Folding, assembly, and trafficking of ion channels are tightly controlled processes and are important for biological functions relevant to health and disease. Here, we report that functional expression of the Eag channel is temperature-sensitive by a mechanism that is independent of trafficking or surface targeting of the channel protein. Eag channels in cells grown at 37 °C exhibit voltage-evoked gating charge movements but fail to conduct K(+) ions. By mutagenesis and chimeric channel studies, we show that the N- and C-terminal regions are involved in controlling a step after movement of the voltage sensor, as well as in regulating biophysical properties of the Eag channel. Synthesis and assembly of Eag at high temperature disrupt the ability of these domains to carry out their function. These results suggest an important role of the intracellular regions in the generation of Eag currents.
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http://dx.doi.org/10.1074/jbc.M110.184077 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA 95616.
Seeds are complex structures composed of three regions, embryo, endosperm, and seed coat, with each further divided into subregions that consist of tissues, cell layers, and cell types. Although the seed is well characterized anatomically, much less is known about the genetic circuitry that dictates its spatial complexity. To address this issue, we profiled mRNAs from anatomically distinct seed subregions at several developmental stages.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390.
Neurotransmitter release is triggered in microseconds by Ca-binding to the Synaptotagmin-1 C-domains and by SNARE complexes that form four-helix bundles between synaptic vesicles and plasma membranes, but the coupling mechanism between Ca-sensing and membrane fusion is unknown. Release requires extension of SNARE helices into juxtamembrane linkers that precede transmembrane regions (linker zippering) and binding of the Synaptotagmin-1 CB domain to SNARE complexes through a "primary interface" comprising two regions (I and II). The Synaptotagmin-1 Ca-binding loops were believed to accelerate membrane fusion by inducing membrane curvature, perturbing lipid bilayers, or helping bridge the membranes, but SNARE complex binding through the primary interface orients the Ca-binding loops away from the fusion site, hindering these putative activities.
View Article and Find Full Text PDFACS Chem Neurosci
January 2025
Department of Bioengineering and Biotechnology, Birla Institute of Technology Mesra, Ranchi, Jharkhand 835215, India.
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, extracellular amyloid-β (Aβ) plaque accumulation, and intracellular neurofibrillary tangles. Recent efforts to find effective therapies have increased interest in natural compounds with multifaceted effects on AD pathology. This study explores natural compounds for their potential to mitigate AD pathology using molecular docking, ADME screening, and assays, with ruscogenin─a steroidal sapogenin from emerging as a promising candidate.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Biological Sciences and Biotechnology, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea.
Antimicrobial peptides (AMPs) are promising agents for treating antibiotic-resistant bacterial infections. Although discovering novel AMPs is crucial for combating multidrug-resistant bacteria and biofilm-related infections, their clinical potential relies on precise, real-time evaluation of efficacy, toxicity, and mechanisms. Optical diffraction tomography (ODT), a label-free imaging technology, enables real-time visualization of bacterial morphological changes, membrane damage, and biofilm formation over time.
View Article and Find Full Text PDFBiochemistry
January 2025
Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar 160062, Punjab, India.
Aptamers bind to their targets with exceptional affinity and specificity. However, their intracellular application is hampered by the lack of knowledge about the effect of the cellular milieu on the RNA structure/stability. In this study, cellular crowding was mimicked using polyethylene glycol (PEG), and the crucial role of Mg ions in stabilizing the structure of an RNA aptamer was investigated.
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