Several proteins at endoplasmic reticulum (ER)-Golgi membrane contact sites contain a PH domain that interacts with the Golgi phosphoinositide PI(4)P, a FFAT motif that interacts with the ER protein VAP-A, and a lipid transfer domain. This architecture suggests the ability to both tether organelles and transport lipids between them. We show that in oxysterol binding protein (OSBP) these two activities are coupled by a four-step cycle. Membrane tethering by the PH domain and the FFAT motif enables sterol transfer by the lipid transfer domain (ORD), followed by back transfer of PI(4)P by the ORD. Finally, PI(4)P is hydrolyzed in cis by the ER protein Sac1. The energy provided by PI(4)P hydrolysis drives sterol transfer and allows negative feedback when PI(4)P becomes limiting. Other lipid transfer proteins are tethered by the same mechanism. Thus, OSBP-mediated back transfer of PI(4)P might coordinate the transfer of other lipid species at the ER-Golgi interface.
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http://dx.doi.org/10.1016/j.cell.2013.09.056 | DOI Listing |
J Phys Chem B
January 2025
Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg 79104, Germany.
The selective insertion of membrane-impermeant amphiphiles such as detergents, (lipo)peptides, drugs, etc. into the leaflet of a membrane causes an imbalance between the intrinsic areas of the and leaflet, referred to as asymmetry stress or differential stress. The literature provides individual mechanisms of how membranes respond to such stress, which are relevant to membrane remodeling processes and leakage phenomena.
View Article and Find Full Text PDFJ Membr Biol
January 2025
School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha, 768 109, India.
Membrane fusion is the first step in the infection process of the enveloped viruses. Enveloped viruses fuse either at the cell surface or enter the cell through endocytosis and transfer their internal genetic materials by fusing with the endosomal membrane at acidic pH. In this work, we have evaluated the effect of the Dengue virus fusion peptide (DENV FP) on the polyethylene glycol (PEG)-mediated lipid mixing of vesicles (hemifusion formation) at pH 5 and pH 7.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
January 2025
Research Institute of the, McGill University Health Centre, Montreal, QC, Canada.
The increasing shift from cannabis smoking to cannabis vaping is largely driven by the perception that vaping to form an aerosol represents a safer alternative to smoking and is a form of consumption appealing to youth. Herein, we compared the chemical composition and receptor-mediated activity of cannabis smoke extract (CaSE) to cannabis vaping extract (CaVE) along with the biological response in human bronchial epithelial cells. Chemical analysis using HPLC and GC/MS revealed that cannabis vaping aerosol contained fewer toxicants than smoke; CaSE and CaVE contained teratogens, carcinogens, and respiratory toxicants.
View Article and Find Full Text PDFClin Rev Allergy Immunol
January 2025
Department of Laboratory Medicine, Guangdong Provincial Key Laboratory of Precision Medical Diagnostics, Guangdong Engineering and Technology Research Center for Rapid Diagnostic Biosensors, Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, People's Republic of China.
Exosomes, small extracellular vesicles secreted by various cell types, have emerged as key players in the pathophysiology of autoimmune diseases. These vesicles serve as mediators of intercellular communication, facilitating the transfer of bioactive molecules such as proteins, lipids, and nucleotide. In autoimmune diseases, exosomes have been implicated in modulating immune responses, oxidative stress, autophagy, gut microbes, and the cell cycle, contributing to disease initiation, progression, and immune dysregulation.
View Article and Find Full Text PDFNat Metab
January 2025
Centre for Orthopaedic Research, Medical School of the University of Western Australia, Nedlands, Western Australia, Australia.
Intercellular mitochondria transfer is an evolutionarily conserved process in which one cell delivers some of their mitochondria to another cell in the absence of cell division. This process has diverse functions depending on the cell types involved and physiological or disease context. Although mitochondria transfer was first shown to provide metabolic support to acceptor cells, recent studies have revealed diverse functions of mitochondria transfer, including, but not limited to, the maintenance of mitochondria quality of the donor cell and the regulation of tissue homeostasis and remodelling.
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