Zinc accumulation in the lumen of cytoplasmic vesicles is one of the mechanisms by which cells can store significant amounts of this essential but potentially toxic biometal. Previous studies had demonstrated reduced vesicular zinc levels in fibroblasts from mutant mice deficient in adaptor protein 3 (AP-3), a complex involved in protein trafficking to late endosomes and lysosomes. We have observed a similar phenotype in the human fibroblastoid cell line, M1, upon small interference RNA-mediated AP-3 knockdown. A survey of the expression and localization of zinc transporter (ZnT) family members identified ZnT2, ZnT3, and ZnT4 as likely mediators of vesicular zinc accumulation in M1 cells. Expression of green fluorescence protein (GFP)-tagged ZnT2 and ZnT3 promoted accumulation of vesicular zinc as visualized using the indicator zinquin. Moreover, GFP-ZnT2 overexpression elicited a significant accumulation of zinc within mature lysosomes, which in untransfected M1 cells contained little or no chelatable zinc, and restored the zinc storage capability of AP-3-deficient cells. These results suggest that ZnT2 can facilitate vesicular zinc accumulation independently of AP-3 function, and validate the M1 fibroblastoid line as a human cell culture system amenable to the study of vesicular zinc regulation using techniques compatible with functional genomic approaches.
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http://dx.doi.org/10.1016/j.yexcr.2007.02.006 | DOI Listing |
J Neurosci
January 2025
Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV, USA.
Synaptically released zinc is a neuronal signaling system that arises from the actions of the presynaptic vesicular zinc transporter protein ZnT3. Mechanisms that regulate the actions of zinc at synapses are of great importance for many aspects of synaptic signaling in the brain. Here, we identify the astrocytic zinc transporter protein ZIP12 as a candidate mechanism that contributes to zinc clearance at cortical synapses.
View Article and Find Full Text PDFPLoS Biol
November 2024
Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Institutes of Biomedical Sciences, Fudan University, Shanghai, China.
The prevalent itching condition associated with aging, historically referred to as senile pruritus, diminishes quality of life. Despite its impact, effective treatments remain elusive, largely due to an incomplete understanding of its pathological cause. In this study, we reveal a subset of dorsal root ganglion neurons enriched with Zn2+ that express the vesicular Zn2+ transporter TMEM163.
View Article and Find Full Text PDFJ Neurochem
October 2024
Laboratory of Neurobiology, Max-Planck-Institute for Biophysical Chemistry and University of Göttingen, Göttinge, Germany.
The heterotrimeric G-protein αo subunit is ubiquitously expressed in the CNS as two splice variants Gα and Gα, regulating various brain functions. Here, we investigated the effect of single Gα, Gα, and double Gα knockout on the postnatal development of the murine mossy fiber tract, a central pathway of the hippocampal connectivity circuit. The size of the hippocampal synaptic termination fields covered by mossy fiber boutons together with various fiber length parameters of the tract was analyzed by immunohistochemical staining of the vesicular Zinc transporter 3 (ZnT3) or Synaptoporin at postnatal days 2, 4, 8, 12, 16, and in the adult.
View Article and Find Full Text PDFbioRxiv
October 2024
Department of Microbiology & Immunology, Columbia University Irving Medical Center, NY, USA.
The genetic basis of resistance to quinine (QN), a drug used to treat severe malaria, has long been enigmatic. To gain further insight, we used FRG-NOD human liver-chimeric mice to conduct a genetic cross between QN-sensitive and QN-resistant parasites, which also differ in their susceptibility to chloroquine (CQ). By applying different selective conditions to progeny pools prior to cloning, we recovered 120 unique recombinant progeny.
View Article and Find Full Text PDFAutophagy
January 2025
Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA, USA.
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