Microdomains such as rafts are considered as scaffolds for phosphatidylinositol (4,5) bisphosphate (PIP2) signaling, enabling PIP2 to selectively regulate different processes in the cell. Enrichment of PIP2 in microdomains was based on cholesterol-depletion and detergent-extraction studies. Here we show that two distinct phospholipase C-coupled receptors (those for neurokinin A and endothelin) share the same, homogeneously distributed PIP2 pool at the plasma membrane, even though the neurokinin A receptor is localized to microdomains and is cholesterol dependent in its PIP2 signaling whereas the endothelin receptor is not. Our experiments further indicate that detergent treatment causes PIP2 clustering and that cholesterol depletion interferes with basal, ligand-independent recycling of the neurokinin A receptor, thereby providing alternative explanations for the enrichment of PIP2 in detergent-insoluble membrane fractions and for the cholesterol dependency of PIP2 breakdown, respectively.
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http://dx.doi.org/10.1038/sj.emboj.7600655 | DOI Listing |
mBio
December 2024
Department of Tropical Medicine and Parasitology, College of Medicine, National Taiwan University, Taipei, Taiwan.
is the etiologic agent of trichomoniasis, one of the most common non-viral sexually transmitted infections globally. Our previous work reported the role of phosphatidylinositol 4,5-bisphosphates (PIP) signaling in the actin-dependent pathogenicity of . This study further demonstrated that iron transiently regulated phosphatidylinositol-4-phosphate 5-kinase (PI4P5K) proteostasis and its complex formation with an active ADP ribosylation factor Arf220, facilitating co-trafficking to the plasma membrane, crucial for PIP production.
View Article and Find Full Text PDFIn vascular smooth muscle cells (VSMCs) and vascular endothelial cells (VECs), phosphatidylinositol 4,5-bisphosphate (PIP) acts as a substrate for phospholipase C (PLC)- and phosphoinositol 3-kinase (PI3K)-mediated signaling pathways and an unmodified ligand at ion channels and other macromolecules, which are key processes in the regulation of cell physiological and pathological phenotypes. It is envisaged that these distinct roles of PIP are achieved by PIP-binding proteins, which act as PIP buffers to produce discrete pools of PIP that permits targeted release within the cell. This review discusses evidence for the expression, cell distribution, and role of myristoylated alanine-rich C-kinase substrate (MARCKS), a PIP-binding protein, in cellular signaling and function of VSMCs.
View Article and Find Full Text PDFBr J Pharmacol
December 2024
Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
Background And Purpose: Paracetamol has been found to alleviate inflammatory pain by modulating K7 channels. Its metabolite N-acetyl-4-benzoquinoneimine (NAPQI) increases currents through these channels via a stretch of three cysteine residues in the channel S2-S3 linker. Through this effect, the excitability of neurons in the pain pathway is dampened.
View Article and Find Full Text PDFTrends Cell Biol
November 2024
Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. Electronic address:
Crosstalk between junctional membrane proteins is vital in the coordinated generation of cellular Ca signals. New evidence (Ivanova et al.) reveals the signaling lipid, phosphatidylinositol 4,5-bisphosphate (PIP) reaches across plasma membrane (PM)-endoplasmic reticulum (ER) junctions to regulate inositol 1,4,5-trisphosphate receptors, controlling the critical progression of local to global Ca signals mediating a spectrum of fundamental cellular responses.
View Article and Find Full Text PDFCell Calcium
December 2024
Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, United States. Electronic address:
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