ATP8A2 is a mammalian P4-ATPase (flippase) that translocates the negatively charged lipid substrate phosphatidylserine from the exoplasmic leaflet to the cytoplasmic leaflet of cellular membranes. Using an electrophysiological method based on solid supported membranes, we investigated the electrogenicity of specific reaction steps of ATP8A2 and explored a potential phospholipid translocation pathway involving residues with positively charged side chains. Changes to the current signals caused by mutations show that the main electrogenic event occurs in connection with the release of the bound phosphatidylserine to the cytoplasmic leaflet and support the hypothesis that the phospholipid interacts with specific lysine and arginine residues near the cytoplasmic border of the lipid bilayer during the translocation and reorientation required for insertion into the cytoplasmic leaflet.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/1873-3468.14459 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Substrates, regulation, cellular functions, and disease associations of P4-ATPases.
Commun Biol
January 2025
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
P4-ATPases, a subfamily of the P-type ATPase superfamily, play a crucial role in translocating membrane lipids from the exoplasmic/luminal leaflet to the cytoplasmic leaflet. This process generates and regulates transbilayer lipid asymmetry. These enzymes are conserved across all eukaryotes, and the human genome encodes 14 distinct P4-ATPases.
View Article and Find Full Text PDFFRAP Assay to Trace Lipid Mixing of the Inner and Outer Leaflet of Yeast Vacuoles: Assessing the Fusion State in Live Cells.
Methods Mol Biol
January 2025
Department of Immunobiology, University of Lausanne, Epalinges, Switzerland.
Fluorescence recovery after photobleaching (FRAP) can be employed to investigate membrane lipid mixing of vacuoles in live budding yeast cells and distinguish the fused, hemi-fused or non-fused states of these organelles under physiological conditions. Here, we describe a protocol for labeling the outer and inner leaflets of vacuoles in live cells that allow to detect hemifusion intermediates and, thus, identify components necessary for fusion pore opening.
View Article and Find Full Text PDFUnlabelled: Cytoplasmic proteins must recruit to membranes to function in processes such as endocytosis and cell division. Many of these proteins recognize not only the chemical structure of the membrane lipids, but the curvature of the surface, binding more strongly to more highly curved surfaces, or 'curvature sensing'. Curvature sensing by amphipathic helices is known to vary with membrane bending rigidity, but changes to lipid composition can simultaneously alter membrane thickness, spontaneous curvature, and leaflet symmetry, thus far preventing a systematic characterization of lipid composition on such curvature sensing through either experiment or simulation.
View Article and Find Full Text PDFIts own architect: Flipping cardiolipin synthase.
Sci Adv
January 2025
Department of Biochemistry and Molecular Biology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Article Synopsis
- Current understanding posits that lipid asymmetry in cell membranes is actively kept and not essential for survival, yet the inner membrane (IM) shows notable asymmetry.
- Researchers created a specific mutant lacking phosphatidylethanolamine (PE) that relies on cardiolipin (CL) for its IM viability, uncovering how the distribution of CL is regulated in the membrane.
- The study reveals that the enzyme ClsA adapts its structure in response to varying levels of PE, highlighting a potentially novel mechanism for sustaining lipid asymmetry in membranes without the need for specialized flippase proteins.
Cell membranes sustain phospholipid imbalance via cholesterol asymmetry.
bioRxiv
December 2024
Department of Molecular Physiology and Biological Physics, University of Virginia; Charlottesville, VA 22903, USA.
Membranes are molecular interfaces that compartmentalize cells to control the flow of nutrients and information. These functions are facilitated by diverse collections of lipids, nearly all of which are distributed asymmetrically between the two bilayer leaflets. Most models of biomembrane structure and function often include the implicit assumption that these leaflets have similar abundances of phospholipids.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!