Transient receptor potential melastatin subfamily member 4 (TRPM4) is a widely distributed, calcium-activated, monovalent-selective cation channel. Mutations in human TRPM4 (hTRPM4) result in progressive familial heart block. Here, we report the electron cryomicroscopy structure of hTRPM4 in a closed, Na-bound, apo state at pH 7.5 to an overall resolution of 3.7 Å. Five partially hydrated sodium ions are proposed to occupy the center of the conduction pore and the entrance to the coiled-coil domain. We identify an upper gate in the selectivity filter and a lower gate at the entrance to the cytoplasmic coiled-coil domain. Intramolecular interactions exist between the TRP domain and the S4-S5 linker, N-terminal domain, and N and C termini. Finally, we identify aromatic interactions via π-π bonds and cation-π bonds, glycosylation at an N-linked extracellular site, a pore-loop disulfide bond, and 24 lipid binding sites. We compare and contrast this structure with other TRP channels and discuss potential mechanisms of regulation and gating of human full-length TRPM4.
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http://dx.doi.org/10.1073/pnas.1722038115 | DOI Listing |
Stem Cell Res
December 2024
Fraunhofer Institute for Translational Medicine and Pharmacology ITPM, Discovery Research ScreeningPort, Hamburg, Germany. Electronic address:
Two isogenic hiPSC lines, ZIPi013-B-1 and ZIPi013-B-2, were generated by CRISPR/Cas9-mediated indels in the TRPM4 gene of the previously published ZIPi013-B. TRPM4 belongs to the evolutionarily conserved family of transient receptor potential (TRP) channels. It is expressed ubiquitously and its activity is regulated by intracellular calcium binding, changes in membrane potential, phosphoinositide lipids in the plasma membrane and the local concentration of cytoplasmic ATP and ADP.
View Article and Find Full Text PDFBiochem J
November 2024
Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
Erythrokeratodermia variabilis et progressiva (EKVP) is a rare hereditary skin disorder characterized by hyperkeratotic plaques and erythematous patches that progressively worsen with age. This disorder has been associated with variants in three connexin encoding genes (GJA1, GJB3, GJB4) and four unrelated genes (KRT83, KDSR, TRPM4, PERP). Most cases of connexin-linked EKVP exhibit an autosomal dominant mode of inheritance, with rare autosomal recessive cases.
View Article and Find Full Text PDFElife
November 2024
Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States.
Transient receptor potential (TRP) channels are a large and diverse family of tetrameric cation-selective channels that are activated by many different types of stimuli, including noxious heat or cold, organic ligands such as vanilloids or cooling agents, or intracellular Ca. Structures available for all subtypes of TRP channels reveal that the transmembrane domains are closely related despite their unique sensitivity to activating stimuli. Here, we use computational and electrophysiological approaches to explore the conservation of the cooling agent binding pocket identified within the S1-S4 domain of the Melastatin subfamily member TRPM8, the mammalian sensor of noxious cold, with other TRPM channel subtypes.
View Article and Find Full Text PDFInt J Mol Sci
October 2024
Consortium for Health and Military Performance, Department of Military and Emergency Medicine, F. Edward Hébert School of Medicine, Uniformed Services University, Bethesda, MD 20814, USA.
J Physiol Sci
September 2024
Laboratory of Functional Physiology, Department of Environmental and Life Sciences, School of Food and Nutritional Sciences, University of Shizuoka, Yada 52-1, Suruga-Ku, Shizuoka, Shizuoka, 422-8526, Japan.
Temperature detection is essential for the survival and perpetuation of any species. Thermoreceptors in the skin sense body temperature as well as the temperatures of ambient air and objects. Since Dr.
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