Phosphatidylinositol 4,5-biphosphate (PtdIns(4,5)P2), an important element in eukaryotic signal transduction, is synthesized either by phosphatidylinositol-4-phosphate 5-kinase (PtdIns(4)P 5K) from phosphatidylinositol 4-phosphate (PtdIns(4)P) or by phosphatidylinositol-5-phosphate 4-kinase (PtdIns(5)P 4K) from phosphatidylinositol 5-phosphate (PtdIns(5)P). Two Saccharomyces cerevisiae genes, MSS4 and FAB1, are homologous to mammalian PtdIns(4)P 5Ks and PtdIns(5)P 4Ks. We show here that MSS4 is a functional homolog of mammalian PtdIns(4)P 5K but not of PtdIns(5)P 4K in vivo. We constructed a hemagglutinin epitope-tagged form of Mss4p and found that Mss4p has PtdIns(4)P 5K activity. Immunofluorescent and fractionation studies of the epitope-tagged Mss4p suggest that Mss4p is localized on the plasma membrane, whereas Fab1p is reportedly localized on the vacuolar membrane. A temperature-sensitive mss4-1 mutant was isolated, and its phenotypes at restrictive temperatures were found to include increased cell size, round shape, random distribution of actin patches, and delocalized staining of cell wall chitin. Thus, biochemical and genetic analyses on Mss4p indicated that yeast PtdIns(4)P 5K localized on the plasma membrane is required for actin organization.
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http://dx.doi.org/10.1074/jbc.273.25.15779 | DOI Listing |
Fluids Barriers CNS
January 2025
Neurology 5 - Neuropathology Unit, Fondazione IRCCS - Istituto Neurologico Carlo Besta, Via Celoria 11, Milan, 20133, Italy.
Background: The approval of new disease-modifying therapies by the U.S. Food and Drug Administration and the European Medicine Agency makes it necessary to optimize non-invasive and cost-effective tools for the identification of subjects at-risk of developing Alzheimer's Disease (AD).
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January 2025
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China.
Electron transfer is ubiquitous in many chemical reactions and biological phenomena; however, the spatial heterogeneities of electron transfer kinetics in electrocatalysis are so far insufficiently resolved. Measuring and understanding the localized electron transfer are crucial to deciphering the intrinsic activity of electrocatalysts and to achieving further improvements in performance. By using scanning electrochemical probe microscopy to spatially resolve redox electrochemistry across the single-crystalline surface of gold microplates, we discover an intriguing radially distributed electron transfer pattern, where the kinetics around the periphery region are significantly higher than those at the central region, regardless of the redox reaction types.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
January 2025
Comenius University Bratislava, Faculty of Pharmacy, Department of Pharmacology and Toxicology, Bratislava, Slovakia.
Cholinesterase (ChE) inhibitors are under consideration to be used in the treatment of cardiovascular pathologies. A prerequisite to advancing ChE inhibitors into the clinic is their thorough characterization in the heart. The aim here was to provide a detailed analysis of cardiac ChE to understand their molecular composition, localization, and physiological functions.
View Article and Find Full Text PDFPlant Mol Biol
January 2025
School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan, 411201, China.
Deficiency or excess of mineral elements in the environment is a primary factor limiting crop yields and nutritional quality. Lotus (Nelumbo nucifera) is an important aquatic crop in Asia, but the mechanism for accumulating mineral nutrients and coping with nutrient deficiency/excess is still largely unknown. Here, we identified NnMTP10, a member of the cation diffusion facilitator family, by screening the cDNA library of lotus.
View Article and Find Full Text PDFEnviron Monit Assess
January 2025
Department of Earth Science, University of Bizerte-FSB, University of Carthage, 7120, Bizerte, Tunisia.
The Ichkeul-Bizerte Lagoon Complex (IBLC), a critical ecosystem for local biodiversity, faces a pressing threat due to climate change and severe pollution. Despite past conservation efforts, pollution persists, particularly in the Bizerte Lagoon. This study investigated the impact of water dynamics and climatic conditions on heavy metal contamination in the IBLC's sediments.
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