Copper Transporter 1 (CTR1) is a homotrimeric membrane protein providing the main route of copper transport into eukaryotic cells from the extracellular milieu. Its N-terminal extracellular domain, rich in His and Met residues, is considered responsible for directing copper into the transmembrane channel. Most of vertebrate CTR1 proteins contain the His residue in position three from N-terminus, creating a well-known Amino Terminal Cu(II)- and Ni(II)-Binding (ATCUN) site. CTR1 from humans, primates and many other species contains the Met-Asp-His (MDH) sequence, while some rodents including mouse have the Met-Asn-His (MNH) N-terminal sequence. CTR1 is thought to collect Cu(II) ions from blood copper transport proteins, including albumin, but previous reports indicated that the affinity of N-terminal peptide/domain of CTR1 is significantly lower than that of albumin, casting serious doubt on this aspect of CTR1 function. Using potentiometry and spectroscopic techniques we demonstrated that MDH-amide, a tripeptide model of human CTR1 N-terminus, binds Cu(II) with K of 1.3 × 10 M at pH 7.4, ~13 times stronger than Human Serum Albumin (HSA), and MNH-amide is even stronger, K of 3.2 × 10 M at pH 7.4. These results indicate that the N-terminus of CTR1 may serve as intermediate binding site during Cu(II) transfer from blood copper carriers to the transporter. MDH-amide, but not MNH-amide also forms a low abundance complex with non-ATCUN coordination involving the Met amine, His imidazole and Asp carboxylate. This species might assist Cu(II) relay down the peptide chain or its reduction to Cu(I), both steps necessary for the CTR1 function.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jinorgbio.2018.01.011 | DOI Listing |
Mol Biol Cell
January 2025
Department of Cell Biology, Emory University, 615 Michael St, Atlanta, GA, USA, 30322.
Rare inherited diseases caused by mutations in the copper transporters (CTR1) or induce copper deficiency in the brain, causing seizures and neurodegeneration in infancy through poorly understood mechanisms. Here, we used multiple model systems to characterize the molecular mechanisms by which neuronal cells respond to copper deficiency. Targeted deletion of CTR1 in neuroblastoma cells produced copper deficiency that produced a metabolic shift favoring glycolysis over oxidative phosphorylation.
View Article and Find Full Text PDFBiomolecules
January 2025
Department of Chemistry and Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
Ctr1 is a membrane-spanning homotrimer that facilitates copper uptake in eukaryotic cells with high affinity. While structural details of the transmembrane domain of human Ctr1 have been elucidated using X-ray crystallography and cryo-EM, the transfer mechanisms of copper and the conformational changes that control the gating mechanism remain poorly understood. The role of the extracellular N-terminal domains is particularly unclear due to the absence of a high-resolution structure of the full-length hCtr1 protein and limited biochemical and biophysical characterization of the transporter in solution and in cell.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Hematology, Zhongda Hospital, Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China.
SPT5 exhibits versatile functions in RNA Pol II promoter proximal pausing, pause release, and elongation in metazoans. However, the mechanism underlying the functional switch of SPT5 during early elongation has not been fully understood. Here, we report that the phosphorylation site-rich domain (PRD)/CTR1 and the prion-like domain (PLD)/CTR2, which are situated adjacent to each other within the C-terminal repeat (CTR) in SPT5, play pivotal roles in Pol II pausing and elongation, respectively.
View Article and Find Full Text PDFBiochem Biophys Res Commun
February 2025
Department of Bioscience, Tokyo University of Agriculture, Tokyo, 156-8502, Japan. Electronic address:
Plant responses to the water environment are mediated by ethylene (submergence response) and abscisic acid (ABA, drought response). Ethylene is perceived by a family of histidine kinase receptors (ETR-HKs), which regulate the activity of the downstream B3 Raf-like (RAF) kinase CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) in an ethylene-dependent manner. We previously demonstrated in the moss Physcomitrium patens that SNF1-related protein kinase 2 (SnRK2), an essential kinase in osmostress responses in land plants, is activated by the B3-RAF kinase ARK, which is also regulated by ETR-HKs in an ABA- and osmostress-dependent manner.
View Article and Find Full Text PDFLife Sci
January 2025
Department of Cardiology, Cardiac Arrhythmia Center, Affiliated Hospital of Nantong University, Nantong 226001, China. Electronic address:
Doxorubicin (DOX), a chemotherapeutic agent utilized in the management of cancer, provokes cardiotoxicity although effective remedy is lacking. Given that DOX provokes oxidative stress and cell death in cardiomyocytes, this study evaluated the possible involvement of cuproptosis, a newly identified form of cell death, in DOX-instigated cardiac remodeling and contractile dysfunction, alongside the impact of the heavy metal scavenger metallothionein (MT) on DOX cardiomyopathy. Cardiac-specific MT transgenic and wild-type (WT) mice were treated with DOX (5 mg/kg/wk.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!