Equilibrative nucleoside transporters (ENTs) are integral membrane proteins that facilitate the movement of nucleosides and hydrophilic nucleoside analog (NA) drugs across cell membranes. ENTs are also targets for cardioprotectant drugs, which block re-uptake of the purine nucleoside adenosine, thereby enhancing purinergic receptor signaling pathways. ENTs are therefore important contributors to drug bioavailability and efficacy. Despite this important clinical role, very little is known about the structure and regulation of ENTs. Biochemical and structural studies on ENT proteins have been limited by their low endogenous expression levels, hydrophobicity and labile nature. To address these issues, we developed an approach whereby tagged mammalian ENT1 protein was over-expressed in mammalian cell lines, confirmed to be functional and isolated by affinity purification to sufficient levels to be analyzed using MALDI-TOF and tandem MS mass spectrometry. This proteomic approach will allow for a more detailed analysis of the structure, function and regulation of ENTs in the future.
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http://dx.doi.org/10.1016/j.pep.2010.04.008 | DOI Listing |
Cancer Res
December 2024
Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.
Immunosuppression by adenosine is an important cancer immune checkpoint. Extracellular adenosine signals through specific receptors and can be transported across the cell membrane through nucleoside transporters. While adenosine receptors are well-known to regulate tumor immunity, the impact of adenosine transporters remains unexplored.
View Article and Find Full Text PDFCell Host Microbe
December 2024
Institute for Plant Sciences, University of Cologne, Cologne, Germany; Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany. Electronic address:
The intracellular colonization of plant roots by the beneficial fungal endophyte Serendipita indica follows a biphasic strategy, including a host cell death phase that enables successful colonization of Arabidopsis thaliana roots. How host cell death is initiated and controlled is largely unknown. Here, we show that two fungal enzymes, the ecto-5'-nucleotidase SiE5NT and the nuclease SiNucA, act synergistically in the apoplast at the onset of cell death to produce deoxyadenosine (dAdo).
View Article and Find Full Text PDFNat Commun
November 2024
Hannover Medical School, Institute of Virology, Hanover, Germany.
Structure predictions have become invaluable tools, but viral proteins are absent from the EMBL/DeepMind AlphaFold database. Here, we provide proteome-wide structure predictions for all nine human herpesviruses and analyze them in depth with explicit scoring thresholds. By clustering these predictions into structural similarity groups, we identified new families, such as the HCMV UL112-113 cluster, which is conserved in alpha- and betaherpesviruses.
View Article and Find Full Text PDFBiochem Pharmacol
January 2025
Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar Universidade do Porto (ICBAS-UP), 4050-313 Porto, Portugal; Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP/RISE-Health), Instituto de Ciências Biomédicas de Abel Salazar Universidade do Porto (ICBAS-UP), 4050-313 Porto, Portugal. Electronic address:
Nicotinic α7 receptors (α7 nAChRs) present in perisynaptic Schwann cells (PSCs) control acetylcholine (ACh) spillover from the neuromuscular synapse by transiently increasing intracellular Ca, which fosters adenosine release via type 1 equilibrative nucleoside transporters (ENT1) and retrograde activation of presynaptic A inhibitory receptors. The putative Ca-dependent pathways downstream α7 nAChRs involved in the sensing inhibitory drive operated by PSCs is unknown. Herein, we used phrenic nerve-hemidiaphragm preparations from Wistar rats.
View Article and Find Full Text PDFAdv Sci (Weinh)
November 2024
Department of Neurology of Second Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
Astrocytes play a crucial role in regulating sleep-wake behavior. However, how astrocytes govern a specific sleep-arousal circuit remains unknown. Here, the authors show that parafacial zone (PZ) astrocytes responded to sleep-wake cycles with state-differential Ca activity, peaking during transitions from sleep to wakefulness.
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