. Defending the contrasting features of these territories against erosion by vesicular traffic(More)
The mechanism by which newly synthesized sterols are transported from their site of synthesis, the endoplasmic reticulum (ER), to the sterol-enriched plasma membrane (PM) is not fully understood. Studies in mammalian cells suggest that newly synthesized cholesterol is transported to the PM in Golgi-bypassing vesicles and/or via a nonvesicular process. Using(More)
Phospholipid (PL) scramblases disrupt the lipid asymmetry of the plasma membrane, externalizing phosphatidylserine to trigger blood coagulation and mark apoptotic cells. Recently, members of the TMEM16 family of Ca(2+)-gated channels have been shown to be involved in Ca(2+)-dependent scrambling. It is however controversial whether they are scramblases or(More)
Controlled cross-linking of IgE-receptor complexes on the surface of rat basophilic leukemia cells and mast cells has allowed a comparison of the lateral mobility and cell triggering activity of monomers, dimers, and higher oligomers of receptors. Addition of a monoclonal anti-IgE(Fc) antibody to IgE-sensitized cells in stoichiometric amounts relative to(More)
We investigated the transbilayer movement or flip-flop of phospholipids in vesicles derived from the cytoplasmic membrane of Bacillus megaterium. Since common assay techniques were found to be inapplicable to the Bacillus system, we exploited and elaborated a newly described method in which fluorescent phospholipids (1-myristoyl-2-C6-NBD phospholipids) are(More)
Transbilayer flipping of glycerophospholipids in the endoplasmic reticulum (ER) is a key feature of membrane biogenesis. Flipping appears to be an ATP-independent, bidirectional process facilitated by specific proteins or flippases. Although a phospholipid flippase has yet to be identified, evidence supporting the existence of dedicated flippases was(More)
We recently showed that transport of ergosterol from the ER (endoplasmic reticulum) to the sterol-enriched PM (plasma membrane) in yeast occurs by a non-vesicular (Sec18p-independent) mechanism that results in the equilibration of sterol pools in the two organelles [Baumann, Sullivan, Ohvo-Rekilä, Simonot, Pottekat, Klaassen, Beh and Menon (2005)(More)