Secondary active membrane transporters harness the energy of ion gradients to concentrate their substrates. Homologous transporters evolved to couple transport to different ions in response to changing environments and needs. The bases of such diversification, and thus principles of ion coupling, are unexplored. Employing phylogenetics and ancestral protein reconstruction, we investigated sodium-coupled transport in prokaryotic glutamate transporters, a mechanism ubiquitous across life domains and critical to neurotransmitter recycling in humans. We found that the evolutionary transition from sodium-dependent to independent substrate binding to the transporter preceded changes in the coupling mechanism. Structural and functional experiments suggest that the transition entailed allosteric mutations, making sodium binding dispensable without affecting ion-binding sites. Allosteric tuning of transporters' energy landscapes might be a widespread route of their functional diversification.
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http://dx.doi.org/10.1101/2023.12.03.569786 | DOI Listing |
Toxicon
January 2025
National Council of Research (CNR), Institute of Biochemistry and Cell Biology, 00015 Monterotondo (RM), Italy.
Botulinum neurotoxin type A (BoNT/A) has expanded its therapeutic uses beyond neuromuscular disorders to include treatments for various pain syndromes and neurological conditions. Originally recognized for blocking acetylcholine release at neuromuscular junctions, BoNT/A's effects extend to both peripheral and central nervous systems. Its ability to undergo retrograde transport allows BoNT/A to modulate synaptic transmission and reduce pain centrally, influencing neurotransmitter systems beyond muscle control.
View Article and Find Full Text PDFJ Adv Res
January 2025
Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China. Electronic address:
Introduction: Autism spectrum disorder (ASD) represents a multifaceted set of neurodevelopmental conditions marked by social deficits and repetitive behaviors. Astragaloside IV (ASIV), a natural compound derived from the traditional Chinese herb Astragali Radix, exhibits robust neuroprotective effects. However, whether ASIV can ameliorate behavioral deficits in ASD remains unknown.
View Article and Find Full Text PDFPharmaceuticals (Basel)
January 2025
Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, PR 00716, USA.
Background/objectives: Cocaine use disorder is an intersecting issue in populations with HIV-1, further exacerbating the clinical course of the disease and contributing to neurotoxicity and neuroinflammation. Cocaine and HIV neurotoxins play roles in neuronal damage during neuroHIV progression by disrupting glutamate homeostasis in the brain. Even with combined antiretroviral therapy (cART), HIV-1 Nef, an early viral protein expressed in approximately 1% of infected astrocytes, remains a key neurotoxin.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Almazov National Medical Research Centre, 197341 St. Petersburg, Russia.
Several mutations of the uppermost arginine, R219, in the voltage-sensing sliding helix S4 of cardiac sodium channel Nav1.5 are reported in the ClinVar databases, but the clinical significance of the respective variants is unknown (VUSs). AlphaFold 3 models predicted a significant downshift of S4 in the R219C VUS.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Program in Neuroscience, Department of Biology, Syracuse University, Syracuse, NY 13210, USA.
Astrocytes produce and export glutathione (GSH), an important thiol antioxidant essential for protecting neural cells from oxidative stress and maintaining optimal brain health. While it has been established that oxidative stress increases GSH production in astrocytes, with Nrf2 acting as a critical transcription factor regulating key components of the GSH synthetic pathway, the role of Nrf2 in controlling constitutive GSH synthetic and release mechanisms remains incompletely investigated. Our data show that naïve primary mouse astrocytes cultured from the cerebral cortices of Nrf2 knockout (Nrf2) pups have significantly less intracellular and extracellular GSH levels when compared to astrocytes cultured from Nrf2 wild-type (Nrf2) pups.
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