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Meron S, Peleg S, Shenberger Y, Hofmann L, Gevorkyan-Airapetov L, Ruthstein S. Tracking Disordered Extracellular Domains of Membrane Proteins in the Cell with Cu(II)-Based Spin Labels. J Phys Chem B 2024; 128:8908-8914. [PMID: 39231533 PMCID: PMC11421077 DOI: 10.1021/acs.jpcb.4c03676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024]
Abstract
In-cell electron paramagnetic resonance (EPR) spectroscopy experiments provide high-resolution data about conformational changes of proteins within the cell. However, one of the limitations of EPR is the requisite of stable paramagnetic centers in a reducing environment. We recently showed that histidine-rich sites in proteins hold a high affinity to Cu(II) ions complexed with a chelator. Using a chelator prevents the reduction of Cu(II) ions. Moreover, this spin-labeling methodology can be performed within the native cellular environment on any overexpressed protein without protein purification and delivery to the cell. Herein, we use this novel methodology to gain spatial information on the extracellular domain of the human copper transporter, hCtr1. Limited structural information on the transmembrane domain of the human Ctr1 (hCtr1) was obtained using X-ray crystallography and cryo-EM. However, these structures are missing information on the disordered extracellular domains of hCtr1. Extracellular domains are sensing or interacting with the environment outside of the cell and therefore play an essential role in any transmembrane protein. Especially in hCtr1, the extracellular domain functions as a gating mechanism for copper ions. Here, we performed EPR experiments revealing structural information about the extracellular N-terminal domain of the full-length hCtr1 in vitro and in situ in insect cells and cell membrane fragments. The comparison revealed that the extracellular domains of the in situ and native membrane hCtr1 are further apart than the structure of the purified protein. These method-related differences highlight the significance of studying membrane proteins in their native environment.
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Affiliation(s)
- Shelly Meron
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Shahaf Peleg
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Yulia Shenberger
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Lukas Hofmann
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Lada Gevorkyan-Airapetov
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Sharon Ruthstein
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
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2
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Aupič J, Pokorná P, Ruthstein S, Magistrato A. Predicting Conformational Ensembles of Intrinsically Disordered Proteins: From Molecular Dynamics to Machine Learning. J Phys Chem Lett 2024; 15:8177-8186. [PMID: 39093570 DOI: 10.1021/acs.jpclett.4c01544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Intrinsically disordered proteins and regions (IDP/IDRs) are ubiquitous across all domains of life. Characterized by a lack of a stable tertiary structure, IDP/IDRs populate a diverse set of transiently formed structural states that can promiscuously adapt upon binding with specific interaction partners and/or certain alterations in environmental conditions. This malleability is foundational for their role as tunable interaction hubs in core cellular processes such as signaling, transcription, and translation. Tracing the conformational ensemble of an IDP/IDR and its perturbation in response to regulatory cues is thus paramount for illuminating its function. However, the conformational heterogeneity of IDP/IDRs poses several challenges. Here, we review experimental and computational methods devised to disentangle the conformational landscape of IDP/IDRs, highlighting recent computational advances that permit proteome-wide scans of IDP/IDRs conformations. We briefly evaluate selected computational methods using the disordered N-terminal of the human copper transporter 1 as a test case and outline further challenges in IDP/IDRs ensemble prediction.
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Affiliation(s)
- Jana Aupič
- CNR-IOM at International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136 Trieste, Italy
| | - Pavlína Pokorná
- CNR-IOM at International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136 Trieste, Italy
| | - Sharon Ruthstein
- Department of Chemistry, Faculty of Exact Sciences and the Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Alessandra Magistrato
- CNR-IOM at International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136 Trieste, Italy
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3
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Guo J, Sun Y, Liu G. The mechanism of copper transporters in ovarian cancer cells and the prospect of cuproptosis. J Inorg Biochem 2023; 247:112324. [PMID: 37481825 DOI: 10.1016/j.jinorgbio.2023.112324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 07/07/2023] [Accepted: 07/09/2023] [Indexed: 07/25/2023]
Abstract
Copper transporters can not only carry copper (Cu) to maintain the homeostasis of Cu in cells but also transport platinum-based chemotherapy drugs. The effect of copper transporters on chemosensitivity has been demonstrated in a variety of malignancies. In addition, recent studies have reported that copper transporters can act as vectors to induce cuproptosis. Therefore, copper transporters can act on cells through different mechanisms to achieve different purposes. This review mainly describes the current research progress of the intracellular transport mechanism of copper transporters and cuproptosis, and prospects for the application of them in the treatment of ovarian cancer (OC).
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Affiliation(s)
- Jiahuan Guo
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin 300052, China; Key Laboratory of Cancer Prevention and Therapy of Tianjin, Department of Gynecologic Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - Yue Sun
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Guoyan Liu
- Key Laboratory of Cancer Prevention and Therapy of Tianjin, Department of Gynecologic Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China.
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4
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Wort JL, Ackermann K, Giannoulis A, Bode BE. Enhanced sensitivity for pulse dipolar EPR spectroscopy using variable-time RIDME. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 352:107460. [PMID: 37167826 DOI: 10.1016/j.jmr.2023.107460] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 04/03/2023] [Accepted: 04/19/2023] [Indexed: 05/13/2023]
Abstract
Pulse dipolar EPR spectroscopy (PDS) measurements are an important complementary tool in structural biology and are increasingly applied to macromolecular assemblies implicated in human health and disease at physiological concentrations. This requires ever higher sensitivity, and recent advances have driven PDS measurements into the mid-nanomolar concentration regime, though optimization and acquisition of such measurements remains experimentally demanding and time expensive. One important consideration is that constant-time acquisition represents a hard limit for measurement sensitivity, depending on the maximum measured distance. Determining this distance a priori has been facilitated by machine-learning structure prediction (AlphaFold2 and RoseTTAFold) but is often confounded by non-representative behaviour in frozen solution that may mandate multiple rounds of optimization and acquisition. Herein, we endeavour to simultaneously enhance sensitivity and streamline PDS measurement optimization to one-step by benchmarking a variable-time acquisition RIDME experiment applied to CuII-nitroxide and CuII-CuII model systems. Results demonstrate marked sensitivity improvements of both 5- and 6-pulse variable-time RIDME of between 2- and 5-fold over the constant-time analogues.
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Affiliation(s)
- Joshua L Wort
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Angeliki Giannoulis
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Bela E Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland.
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5
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Hirsch M, Hofmann L, Shenberger Y, Gevorkyan-Airapetov L, Ruthstein S. Conformations and Local Dynamics of the CopY Metal Sensor Revealed by EPR Spectroscopy. Biochemistry 2023; 62:797-807. [PMID: 36691693 DOI: 10.1021/acs.biochem.2c00480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Metal transcription factors regulate metal concentrations in eukaryotic and prokaryotic cells. Copper is a metal ion that is being tightly regulated, owing to its dual nature. Whereas copper is an essential nutrient for bacteria, it is also toxic at high concentrations. CopY is a metal-sensitive transcription factor belonging to the copper-responsive repressor family found in Gram-positive bacteria. CopY represses transcription in the presence of Zn(II) ions and initiates transcription in the presence of Cu(I) ions. The complete crystal structure of CopY has not been reported yet, therefore most of the structural information on this protein is based on its similarity to the well-studied MecI protein. In this study, electron paramagnetic resonance (EPR) spectroscopy was used to characterize structural and local dynamical changes in Streptococcus pneumoniae CopY as a function of Zn(II), Cu(I), and DNA binding. We detected different conformations and changes in local dynamics when CopY bound Zn(II), as opposed to Cu(I) ions. Furthermore, we explored the effects of metal ions and DNA on CopY conformation. Our results revealed the sensitivity and selectivity of CopY towards metal ions and provide new insight into the structural mechanism of the CopY transcription factor.
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Affiliation(s)
- Melanie Hirsch
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Lukas Hofmann
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yulia Shenberger
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Sharon Ruthstein
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
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Aupič J, Lapenta F, Janoš P, Magistrato A. Intrinsically disordered ectodomain modulates ion permeation through a metal transporter. Proc Natl Acad Sci U S A 2022; 119:e2214602119. [PMID: 36409899 PMCID: PMC9889885 DOI: 10.1073/pnas.2214602119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/26/2022] [Indexed: 11/22/2022] Open
Abstract
The function of many channels and transporters is enriched by the conformational plasticity of intrinsically disordered regions (IDRs). Copper transporter 1 (Ctr1) is the main entry point for Cu(I) ions in eukaryotes and contains IDRs both at its N-terminal (Nterm) and C-terminal ends. The former delivers copper ions from the extracellular matrix to the selectivity filter in the Ctr1 lumen. However, the molecular mechanism of this process remains elusive due to Nterm's disordered nature. Here, we combine advanced molecular dynamics simulations and circular dichroism experiments to show that Cu(I) ions and a lipidic environment drive the insertion of the Nterm into the Ctr1 selectivity filter, causing its opening. Through a lipid-aided conformational switch of one of the transmembrane helices, the conformational change of the selectivity filter propagates down to the cytosolic gate of Ctr1. Taken together, our results elucidate how conformational variability of IDRs modulates ion transport.
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Affiliation(s)
- Jana Aupič
- National Research Council of Italy - Materials Foundry Istituto Officina dei Materiali c/o International School for Advanced Studies,34136Trieste, Italy
| | - Fabio Lapenta
- Laboratory for Environmental and Life Sciences, University of Nova Gorica,5000Nova Gorica, Slovenia
| | - Pavel Janoš
- National Research Council of Italy - Materials Foundry Istituto Officina dei Materiali c/o International School for Advanced Studies,34136Trieste, Italy
| | - Alessandra Magistrato
- National Research Council of Italy - Materials Foundry Istituto Officina dei Materiali c/o International School for Advanced Studies,34136Trieste, Italy
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Qasem Z, Pavlin M, Ritacco I, Avivi MY, Meron S, Hirsch M, Shenberger Y, Gevorkyan-Airapetov L, Magistrato A, Ruthstein S. Disrupting Cu trafficking as a potential therapy for cancer. Front Mol Biosci 2022; 9:1011294. [PMID: 36299299 PMCID: PMC9589254 DOI: 10.3389/fmolb.2022.1011294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Copper ions play a crucial role in various cellular biological processes. However, these copper ions can also lead to toxicity when their concentration is not controlled by a sophisticated copper-trafficking system. Copper dys-homeostasis has been linked to a variety of diseases, including neurodegeneration and cancer. Therefore, manipulating Cu-trafficking to trigger selective cancer cell death may be a viable strategy with therapeutic benefit. By exploiting combined in silico and experimental strategies, we identified small peptides able to bind Atox1 and metal-binding domains 3-4 of ATP7B proteins. We found that these peptides reduced the proliferation of cancer cells owing to increased cellular copper ions concentration. These outcomes support the idea of harming copper trafficking as an opportunity for devising novel anti-cancer therapies.
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Affiliation(s)
- Zena Qasem
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Matic Pavlin
- National Research Council of Italy (CNR)—Institute of Material (IOM) C/o International School for Advanced Studies (SISSA), Trieste, Italy
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia
| | - Ida Ritacco
- National Research Council of Italy (CNR)—Institute of Material (IOM) C/o International School for Advanced Studies (SISSA), Trieste, Italy
- Department of Chemistry, University of Salerno, Salerno, Italy
| | - Matan Y. Avivi
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Shelly Meron
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Melanie Hirsch
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Yulia Shenberger
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Alessandra Magistrato
- National Research Council of Italy (CNR)—Institute of Material (IOM) C/o International School for Advanced Studies (SISSA), Trieste, Italy
- *Correspondence: Alessandra Magistrato, ; Sharon Ruthstein,
| | - Sharon Ruthstein
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
- *Correspondence: Alessandra Magistrato, ; Sharon Ruthstein,
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8
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Hofmann L, Ruthstein S. EPR Spectroscopy Provides New Insights into Complex Biological Reaction Mechanisms. J Phys Chem B 2022; 126:7486-7494. [PMID: 36137278 PMCID: PMC9549461 DOI: 10.1021/acs.jpcb.2c05235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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In the last 20 years, the use of electron paramagnetic
resonance
(EPR) has made a pronounced and lasting impact in the field of structural
biology. The advantage of EPR spectroscopy over other structural techniques
is its ability to target even minor conformational changes in any
biomolecule or macromolecular complex, independent of its size or
complexity, or whether it is in solution or in the cell during a biological
or chemical reaction. Here, we focus on the use of EPR spectroscopy
to study transmembrane transport and transcription mechanisms. We
discuss experimental and analytical concerns when referring to studies
of two biological reaction mechanisms, namely, transfer of copper
ions by the human copper transporter hCtr1 and the mechanism of action
of the Escherichia coli copper-dependent
transcription factor CueR. Last, we elaborate on future avenues in
the field of EPR structural biology.
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Affiliation(s)
- Lukas Hofmann
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Sharon Ruthstein
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
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