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Holehouse AS, Kragelund BB. The molecular basis for cellular function of intrinsically disordered protein regions. Nat Rev Mol Cell Biol 2024; 25:187-211. [PMID: 37957331 DOI: 10.1038/s41580-023-00673-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2023] [Indexed: 11/15/2023]
Abstract
Intrinsically disordered protein regions exist in a collection of dynamic interconverting conformations that lack a stable 3D structure. These regions are structurally heterogeneous, ubiquitous and found across all kingdoms of life. Despite the absence of a defined 3D structure, disordered regions are essential for cellular processes ranging from transcriptional control and cell signalling to subcellular organization. Through their conformational malleability and adaptability, disordered regions extend the repertoire of macromolecular interactions and are readily tunable by their structural and chemical context, making them ideal responders to regulatory cues. Recent work has led to major advances in understanding the link between protein sequence and conformational behaviour in disordered regions, yet the link between sequence and molecular function is less well defined. Here we consider the biochemical and biophysical foundations that underlie how and why disordered regions can engage in productive cellular functions, provide examples of emerging concepts and discuss how protein disorder contributes to intracellular information processing and regulation of cellular function.
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Affiliation(s)
- Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO, USA.
- Center for Biomolecular Condensates, Washington University in St Louis, St Louis, MO, USA.
| | - Birthe B Kragelund
- REPIN, Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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2
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How phosphorylation impacts intrinsically disordered proteins and their function. Essays Biochem 2022; 66:901-913. [PMID: 36350035 PMCID: PMC9760426 DOI: 10.1042/ebc20220060] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 11/10/2022]
Abstract
Phosphorylation is the most common post-translational modification (PTM) in eukaryotes, occurring particularly frequently in intrinsically disordered proteins (IDPs). These proteins are highly flexible and dynamic by nature. Thus, it is intriguing that the addition of a single phosphoryl group to a disordered chain can impact its function so dramatically. Furthermore, as many IDPs carry multiple phosphorylation sites, the number of possible states increases, enabling larger complexities and novel mechanisms. Although a chemically simple and well-understood process, the impact of phosphorylation on the conformational ensemble and molecular function of IDPs, not to mention biological output, is highly complex and diverse. Since the discovery of the first phosphorylation site in proteins 75 years ago, we have come to a much better understanding of how this PTM works, but with the diversity of IDPs and their capacity for carrying multiple phosphoryl groups, the complexity grows. In this Essay, we highlight some of the basic effects of IDP phosphorylation, allowing it to serve as starting point when embarking on studies into this topic. We further describe how recent complex cases of multisite phosphorylation of IDPs have been instrumental in widening our view on the effect of protein phosphorylation. Finally, we put forward perspectives on the phosphorylation of IDPs, both in relation to disease and in context of other PTMs; areas where deep insight remains to be uncovered.
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Kohno T, Kojima T. Atypical Macropinocytosis Contributes to Malignant Progression: A Review of Recent Evidence in Endometrioid Endometrial Cancer Cells. Cancers (Basel) 2022; 14:cancers14205056. [PMID: 36291839 PMCID: PMC9599675 DOI: 10.3390/cancers14205056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/01/2022] [Accepted: 10/13/2022] [Indexed: 11/24/2022] Open
Abstract
Simple Summary A novel type of macropinocytosis has been identified as a trigger for the malignant progression of endometrial cancer. Transiently reducing epithelial barrier homeostasis leads to macropinocytosis by splitting between adjacent cells in endometrioid endometrial cancer. Macropinocytosis causes morphological changes in well-differentiated to poorly differentiated cancer cells. Inhibition of macropinocytosis promotes a persistent dormant state in the intrinsic KRAS-mutated cancer cell line Sawano. This review focuses on the mechanisms of atypical macropinocytosis and its effects on cellular function, and it describes the physiological processes involved in inducing resting conditions in endometrioid endometrial cancer cells. Abstract Macropinocytosis is an essential mechanism for the non-specific uptake of extracellular fluids and solutes. In recent years, additional functions have been identified in macropinocytosis, such as the intracellular introduction pathway of drugs, bacterial and viral infection pathways, and nutritional supplement pathway of cancer cells. However, little is known about the changes in cell function after macropinocytosis. Recently, it has been reported that macropinocytosis is essential for endometrial cancer cells to initiate malignant progression in a dormant state. Macropinocytosis is formed by a temporary split of adjacent bicellular junctions of epithelial sheets, rather than from the apical surface or basal membrane, as a result of the transient reduction of tight junction homeostasis. This novel type of macropinocytosis has been suggested to be associated with the malignant pathology of endometriosis and endometrioid endometrial carcinoma. This review outlines the induction of malignant progression of endometrial cancer cells by macropinocytosis based on a new mechanism and the potential preventive mechanism of its malignant progression.
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Gong YY, Shao H, Li Y, Brafford P, Stine ZE, Sun J, Felsher DW, Orange JS, Albelda SM, Dang CV. Na +/H +-exchanger 1 enhances antitumor activity of engineered NK-92 natural killer cells. CANCER RESEARCH COMMUNICATIONS 2022; 2:842-856. [PMID: 36380966 PMCID: PMC9648415 DOI: 10.1158/2767-9764.crc-22-0270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 06/16/2023]
Abstract
Adoptive cell transfer (ACT) immunotherapy has remarkable efficacy against some hematological malignancies. However, its efficacy in solid tumors is limited by the adverse tumor microenvironment (TME) conditions, most notably that acidity inhibits T and natural killer (NK) cell mTOR complex 1 (mTORC1) activity and impairs cytotoxicity. In several reported studies, systemic buffering of tumor acidity enhanced the efficacy of immune checkpoint inhibitors. Paradoxically, we found in a c-Myc-driven hepatocellular carcinoma model that systemic buffering increased tumor mTORC1 activity, negating inhibition of tumor growth by anti-PD1 treatment. Therefore, in this proof-of-concept study, we tested the metabolic engineering of immune effector cells to mitigate the inhibitory effect of tumor acidity while avoiding side effects associated with systemic buffering. We first overexpressed an activated RHEB in the human NK cell line NK-92, thereby rescuing acid-blunted mTORC1 activity and enhancing cytolytic activity. Then, to directly mitigate the effect of acidity, we ectopically expressed acid extruder proteins. Whereas ectopic expression of carbonic anhydrase IX (CA9) moderately increased mTORC1 activity, it did not enhance effector function. In contrast, overexpressing a constitutively active Na+/H+-exchanger 1 (NHE1; SLC9A1) in NK-92 did not elevate mTORC1 but enhanced degranulation, target engagement, in vitro cytotoxicity, and in vivo antitumor activity. Our findings suggest the feasibility of overcoming the inhibitory effect of the TME by metabolically engineering immune effector cells, which can enhance ACT for better efficacy against solid tumors.
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Affiliation(s)
- Yao-Yu Gong
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Yu Li
- Department of Pediatrics, Columbia University Medical Center, New York, New York
| | | | | | - Jing Sun
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dean W. Felsher
- Division of Oncology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Jordan S. Orange
- Department of Pediatrics, Columbia University Medical Center, New York, New York
| | - Steven M. Albelda
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chi V. Dang
- The Wistar Institute, Philadelphia, Pennsylvania
- Ludwig Institute for Cancer Research, New York, New York
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5
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Karmazyn M, Pierce GN, Fliegel L. The Remaining Conundrum of the Role of the Na +/H + Exchanger Isoform 1 (NHE1) in Cardiac Physiology and Pathology: Can It Be Rectified? Rev Cardiovasc Med 2022; 23:284. [PMID: 39076631 PMCID: PMC11266974 DOI: 10.31083/j.rcm2308284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/29/2022] [Accepted: 07/08/2022] [Indexed: 07/31/2024] Open
Abstract
The mammalian Na + /H + exchanger (NHE) is a family of ubiquitous membrane proteins present in humans. Isoform one (NHE1) is present on the plasma membrane and regulates intracellular pH by removal of one intracellular proton in exchange for one extracellular sodium thus functioning as an electroneutral process. Human NHE1 has a 500 amino acid membrane domain plus a C-terminal 315 amino acid, regulatory cytosolic tail. It is regulated through a cytosolic regulatory C-terminal tail which is subject to phosphorylation and is modulated by proteins and lipids. Substantial evidence has implicated NHE1 activity in both myocardial ischemia and reperfusion damage and myocardial remodeling resulting in heart failure. Experimental data show excellent cardioprotection with NHE1 inhibitors although results from clinical results have been mixed. In cardiac surgery patients receiving the NHE1 inhibitor cariporide, subgroups showed beneficial effects of treatment. However, in one trial this was associated with a significantly increased incidence of ischemic strokes. This likely reflected both inappropriate dosing regimens as well as overly high drug doses. We suggest that further progress towards NHE1 inhibition as a treatment for cardiovascular disease is warranted through the development of novel compounds to inhibit NHE1 that are structurally different than those previously used in compromised clinical trials. Some novel pyrazinoyl guanidine inhibitors of NHE1 are already in development and the recent elucidation of the three-dimensional structure of the NHE1 protein and identity of the inhibitor binding site may facilitate development. An alternative approach may also be to control the endogenous regulation of activity of NHE1, which is activated in disease.
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Affiliation(s)
- Morris Karmazyn
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Grant N. Pierce
- Institute of Cardiovascular Sciences, Albrechtsen Research Centre, St. Boniface Hospital, and Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
| | - Larry Fliegel
- Department of Biochemistry, University Alberta, Edmonton, AB T6G 2H7, Canada
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Poet M, Doyen D, Van Obberghen E, Jarretou G, Bouret Y, Counillon L. How Does Our Knowledge on the Na+/H+ Exchanger NHE1 Obtained by Biochemical and Molecular Analyses Keep up With Its Recent Structure Determination? Front Physiol 2022; 13:907587. [PMID: 35910559 PMCID: PMC9334524 DOI: 10.3389/fphys.2022.907587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/06/2022] [Indexed: 11/23/2022] Open
Abstract
Na+/H+ exchangers are membrane transporters conserved in all living systems and therefore are assumed to be amongst the most ancestral molecular devices that equipped the first protocells. Following the cloning and sequencing of its gene, the mammalian NHE1, that regulates pH and volume in all cells, has been thoroughly scrutinized by molecular and biochemical analyses. Those gave a series of crucial clues concerning its topology, dimeric organization, pharmacological profile, regulation, and the role of key amino acids. Recently thanks to cryogenic Electron Microscopy (Cryo-EM) the long-awaited molecular structures have been revealed. With this information in mind we will challenge the robustness of the earlier conclusions and highlight how the new information enriches our understanding of this key cellular player. At the mechanistic level, we will pinpoint how the NHE1 3D structures reveal that the previously identified amino acids and regions are organized to coordinate transported cations, and shape the allosteric transition that makes NHE1 able to sense intracellular pH and be regulated by signaling pathways.
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Affiliation(s)
- Mallorie Poet
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - Denis Doyen
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
- Centre Hospitalier Universitaire de Nice, Nice, France
| | - Emmanuel Van Obberghen
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
- Centre Hospitalier Universitaire de Nice, Nice, France
| | - Gisèle Jarretou
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - Yann Bouret
- Université Côte d’Azur, CNRS, Institut de Physique de Nice (INPHYNI), Valbonne, France
| | - Laurent Counillon
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
- *Correspondence: Laurent Counillon,
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7
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Li X, Buckley B, Stoletov K, Jing Y, Ranson M, Lewis JD, Kelso M, Fliegel L. Roles of the Na +/H + Exchanger Isoform 1 and Urokinase in Prostate Cancer Cell Migration and Invasion. Int J Mol Sci 2021; 22:ijms222413263. [PMID: 34948058 PMCID: PMC8705693 DOI: 10.3390/ijms222413263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 01/06/2023] Open
Abstract
Prostate cancer is a leading cause of cancer-associated deaths in men over 60 years of age. Most patients are killed by tumor metastasis. Recent evidence has implicated a role of the tumor microenvironment and urokinase plasminogen activator (uPA) in cancer cell migration, invasion, and metastasis. Here, we examine the role of the Na+/H+ exchanger isoform 1 (NHE1) and uPA in DU 145 prostate cancer cell migration and colony formation. Knockout of NHE1 reduced cell migration. The effects of a series of novel NHE1/uPA hexamethylene-amiloride-based inhibitors with varying efficacy towards NHE1 and uPA were examined on prostate cancer cells. Inhibition of NHE1-alone, or with inhibitors combining NHE1 or uPA inhibition-generally did not prevent prostate cancer cell migration. However, uPA inhibition-but not NHE1 inhibition-prevented anchorage-dependent colony formation. Application of inhibitors at concentrations that only saturate uPA inhibition decreased tumor invasion in vivo. The results suggest that while knockout of NHE1 affects cell migration, these effects are not due to NHE1-dependent proton translocation. Additionally, while neither NHE1 nor uPA activity was critical in cell migration, only uPA activity appeared to be critical in anchorage-dependent colony formation of DU 145 prostate cancer cells and invasion in vivo.
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Affiliation(s)
- Xiuju Li
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (Y.J.)
| | - Benjamin Buckley
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (B.B.); (M.R.); (M.K.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Konstantin Stoletov
- Department of Oncology, University of Alberta, Edmonton, AB T6G 2H7, Canada; (K.S.); (J.D.L.)
| | - Yang Jing
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (Y.J.)
| | - Marie Ranson
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (B.B.); (M.R.); (M.K.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - John D. Lewis
- Department of Oncology, University of Alberta, Edmonton, AB T6G 2H7, Canada; (K.S.); (J.D.L.)
| | - Mike Kelso
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (B.B.); (M.R.); (M.K.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (Y.J.)
- Correspondence: ; Tel.: +1-780-492-1848
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8
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Amino Acids 785, 787 of the Na +/H + Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation. Int J Mol Sci 2021; 22:ijms222111349. [PMID: 34768780 PMCID: PMC8583816 DOI: 10.3390/ijms222111349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 11/30/2022] Open
Abstract
The mammalian Na+/H+ exchanger isoform 1 (NHE1) is a plasma membrane protein ubiquitously present in humans. It regulates intracellular pH by removing an intracellular proton in exchange for an extracellular sodium. It consists of a 500 amino acid membrane domain plus a 315 amino acid, regulatory cytosolic tail. Here, we investigated the effect of mutation of two amino acids of the regulatory tail, Ser785 and Ser787, that were similar in location and context to two amino acids of the Arabidopsis Na+/H+ exchanger SOS1. Mutation of these two amino acids to either Ala or phosphomimetic Glu did not affect surface targeting but led to a slight reduction in the level of protein expressed. The activity of the NHE1 protein was reduced in the phosphomimetic mutations and the effect was due to a decrease in Vmax activity. The Ser to Glu mutations also caused a change in the apparent molecular weight of both the full-length protein and of the cytosolic tail of NHE1. A conformational change in this region was indicated by differential trypsin sensitivity. We also found that a peptide containing amino acids 783–790 bound to several more proximal regions of the NHE1 tail in in vitro protein interaction experiments. The results are the first characterization of these two amino acids and show that they have significant effects on enzyme kinetics and the structure of the NHE1 protein.
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Abstract
Flexibility in complexes between intrinsically disordered proteins and folded ligands is widespread in nature. However, timescales and spatial amplitudes of such dynamics remained unexplored for most systems. Our results show that the disordered cytoplasmic tail of the cell adhesion protein E-cadherin diffuses across the entire surface of its folded binding partner β-catenin at fast submillisecond timescales. The nanometer amplitude of these motions could allow kinases to access their recognition motifs without requiring a dissociation of the complex. We expect that the rugged energy landscape found in the E-cadherin/β-catenin complex is a defining feature of dynamic and partially disordered protein complexes. Intrinsically disordered proteins often form dynamic complexes with their ligands. Yet, the speed and amplitude of these motions are hidden in classical binding kinetics. Here, we directly measure the dynamics in an exceptionally mobile, high-affinity complex. We show that the disordered tail of the cell adhesion protein E-cadherin dynamically samples a large surface area of the protooncogene β-catenin. Single-molecule experiments and molecular simulations resolve these motions with high resolution in space and time. Contacts break and form within hundreds of microseconds without a dissociation of the complex. The energy landscape of this complex is rugged with many small barriers (3 to 4 kBT) and reconciles specificity, high affinity, and extreme disorder. A few persistent contacts provide specificity, whereas unspecific interactions boost affinity.
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10
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Kohno T, Konno T, Kikuchi S, Kondoh M, Kojima T. Translocation of LSR from tricellular corners causes macropinocytosis at cell-cell interface as a trigger for breaking out of contact inhibition. FASEB J 2021; 35:e21742. [PMID: 34403506 DOI: 10.1096/fj.202100299r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 12/29/2022]
Abstract
Withdrawal from contact inhibition is necessary for epithelial cancer precursor cells to initiate cell growth and motility. Nevertheless, little is understood about the mechanism for the sudden initiation of cell growth under static conditions. We focused on cellular junctions as one region where breaking out of contact inhibition occurs. In well-differentiated endometrial cancer cells, Sawano, the ligand administration for tricellular tight junction protein LSR, which transiently decreased the robust junction property, caused an abrupt increase in cell motility and consequent excessive multilayered cell growth despite being under contact inhibition conditions. We observed that macropinocytosis essentially and temporarily occurred as an antecedent event for the above process at intercellular junctions without disruption of the junction apparatus but not at the apical plasma membrane. Collectively, we concluded that the formation of macropinocytosis, which is derived from tight junction-mediated signaling, was triggered for the initiation of cell growth in static precancerous epithelium.
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Affiliation(s)
- Takayuki Kohno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, Japan
| | - Takumi Konno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, Japan
| | - Shin Kikuchi
- Department of Anatomy, Sapporo Medical University, Sapporo, Japan
| | - Masuo Kondoh
- Drug Innovation Center, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Takashi Kojima
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, Japan
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11
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Lindorff-Larsen K, Kragelund BB. On the potential of machine learning to examine the relationship between sequence, structure, dynamics and function of intrinsically disordered proteins. J Mol Biol 2021; 433:167196. [PMID: 34390736 DOI: 10.1016/j.jmb.2021.167196] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 11/29/2022]
Abstract
Intrinsically disordered proteins (IDPs) constitute a broad set of proteins with few uniting and many diverging properties. IDPs-and intrinsically disordered regions (IDRs) interspersed between folded domains-are generally characterized as having no persistent tertiary structure; instead they interconvert between a large number of different and often expanded structures. IDPs and IDRs are involved in an enormously wide range of biological functions and reveal novel mechanisms of interactions, and while they defy the common structure-function paradigm of folded proteins, their structural preferences and dynamics are important for their function. We here discuss open questions in the field of IDPs and IDRs, focusing on areas where machine learning and other computational methods play a role. We discuss computational methods aimed to predict transiently formed local and long-range structure, including methods for integrative structural biology. We discuss the many different ways in which IDPs and IDRs can bind to other molecules, both via short linear motifs, as well as in the formation of larger dynamic complexes such as biomolecular condensates. We discuss how experiments are providing insight into such complexes and may enable more accurate predictions. Finally, we discuss the role of IDPs in disease and how new methods are needed to interpret the mechanistic effects of genomic variants in IDPs.
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Affiliation(s)
- Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen. Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen. Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
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12
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Sjøgaard-Frich LM, Prestel A, Pedersen ES, Severin M, Kristensen KK, Olsen JG, Kragelund BB, Pedersen SF. Dynamic Na +/H + exchanger 1 (NHE1) - calmodulin complexes of varying stoichiometry and structure regulate Ca 2+-dependent NHE1 activation. eLife 2021; 10:60889. [PMID: 33655882 PMCID: PMC8009664 DOI: 10.7554/elife.60889] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 03/01/2021] [Indexed: 11/25/2022] Open
Abstract
Calmodulin (CaM) engages in Ca2+-dependent interactions with numerous proteins, including a still incompletely understood physical and functional interaction with the human Na+/H+-exchanger NHE1. Using nuclear magnetic resonance (NMR) spectroscopy, isothermal titration calorimetry, and fibroblasts stably expressing wildtype and mutant NHE1, we discovered multiple accessible states of this functionally important complex existing in different NHE1:CaM stoichiometries and structures. We determined the NMR solution structure of a ternary complex in which CaM links two NHE1 cytosolic tails. In vitro, stoichiometries and affinities could be tuned by variations in NHE1:CaM ratio and calcium ([Ca2+]) and by phosphorylation of S648 in the first CaM-binding α-helix. In cells, Ca2+-CaM-induced NHE1 activity was reduced by mimicking S648 phosphorylation and by mutation of the first CaM-binding α-helix, whereas it was unaffected by inhibition of Akt, one of several kinases phosphorylating S648. Our results demonstrate a diversity of NHE1:CaM interaction modes and suggest that CaM may contribute to NHE1 dimerization and thereby augment NHE1 regulation. We propose that a similar structural diversity is of relevance to many other CaM complexes.
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Affiliation(s)
- Lise M Sjøgaard-Frich
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Prestel
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Emilie S Pedersen
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Marc Severin
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Kølby Kristensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Johan G Olsen
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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13
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Structural Insights into the Interaction of the Intrinsically Disordered Co-activator TIF2 with Retinoic Acid Receptor Heterodimer (RXR/RAR). J Mol Biol 2021; 433:166899. [PMID: 33647291 DOI: 10.1016/j.jmb.2021.166899] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/02/2021] [Accepted: 02/22/2021] [Indexed: 12/19/2022]
Abstract
Retinoic acid receptors (RARs) and retinoid X receptors (RXRs) form heterodimers that activate target gene transcription by recruiting co-activator complexes in response to ligand binding. The nuclear receptor (NR) co-activator TIF2 mediates this recruitment by interacting with the ligand-binding domain (LBD) of NRs trough the nuclear receptor interaction domain (TIF2NRID) containing three highly conserved α-helical LxxLL motifs (NR-boxes). The precise binding mode of this domain to RXR/RAR is not clear due to the disordered nature of TIF2. Here we present the structural characterization of TIF2NRID by integrating several experimental (NMR, SAXS, Far-UV CD, SEC-MALS) and computational data. Collectively, the data are in agreement with a largely disordered protein with partially structured regions, including the NR-boxes and their flanking regions, which are evolutionary conserved. NMR and X-ray crystallographic data on TIF2NRID in complex with RXR/RAR reveal a multisite binding of the three NR-boxes as well as an active role of their flanking regions in the interaction.
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14
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Wigington CP, Roy J, Damle NP, Yadav VK, Blikstad C, Resch E, Wong CJ, Mackay DR, Wang JT, Krystkowiak I, Bradburn DA, Tsekitsidou E, Hong SH, Kaderali MA, Xu SL, Stearns T, Gingras AC, Ullman KS, Ivarsson Y, Davey NE, Cyert MS. Systematic Discovery of Short Linear Motifs Decodes Calcineurin Phosphatase Signaling. Mol Cell 2020; 79:342-358.e12. [PMID: 32645368 DOI: 10.1016/j.molcel.2020.06.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 03/24/2020] [Accepted: 05/26/2020] [Indexed: 12/17/2022]
Abstract
Short linear motifs (SLiMs) drive dynamic protein-protein interactions essential for signaling, but sequence degeneracy and low binding affinities make them difficult to identify. We harnessed unbiased systematic approaches for SLiM discovery to elucidate the regulatory network of calcineurin (CN)/PP2B, the Ca2+-activated phosphatase that recognizes LxVP and PxIxIT motifs. In vitro proteome-wide detection of CN-binding peptides, in vivo SLiM-dependent proximity labeling, and in silico modeling of motif determinants uncovered unanticipated CN interactors, including NOTCH1, which we establish as a CN substrate. Unexpectedly, CN shows SLiM-dependent proximity to centrosomal and nuclear pore complex (NPC) proteins-structures where Ca2+ signaling is largely uncharacterized. CN dephosphorylates human and yeast NPC proteins and promotes accumulation of a nuclear transport reporter, suggesting conserved NPC regulation by CN. The CN network assembled here provides a resource to investigate Ca2+ and CN signaling and demonstrates synergy between experimental and computational methods, establishing a blueprint for examining SLiM-based networks.
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Affiliation(s)
| | - Jagoree Roy
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Nikhil P Damle
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Vikash K Yadav
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden
| | - Cecilia Blikstad
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden
| | - Eduard Resch
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Branch for Translational Medicine and Pharmacology TMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Cassandra J Wong
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
| | - Douglas R Mackay
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Jennifer T Wang
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Izabella Krystkowiak
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | | | | | - Su Hyun Hong
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Malika Amyn Kaderali
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Shou-Ling Xu
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Tim Stearns
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, M5S 3H7 ON, Canada
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Ylva Ivarsson
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden
| | - Norman E Davey
- Division of Cancer Biology, The Institute of Cancer Research, 237 Fullham Road, London SW3 6JB, UK
| | - Martha S Cyert
- Department of Biology, Stanford University, Stanford, CA, USA.
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15
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Julien M, Bouguechtouli C, Alik A, Ghouil R, Zinn-Justin S, Theillet FX. Multiple Site-Specific Phosphorylation of IDPs Monitored by NMR. Methods Mol Biol 2020; 2141:793-817. [PMID: 32696390 DOI: 10.1007/978-1-0716-0524-0_41] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In line with their high accessibility, disordered proteins are exquisite targets of kinases. Eukaryotic organisms use the so-called intrinsically disordered proteins (IDPs) or intrinsically disordered regions of proteins (IDRs) as molecular switches carrying intracellular information tuned by reversible phosphorylation schemes. Solvent-exposed serines and threonines are abundant in IDPs, and, consistently, kinases often modify disordered regions of proteins at multiple sites. In this context, nuclear magnetic resonance (NMR) spectroscopy provides quantitative, residue-specific information that permits mapping of phosphosites and monitoring of their individual kinetics. Hence, NMR monitoring emerges as an in vitro approach, complementary to mass-spectrometry or immuno-blotting, to characterize IDP phosphorylation comprehensively. Here, we describe in detail generic protocols for carrying out NMR monitoring of IDP phosphorylation, and we provide a number of practical insights that improve handiness and reproducibility of this method.
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Affiliation(s)
- Manon Julien
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France
| | - Chafiaa Bouguechtouli
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France
| | - Ania Alik
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France
| | - Rania Ghouil
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France
| | - Sophie Zinn-Justin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France
| | - François-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France.
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16
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Schuler B, Borgia A, Borgia MB, Heidarsson PO, Holmstrom ED, Nettels D, Sottini A. Binding without folding - the biomolecular function of disordered polyelectrolyte complexes. Curr Opin Struct Biol 2019; 60:66-76. [PMID: 31874413 DOI: 10.1016/j.sbi.2019.12.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/29/2019] [Accepted: 12/05/2019] [Indexed: 12/16/2022]
Abstract
Recent evidence shows that oppositely charged intrinsically disordered proteins (IDPs) can form high-affinity complexes that involve neither the formation of secondary or tertiary structure nor site-specific interactions between individual residues. Similar electrostatically dominated interactions have also been identified for positively charged IDPs binding to nucleic acids. These highly disordered polyelectrolyte complexes constitute an extreme case within the spectrum of biomolecular interactions involving disorder. Such interactions are likely to be widespread, since sequence analysis predicts proteins with highly charged disordered regions to be surprisingly numerous. Here, we summarize the insights that have emerged from the highly disordered polyelectrolyte complexes identified so far, and we highlight recent developments and future challenges in (i) establishing models for the underlying highly dynamic structural ensembles, (ii) understanding the novel binding mechanisms associated with them, and (iii) identifying the functional consequences.
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Affiliation(s)
- Benjamin Schuler
- Department of Biochemistry, University of Zurich, Switzerland; Department of Physics, University of Zurich, Switzerland.
| | - Alessandro Borgia
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Madeleine B Borgia
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Pétur O Heidarsson
- Department of Biochemistry, Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland
| | - Erik D Holmstrom
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside, Lawrence, KS 66045, USA; Department of Chemistry, University of Kansas, 1200 Sunnyside, Lawrence, KS 66045, USA
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Switzerland
| | - Andrea Sottini
- Department of Biochemistry, University of Zurich, Switzerland
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17
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Hendus-Altenburger R, Fernandes CB, Bugge K, Kunze MBA, Boomsma W, Kragelund BB. Random coil chemical shifts for serine, threonine and tyrosine phosphorylation over a broad pH range. JOURNAL OF BIOMOLECULAR NMR 2019; 73:713-725. [PMID: 31598803 PMCID: PMC6875518 DOI: 10.1007/s10858-019-00283-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/30/2019] [Indexed: 05/26/2023]
Abstract
Phosphorylation is one of the main regulators of cellular signaling typically occurring in flexible parts of folded proteins and in intrinsically disordered regions. It can have distinct effects on the chemical environment as well as on the structural properties near the modification site. Secondary chemical shift analysis is the main NMR method for detection of transiently formed secondary structure in intrinsically disordered proteins (IDPs) and the reliability of the analysis depends on an appropriate choice of random coil model. Random coil chemical shifts and sequence correction factors were previously determined for an Ac-QQXQQ-NH2-peptide series with X being any of the 20 common amino acids. However, a matching dataset on the phosphorylated states has so far only been incompletely determined or determined only at a single pH value. Here we extend the database by the addition of the random coil chemical shifts of the phosphorylated states of serine, threonine and tyrosine measured over a range of pH values covering the pKas of the phosphates and at several temperatures (www.bio.ku.dk/sbinlab/randomcoil). The combined results allow for accurate random coil chemical shift determination of phosphorylated regions at any pH and temperature, minimizing systematic biases of the secondary chemical shifts. Comparison of chemical shifts using random coil sets with and without inclusion of the phosphoryl group, revealed under/over estimations of helicity of up to 33%. The expanded set of random coil values will improve the reliability in detection and quantification of transient secondary structure in phosphorylation-modified IDPs.
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Affiliation(s)
- Ruth Hendus-Altenburger
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
| | - Catarina B Fernandes
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
| | - Katrine Bugge
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
| | - Micha B A Kunze
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
| | - Wouter Boomsma
- Department of Computer Science, University of Copenhagen, Universitetsparken 1, 2100, Copenhagen Ø, Denmark
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark.
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18
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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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19
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Abstract
Phosphorylation is a ubiquitous posttranslational modification that is essential for the regulation of many cellular processes. The human genome consists of more than 200,000 phosphorylation sites, whose phosphorylation is tightly controlled by ≥500 kinases and ~200 phosphatases. Given the large number of phosphorylation sites and the key role phosphorylation plays in regulating cellular processes, it is essential to characterize the impact of phosphorylation on substrate structure, dynamics, and function. However, a major challenge is the large-scale production of phosphorylated proteins in vitro for these structural, functional, and dynamic studies. Here, we describe an efficient protocol used routinely in our laboratory for the production of phosphorylated proteins. We also describe the methods used for identifying, characterizing, and separating the resulting phosphorylated proteins for subsequent studies.
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Affiliation(s)
- Ganesan Senthil Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States.
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20
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Molecular basis for the binding and selective dephosphorylation of Na +/H + exchanger 1 by calcineurin. Nat Commun 2019; 10:3489. [PMID: 31375679 PMCID: PMC6677818 DOI: 10.1038/s41467-019-11391-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/08/2019] [Indexed: 01/26/2023] Open
Abstract
Very little is known about how Ser/Thr protein phosphatases specifically recruit and dephosphorylate substrates. Here, we identify how the Na+/H+-exchanger 1 (NHE1), a key regulator of cellular pH homeostasis, is regulated by the Ser/Thr phosphatase calcineurin (CN). NHE1 activity is increased by phosphorylation of NHE1 residue T779, which is specifically dephosphorylated by CN. While it is known that Ser/Thr protein phosphatases prefer pThr over pSer, we show that this preference is not key to this exquisite CN selectivity. Rather a combination of molecular mechanisms, including recognition motifs, dynamic charge-charge interactions and a substrate interaction pocket lead to selective dephosphorylation of pT779. Our data identify T779 as a site regulating NHE1-mediated cellular acid extrusion and provides a molecular understanding of NHE1 substrate selection by CN, specifically, and how phosphatases recruit specific substrates, generally.
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21
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Lagadic-Gossmann D, Hardonnière K, Mograbi B, Sergent O, Huc L. Disturbances in H + dynamics during environmental carcinogenesis. Biochimie 2019; 163:171-183. [PMID: 31228544 DOI: 10.1016/j.biochi.2019.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 06/16/2019] [Indexed: 12/24/2022]
Abstract
Despite the improvement of diagnostic methods and anticancer therapeutics, the human population is still facing an increasing incidence of several types of cancers. According to the World Health Organization, this growing trend would be partly linked to our environment, with around 20% of cancers stemming from exposure to environmental contaminants, notably chemicals like polycyclic aromatic hydrocarbons (PAHs). PAHs are widespread pollutants in our environment resulting from incomplete combustion or pyrolysis of organic material, and thus produced by both natural and anthropic sources; notably benzo[a]pyrene (B[a]P), i.e. the prototypical molecule of this family, that can be detected in cigarette smoke, diesel exhaust particles, occupational-related fumes, and grilled food. This molecule is a well-recognized carcinogen belonging to group 1 carcinogens. Indeed, it can target the different steps of the carcinogenic process and all cancer hallmarks. Interestingly, H+ dynamics have been described as key parameters for the occurrence of several, if not all, of these hallmarks. However, information regarding the role of such parameters during environmental carcinogenesis is still very scarce. The present review will thus mainly give an overview of the impact of B[a]P on H+ dynamics in liver cells, and will show how such alterations might impact different aspects related to the finely-tuned balance between cell death and survival processes, thereby likely favoring environmental carcinogenesis. In total, the main objective of this review is to encourage further research in this poorly explored field of environmental molecular toxicology.
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Affiliation(s)
- Dominique Lagadic-Gossmann
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France.
| | - Kévin Hardonnière
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France
| | - Baharia Mograbi
- Institute of Research on Cancer and Ageing of Nice (IRCAN), INSERM U1081, CNRS UMR7284, 2. Université de Nice-Sophia Antipolis, Faculté de Médecine, Centre Antoine Lacassagne, Nice, F-06107, France
| | - Odile Sergent
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France
| | - Laurence Huc
- INRA, ToxAlim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
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22
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Structural and Functional Changes in the Na +/H + Exchanger Isoform 1, Induced by Erk1/2 Phosphorylation. Int J Mol Sci 2019; 20:ijms20102378. [PMID: 31091671 PMCID: PMC6566726 DOI: 10.3390/ijms20102378] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/15/2022] Open
Abstract
The human Na+/H+ exchanger isoform 1 (NHE1) is a plasma membrane transport protein that plays an important role in pH regulation in mammalian cells. Because of the generation of protons by intermediary metabolism as well as the negative membrane potential, protons accumulate within the cytosol. Extracellular signal-regulated kinase (ERK)-mediated regulation of NHE1 is important in several human pathologies including in the myocardium in heart disease, as well as in breast cancer as a trigger for growth and metastasis. NHE1 has a N-terminal, a 500 amino acid membrane domain, and a C-terminal 315 amino acid cytosolic domain. The C-terminal domain regulates the membrane domain and its effects on transport are modified by protein binding and phosphorylation. Here, we discuss the physiological regulation of NHE1 by ERK, with an emphasis on the critical effects on structure and function. ERK binds directly to the cytosolic domain at specific binding domains. ERK also phosphorylates NHE1 directly at multiple sites, which enhance NHE1 activity with subsequent downstream physiological effects. The NHE1 cytosolic regulatory tail possesses both ordered and disordered regions, and the disordered regions are stabilized by ERK-mediated phosphorylation at a phosphorylation motif. Overall, ERK pathway mediated phosphorylation modulates the NHE1 tail, and affects the activity, structure, and function of this membrane protein.
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23
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Selenko P. Quo Vadis Biomolecular NMR Spectroscopy? Int J Mol Sci 2019; 20:ijms20061278. [PMID: 30875725 PMCID: PMC6472163 DOI: 10.3390/ijms20061278] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 02/06/2023] Open
Abstract
In-cell nuclear magnetic resonance (NMR) spectroscopy offers the possibility to study proteins and other biomolecules at atomic resolution directly in cells. As such, it provides compelling means to complement existing tools in cellular structural biology. Given the dominance of electron microscopy (EM)-based methods in current structure determination routines, I share my personal view about the role of biomolecular NMR spectroscopy in the aftermath of the revolution in resolution. Specifically, I focus on spin-off applications that in-cell NMR has helped to develop and how they may provide broader and more generally applicable routes for future NMR investigations. I discuss the use of ‘static’ and time-resolved solution NMR spectroscopy to detect post-translational protein modifications (PTMs) and to investigate structural consequences that occur in their response. I argue that available examples vindicate the need for collective and systematic efforts to determine post-translationally modified protein structures in the future. Furthermore, I explain my reasoning behind a Quinary Structure Assessment (QSA) initiative to interrogate cellular effects on protein dynamics and transient interactions present in physiological environments.
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Affiliation(s)
- Philipp Selenko
- Weizmann Institute of Science, Department of Biological Regulation, 234 Herzl Street, Rehovot 76100, Israel.
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24
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Zhang J, Kong X, Wang Z, Gao X, Ge Z, Gu Y, Ye P, Chao Y, Zhu L, Li X, Chen S. AMP-activated protein kinase regulates glycocalyx impairment and macrophage recruitment in response to low shear stress. FASEB J 2019; 33:7202-7212. [PMID: 30860864 DOI: 10.1096/fj.201801869rrr] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Low shear stress (LSS) increases degradation of the endothelial glycocalyx, leading to production of endothelial inflammation and atherosclerosis. However, the underlying mechanisms of how LSS diminishes the endothelial glycocalyx remain unclear. We showed that LSS inactivated AMPK, enhanced Na+-H+ exchanger (NHE)1 activity, and induced glycocalyx degradation. Activation of AMPK prevented LSS-induced NHE1 activity and endothelial glycocalyx impairment. We further identified hyaluronidase 2 (HYAL2) as a mediator of endothelial glycocalyx impairment in HUVECs exposed to LSS. Inactivation of AMPK by LSS up-regulates the activity of HYAL2, which acts downstream of NHE1. We characterized a left common carotid artery partial ligation (PL) model of LSS in C57BL/6 mice. The results showed decreased expression of hyaluronan (HA) in the endothelial glycocalyx and decreased thickness of the endothelial glycocalyx in PL mice. Pharmacological activation of AMPK by ampkinone not only attenuated glycocalyx impairment due to HA degradation but also blocked vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 expression increase and macrophage recruitment in the endothelia of PL mice. Our results revealed that AMPK dephosphorylation induced by LSS activates NHE1 and HYAL2 to promote HA degradation and glycocalyx injury, which may contribute to endothelial inflammatory reaction and macrophage recruitment.-Zhang, J., Kong, X., Wang, Z., Gao, X., Ge, Z., Gu, Y., Ye, P., Chao, Y., Zhu, L., Li, X., Chen, S. AMP-activated protein kinase regulates glycocalyx impairment and macrophage recruitment in response to low shear stress.
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Affiliation(s)
- Junjie Zhang
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Xiangquan Kong
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Zhimei Wang
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Xiaofei Gao
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Zhen Ge
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yue Gu
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Peng Ye
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yuelin Chao
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Linlin Zhu
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Xiaobo Li
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Shaoliang Chen
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
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25
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Reid DJ, Diesing JM, Miller MA, Perry SM, Wales JA, Montfort WR, Marty MT. MetaUniDec: High-Throughput Deconvolution of Native Mass Spectra. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:118-127. [PMID: 29667162 PMCID: PMC6192864 DOI: 10.1007/s13361-018-1951-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 02/23/2018] [Accepted: 03/10/2018] [Indexed: 05/11/2023]
Abstract
The expansion of native mass spectrometry (MS) methods for both academic and industrial applications has created a substantial need for analysis of large native MS datasets. Existing software tools are poorly suited for high-throughput deconvolution of native electrospray mass spectra from intact proteins and protein complexes. The UniDec Bayesian deconvolution algorithm is uniquely well suited for high-throughput analysis due to its speed and robustness but was previously tailored towards individual spectra. Here, we optimized UniDec for deconvolution, analysis, and visualization of large data sets. This new module, MetaUniDec, centers around a hierarchical data format 5 (HDF5) format for storing datasets that significantly improves speed, portability, and file size. It also includes code optimizations to improve speed and a new graphical user interface for visualization, interaction, and analysis of data. To demonstrate the utility of MetaUniDec, we applied the software to analyze automated collision voltage ramps with a small bacterial heme protein and large lipoprotein nanodiscs. Upon increasing collisional activation, bacterial heme-nitric oxide/oxygen binding (H-NOX) protein shows a discrete loss of bound heme, and nanodiscs show a continuous loss of lipids and charge. By using MetaUniDec to track changes in peak area or mass as a function of collision voltage, we explore the energetic profile of collisional activation in an ultra-high mass range Orbitrap mass spectrometer. Graphical abstract ᅟ.
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Affiliation(s)
- Deseree J Reid
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ, 85721, USA
| | - Jessica M Diesing
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ, 85721, USA
| | - Matthew A Miller
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ, 85721, USA
| | - Scott M Perry
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ, 85721, USA
| | - Jessica A Wales
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ, 85721, USA
| | - William R Montfort
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ, 85721, USA
| | - Michael T Marty
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ, 85721, USA.
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26
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Abstract
NMR spectroscopy has proven to be a key method for studying intrinsically disordered proteins (IDPs). Nonetheless, traditional NMR methods developed for solving structures of ordered protein complexes are insufficient for the full characterization of dynamic IDP complexes, where the energy landscape is broader and more rugged. Furthermore, due to their high sensitivity to environmental changes, NMR studies of IDP complexes must be conducted with extra care and the observed NMR parameters thoroughly evaluated to enable disentanglement of binding events from ensemble distribution changes. In this chapter, written for the non-NMR expert, we start out by outlining sample preparation for IDP complexes, guide through the recording and evaluation of diagnostic 1H,15N-HSQC spectra, and delineate more sophisticated NMR strategies to follow for the particular type of complex. The most relevant experiments are then described in terms of aims, needs, pitfalls, analysis, and expected outcomes, with references to recent examples.
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27
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Guan X, Hasan MN, Begum G, Kohanbash G, Carney KE, Pigott VM, Persson AI, Castro MG, Jia W, Sun D. Blockade of Na/H exchanger stimulates glioma tumor immunogenicity and enhances combinatorial TMZ and anti-PD-1 therapy. Cell Death Dis 2018; 9:1010. [PMID: 30262908 PMCID: PMC6160445 DOI: 10.1038/s41419-018-1062-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/21/2018] [Accepted: 09/10/2018] [Indexed: 12/28/2022]
Abstract
The weak immunogenicity of gliomas presents a barrier for effective immunotherapy. Na/H exchanger isoform 1 (NHE1) maintains alkaline intracellular pH (pHi) of glioma cells and acidic microenvironment. In addition, NHE1 is expressed in tumor-associated microglia and tumor-associated macrophages (TAMs) and involved in protumoral communications between glioma and TAMs. Therefore, we hypothesize that NHE1 plays a role in developing tumor resistance and immunosuppressive tumor microenvironment. In this study, we investigated the efficacy of pharmacological inhibition of NHE1 on combinatorial therapies. Here we show that temozolomide (TMZ) treatment stimulates NHE1 protein expression in two intracranial syngeneic mouse glioma models (SB28, GL26). Pharmacological inhibition of NHE1 potentiated the cytotoxic effects of TMZ, leading to reduced tumor growth and increased median survival of mice. Blockade of NHE1 stimulated proinflammatory activation of TAM and increased cytotoxic T cell infiltration into tumors. Combining TMZ, anti-PD-1 antibody treatment with NHE1 blockade significantly prolonged the median survival in the mouse glioma model. These results demonstrate that pharmacological inhibition of NHE1 protein presents a new strategy for potentiating TMZ-induced cytotoxicity and increasing tumor immunogenicity for immunotherapy to improve glioma therapy.
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Affiliation(s)
- Xiudong Guan
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
- Chinese National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Md Nabiul Hasan
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gary Kohanbash
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Karen E Carney
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Victoria M Pigott
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Anders I Persson
- Department of Neurology, University of California, San Francisco, CA, USA
- Department of Neurological Surgery, University of California, San Francisco, CA, USA
| | - Maria G Castro
- Department of Neurological Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Wang Jia
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
- Chinese National Clinical Research Center for Neurological Diseases, Beijing, China.
- Beijing Neurosurgical Institute, Beijing, China.
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
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28
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Flinck M, Kramer SH, Pedersen SF. Roles of pH in control of cell proliferation. Acta Physiol (Oxf) 2018; 223:e13068. [PMID: 29575508 DOI: 10.1111/apha.13068] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/17/2018] [Accepted: 03/19/2018] [Indexed: 02/06/2023]
Abstract
Precise spatiotemporal regulation of intracellular pH (pHi ) is a prerequisite for normal cell function, and changes in pHi or pericellular pH (pHe ) exert important signalling functions. It is well established that proliferation of mammalian cells is dependent on a permissive pHi in the slightly alkaline range (7.0-7.2). It is also clear that mitogen signalling in nominal absence of HCO3- is associated with an intracellular alkalinization (~0.3 pH unit above steady-state pHi ), which is secondary to activation of Na+ /H+ exchange. However, it remains controversial whether this increase in pHi is part of the mitogenic signal cascade leading to cell cycle entry and progression, and whether it is relevant under physiological conditions. Furthermore, essentially all studies of pHi in mammalian cell proliferation have focused on the mitogen-induced G0-G1 transition, and the regulation and roles of pHi during the cell cycle remain poorly understood. The aim of this review is to summarize and critically discuss the possible roles of pHi and pHe in cell cycle progression. While the focus is on the mammalian cell cycle, important insights from studies in lower eukaryotes are also discussed. We summarize current evidence of links between cell cycle progression and pHi and discuss possible pHi - and pHe sensors and signalling pathways relevant to mammalian proliferation control. The possibility that changes in pHi during cell cycle progression may be an integral part of the checkpoint control machinery is explored. Finally, we discuss the relevance of links between pH and proliferation in the context of the perturbed pH homoeostasis and acidic microenvironment of solid tumours.
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Affiliation(s)
- M. Flinck
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
| | - S. H. Kramer
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
| | - S. F. Pedersen
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
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29
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Borgia A, Borgia MB, Bugge K, Kissling VM, Heidarsson PO, Fernandes CB, Sottini A, Soranno A, Buholzer KJ, Nettels D, Kragelund BB, Best RB, Schuler B. Extreme disorder in an ultrahigh-affinity protein complex. Nature 2018; 555:61-66. [PMID: 29466338 DOI: 10.1038/nature25762] [Citation(s) in RCA: 441] [Impact Index Per Article: 73.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 01/17/2018] [Indexed: 12/23/2022]
Abstract
Molecular communication in biology is mediated by protein interactions. According to the current paradigm, the specificity and affinity required for these interactions are encoded in the precise complementarity of binding interfaces. Even proteins that are disordered under physiological conditions or that contain large unstructured regions commonly interact with well-structured binding sites on other biomolecules. Here we demonstrate the existence of an unexpected interaction mechanism: the two intrinsically disordered human proteins histone H1 and its nuclear chaperone prothymosin-α associate in a complex with picomolar affinity, but fully retain their structural disorder, long-range flexibility and highly dynamic character. On the basis of closely integrated experiments and molecular simulations, we show that the interaction can be explained by the large opposite net charge of the two proteins, without requiring defined binding sites or interactions between specific individual residues. Proteome-wide sequence analysis suggests that this interaction mechanism may be abundant in eukaryotes.
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Affiliation(s)
- Alessandro Borgia
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Madeleine B Borgia
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Katrine Bugge
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science and Integrative Structural Biology at University of Copenhagen (ISBUC), Department of Biology, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Vera M Kissling
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Pétur O Heidarsson
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Catarina B Fernandes
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science and Integrative Structural Biology at University of Copenhagen (ISBUC), Department of Biology, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Andrea Sottini
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Andrea Soranno
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland.,Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Karin J Buholzer
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science and Integrative Structural Biology at University of Copenhagen (ISBUC), Department of Biology, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland.,Department of Physics, University of Zurich, 8057 Zurich, Switzerland
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30
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Andersen AP, Samsøe-Petersen J, Oernbo EK, Boedtkjer E, Moreira JMA, Kveiborg M, Pedersen SF. The net acid extruders NHE1, NBCn1 and MCT4 promote mammary tumor growth through distinct but overlapping mechanisms. Int J Cancer 2018; 142:2529-2542. [PMID: 29363134 DOI: 10.1002/ijc.31276] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/16/2017] [Accepted: 01/17/2018] [Indexed: 01/01/2023]
Abstract
High metabolic and proliferative rates in cancer cells lead to production of large amounts of H+ and CO2 , and as a result, net acid extruding transporters are essential for the function and survival of cancer cells. We assessed protein expression of the Na+ /H+ exchanger NHE1, the Na+ - HCO3- cotransporter NBCn1, and the lactate-H+ cotransporters MCT1 and -4 by immunohistochemical analysis of a large cohort of breast cancer samples. We found robust expression of these transporters in 20, 10, 4 and 11% of samples, respectively. NHE1 and NBCn1 expression both correlated positively with progesterone receptor status, NHE1 correlated negatively and NBCn1 positively with HER2 status, whereas MCT4 expression correlated with lymph node status. Stable shRNA-mediated knockdown (KD) of either NHE1 or NBCn1 in the MDA-MB-231 triple-negative breast cancer (TNBC) cell line significantly reduced steady-state intracellular pH (pHi ) and capacity for pHi recovery after an acid load. Importantly, KD of any of the three transporters reduced in vivo primary tumor growth of MDA-MB-231 xenografts. However, whereas KD of NBCn1 or MCT4 increased tumor-free survival and decreased in vitro proliferation rate and colony growth in soft agar, KD of NHE1 did not have these effects. Moreover, only MCT4 KD reduced Akt kinase activity, PARP and CD147 expression and cell motility. This work reveals that different types of net acid extruding transporters, NHE1, NBCn1 and MCT4, are frequently expressed in patient mammary tumor tissue and demonstrates for the first time that they promote growth of TNBC human mammary tumors in vivo via distinct but overlapping mechanisms.
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Affiliation(s)
- Anne Poder Andersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Samsøe-Petersen
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Eva Kjer Oernbo
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - José M A Moreira
- Section for Molecular Disease Biology, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Kveiborg
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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31
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Kjaergaard M, Kragelund BB. Functions of intrinsic disorder in transmembrane proteins. Cell Mol Life Sci 2017; 74:3205-3224. [PMID: 28601983 PMCID: PMC11107515 DOI: 10.1007/s00018-017-2562-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022]
Abstract
Intrinsic disorder is common in integral membrane proteins, particularly in the intracellular domains. Despite this observation, these domains are not always recognized as being disordered. In this review, we will discuss the biological functions of intrinsically disordered regions of membrane proteins, and address why the flexibility afforded by disorder is mechanistically important. Intrinsically disordered regions are present in many common classes of membrane proteins including ion channels and transporters; G-protein coupled receptors (GPCRs), receptor tyrosine kinases and cytokine receptors. The functions of the disordered regions are many and varied. We will discuss selected examples including: (1) Organization of receptors, kinases, phosphatases and second messenger sources into signaling complexes. (2) Modulation of the membrane-embedded domain function by ball-and-chain like mechanisms. (3) Trafficking of membrane proteins. (4) Transient membrane associations. (5) Post-translational modifications most notably phosphorylation and (6) disorder-linked isoform dependent function. We finish the review by discussing the future challenges facing the membrane protein community regarding protein disorder.
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Affiliation(s)
- Magnus Kjaergaard
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
- The Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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32
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Hendus-Altenburger R, Lambrughi M, Terkelsen T, Pedersen SF, Papaleo E, Lindorff-Larsen K, Kragelund BB. A phosphorylation-motif for tuneable helix stabilisation in intrinsically disordered proteins - Lessons from the sodium proton exchanger 1 (NHE1). Cell Signal 2017; 37:40-51. [PMID: 28554535 DOI: 10.1016/j.cellsig.2017.05.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 11/26/2022]
Abstract
Intrinsically disordered proteins (IDPs) are involved in many pivotal cellular processes including phosphorylation and signalling. The structural and functional effects of phosphorylation of IDPs remain poorly understood and difficult to predict. Thus, a need exists to identify motifs that confer phosphorylation-dependent perturbation of the local preferences for forming e.g. helical structures as well as motifs that do not. The disordered distal tail of the Na+/H+ exchanger 1 (NHE1) is six-times phosphorylated (S693, S723, S726, S771, T779, S785) by the mitogen activated protein kinase 2 (MAPK1, ERK2). Using NMR spectroscopy, we found that two out of those six phosphorylation sites had a stabilizing effect on transient helices. One of these was further investigated by circular dichroism and NMR spectroscopy as well as by molecular dynamic simulations, which confirmed the stabilizing effect and resulted in the identification of a short linear motif for helix stabilisation: [S/T]-P-{3}-[R/K] where [S/T] is the phosphorylation-site. By analysing IDP and phosphorylation site databases we found that the motif is significantly enriched around known phosphorylation sites, supporting a potential wider-spread role in phosphorylation-mediated regulation of intrinsically disordered proteins. The identification of such motifs is important for understanding the molecular mechanism of cellular signalling, and is crucial for the development of predictors for the structural effect of phosphorylation; a tool of relevance for understanding disease-promoting mutations that for example interfere with signalling for instance through constitutive active and often cancer-promoting signalling.
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Affiliation(s)
- Ruth Hendus-Altenburger
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Matteo Lambrughi
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Strandboulevarden 49, 2100 Copenhagen, Denmark.
| | - Thilde Terkelsen
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Strandboulevarden 49, 2100 Copenhagen, Denmark.
| | - Stine F Pedersen
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark.
| | - Elena Papaleo
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Strandboulevarden 49, 2100 Copenhagen, Denmark.
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
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33
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Prasad H, Osei-Owusu J, Rao R. Functional analysis of Na +/H + exchanger 9 variants identified in patients with autism and epilepsy. ACTA ACUST UNITED AC 2017; 2017. [PMID: 28815171 PMCID: PMC5555647 DOI: 10.19185/matters.201704000009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Na+/H+ exchanger isoform 9, NHE9, finely tunes the pH within the endosomal lumen to regulate cargo trafficking and turnover. In patients with autism, genetic approaches have revealed deletions, truncations and missense mutations in the gene encoding NHE9 (SLC9A9). To help establish causality, functional evaluation is needed to distinguish pathogenic mutations from harmless polymorphisms. Here, we evaluated three previously uncharacterized NHE9 variants, P117T, D496N, and Q609K reported in patients with autism and epilepsy. We show that NHE9-DsRed localizes to recycling endosomes in HEK293 cells where it significantly alkalinizes luminal pH, and elevates accumulation of transferrin. All three NHE9 variants were expressed and localized to endosomal compartments, similar to wild-type NHE9. In contrast to previously characterized NHE9 variants, we observed no loss-of-function with respect to endosomal pH homeostasis and transferrin endocytosis. These findings suggest that the three NHE9 substitutions analyzed in our study are either benign polymorphisms or may have a cell-type specific or regulatory function not detected in our cell culture model. Our findings highlight the importance of combining the use of cellular studies of function with sequencing technologies that capture genomic variation in patients.
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Affiliation(s)
- Hari Prasad
- Department of Physiology, The Johns Hopkins University School of Medicine 725 N. Wolfe Street Baltimore MD 21205
| | - James Osei-Owusu
- Department of Physiology, The Johns Hopkins University School of Medicine 725 N. Wolfe Street Baltimore MD 21205
| | - Rajini Rao
- Department of Physiology, The Johns Hopkins University School of Medicine 725 N. Wolfe Street Baltimore MD 21205
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34
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Teilum K, Kunze MBA, Erlendsson S, Kragelund BB. (S)Pinning down protein interactions by NMR. Protein Sci 2017; 26:436-451. [PMID: 28019676 PMCID: PMC5326574 DOI: 10.1002/pro.3105] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 12/14/2016] [Accepted: 12/14/2016] [Indexed: 11/29/2022]
Abstract
Protein molecules are highly diverse communication platforms and their interaction repertoire stretches from atoms over small molecules such as sugars and lipids to macromolecules. An important route to understanding molecular communication is to quantitatively describe their interactions. These types of analyses determine the amounts and proportions of individual constituents that participate in a reaction as well as their rates of reactions and their thermodynamics. Although many different methods are available, there is currently no single method able to quantitatively capture and describe all types of protein reactions, which can span orders of magnitudes in affinities, reaction rates, and lifetimes of states. As the more versatile technique, solution NMR spectroscopy offers a remarkable catalogue of methods that can be successfully applied to the quantitative as well as qualitative descriptions of protein interactions. In this review we provide an easy-access approach to NMR for the non-NMR specialist and describe how and when solution state NMR spectroscopy is the method of choice for addressing protein ligand interaction. We describe very briefly the theoretical background and illustrate simple protein-ligand interactions as well as typical strategies for measuring binding constants using NMR spectroscopy. Finally, this review provides examples of caveats of the method as well as the options to improve the outcome of an NMR analysis of a protein interaction reaction.
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Affiliation(s)
- Kaare Teilum
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
| | - Micha Ben Achim Kunze
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
| | - Simon Erlendsson
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
| | - Birthe B. Kragelund
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
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35
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Amith SR, Fliegel L. Na +/H + exchanger-mediated hydrogen ion extrusion as a carcinogenic signal in triple-negative breast cancer etiopathogenesis and prospects for its inhibition in therapeutics. Semin Cancer Biol 2017; 43:35-41. [PMID: 28104391 DOI: 10.1016/j.semcancer.2017.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 12/17/2022]
Abstract
Breast cancer is the leading cause of cancer-related death in women in Europe and North America, and metastasis is the primary cause of fatality in patients with breast cancer. While some breast cancers are quite treatable, the triple-negative breast cancers are more metastatic and resistant to chemotherapy. There is clearly an urgent need for better treatments for this form of the disease. Breast cancer is characterized by genetically complex intra-tumour heterogeneity, particularly within the triple-negative clinical subtype. This complicates treatment options, so the development of specifically targeted chemotherapy for less treatable forms is critical. Dysregulation of pH homeostasis is a common factor in breast tumour cells. This occurs in concert with a metabolic switch to aerobic glycolysis that occurs at the onset of oncogenic transformation. The Na+/H+ exchanger isoform 1 (NHE1) is the major pH regulatory protein involved in the increased proton extrusion of breast cancer cells. Its increased activity results in intracellular alkalinisation and extracellular acidification that drives cancer progression. The acidification of the extracellular tumour microenvironment also contributes to the development of chemotherapy resistance. In this review, we outline the role of H+ as a carcinogenic signal and the role and regulation of NHE1 as a trigger for metastasis. We review recent evidence supporting the use of pharmacological inhibitors of NHE1 as a viable treatment option for triple-negative breast cancer.
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Affiliation(s)
- Schammim Ray Amith
- Biomedical Science, School of Life Sciences, Keele University, 103B Huxley Building, Keele, Staffordshire, ST5 5BG, United Kingdom.
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, 347 Medical Sciences Building, Edmonton, Alberta, T6G 2H7, Canada.
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36
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Stock C, Pedersen SF. Roles of pH and the Na +/H + exchanger NHE1 in cancer: From cell biology and animal models to an emerging translational perspective? Semin Cancer Biol 2016; 43:5-16. [PMID: 28007556 DOI: 10.1016/j.semcancer.2016.12.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/10/2016] [Indexed: 01/30/2023]
Abstract
Acidosis is characteristic of the solid tumor microenvironment. Tumor cells, because they are highly proliferative and anabolic, have greatly elevated metabolic acid production. To sustain a normal cytosolic pH homeostasis they therefore need to either extrude excess protons or to neutralize them by importing HCO3-, in both cases causing extracellular acidification in the poorly perfused tissue microenvironment. The Na+/H+ exchanger isoform 1 (NHE1) is a ubiquitously expressed acid-extruding membrane transport protein, and upregulation of its expression and/or activity is commonly correlated with tumor malignancy. The present review discusses current evidence on how altered pH homeostasis, and in particular NHE1, contributes to tumor cell motility, invasion, proliferation, and growth and facilitates evasion of chemotherapeutic cell death. We summarize data from in vitro studies, 2D-, 3D- and organotypic cell culture, animal models and human tissue, which collectively point to pH-regulation in general, and NHE1 in particular, as potential targets in combination chemotherapy. Finally, we discuss the possible pitfalls, side effects and cellular escape mechanisms that need to be considered in the process of translating the plethora of basic research data into a clinical setting.
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Affiliation(s)
- Christian Stock
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Stine Falsig Pedersen
- Department of Biology, Section for Cell Biology and Physiology, University of Copenhagen, Universitetsparken 13, 2100 Copenhagen, Denmark.
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37
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Amith SR, Vincent KM, Wilkinson JM, Postovit LM, Fliegel L. Defining the Na +/H + exchanger NHE1 interactome in triple-negative breast cancer cells. Cell Signal 2016; 29:69-77. [PMID: 27751915 DOI: 10.1016/j.cellsig.2016.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/04/2016] [Accepted: 10/13/2016] [Indexed: 12/30/2022]
Abstract
Mounting evidence supports a major role for the Na+/H+ exchanger NHE1 in cancer progression and metastasis. NHE1 is hyperactive at the onset of oncogenic transformation, resulting in intracellular alkalinization and extracellular microenvironmental acidification. These conditions promote invasion and facilitate metastasis. However, the signal pathways governing the regulation of exchanger activity are still unclear. This is especially important in the aggressively metastatic, triple-negative basal breast cancer subtype. We used affinity chromatography followed by mass spectrometry to identify novel and putative interaction partners of NHE1 in MDA-MB-231 triple-negative breast cancer cells. NHE1 associated with several types of proteins including cytoskeletal proteins and chaperones. We validated protein interactions by co-immunoprecipitation for: 14-3-3, AKT, α-enolase, CHP1, HSP70 and HSP90. Additionally, we used The Cancer Genome Atlas (TCGA) to study NHE1 gene expression in primary patient breast tumours versus adjacent normal tissue. NHE1 expression was elevated in breast tumour samples and, when broken down by breast cancer subtype, NHE1 gene expression was significantly lower in tumours of the basal subtype compared to luminal and HER2+ subtypes. Reverse phase protein array (RPPA) analysis showed that NHE1 expression positively correlated with p90RSK expression in basal, but not luminal, primary tumours. Other proteins were negatively correlated with NHE1 expression in basal breast cancer tumours. Taken together, our data provides the first insight into the signalling molecules that form the NHE1 interactome in triple-negative breast cancer cells. These results will focus our search for novel targeted therapies.
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Affiliation(s)
- Schammim Ray Amith
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - Krista Marie Vincent
- Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 3K7, Canada.
| | - Jodi Marie Wilkinson
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - Lynne Marie Postovit
- Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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38
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Pedraz-Cuesta E, Fredsted J, Jensen HH, Bornebusch A, Nejsum LN, Kragelund BB, Pedersen SF. Prolactin Signaling Stimulates Invasion via Na(+)/H(+) Exchanger NHE1 in T47D Human Breast Cancer Cells. Mol Endocrinol 2016; 30:693-708. [PMID: 27176613 DOI: 10.1210/me.2015-1299] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Prolactin (PRL) and its receptor (PRLR) are implicated in breast cancer invasiveness, although their exact roles remain controversial. The Na(+)/H(+) exchanger (NHE1) plays essential roles in cancer cell motility and invasiveness, but the PRLR and NHE1 have not previously been linked. Here we show that in T47D human breast cancer cells, which express high levels of PRLR and NHE1, exposure to PRL led to the activation of Janus kinase-2 (JAK2)/signal transducer and activator of transcription-5 (STAT5), Akt, and ERK1/2 signaling and the rapid formation of peripheral membrane ruffles, known to be associated with cell motility. NHE1 was present in small ruffles prior to PRL treatment and was further recruited to the larger, more dynamic ruffles induced by PRL exposure. In PRL-induced ruffles, NHE1 colocalized with activated Akt, ERK1/2, and the ERK effector p90Ribosomal S kinase (p90RSK), known regulators of NHE1 activity. Stimulation of T47D cells with PRL augmented p90RSK activation, Ser703-phosphorylation of NHE1, NHE1-dependent intracellular pH recovery, pericellular acidification, and NHE1-dependent invasiveness. NHE1 activity and localization to ruffles were attenuated by the inhibition of Akt and/or ERK1/2. In contrast, noncancerous MCF10A breast epithelial cells expressed NHE1 and PRLR at lower levels than T47D cells, and their stimulation with PRL induced neither NHE1 activation nor NHE1-dependent invasiveness. In conclusion, we show for the first time that PRLR activation stimulates breast cancer cell invasiveness via the activation of NHE1. We propose that PRL-induced NHE1 activation and the resulting NHE1-dependent invasiveness may contribute to the metastatic behavior of human breast cancer cells.
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Affiliation(s)
- Elena Pedraz-Cuesta
- Section for Cell Biology and Physiology (E.P.-C., J.F., A.B., S.F.P.), Department of Biology, and Structural Biology and NMR laboratory (B.B.K.), Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Department of Molecular Biology and Genetics (H.H.J.) and Department of Clinical Medicine and Interdisciplinary Nanoscience Center (H.H.J., L.N.N.), Aarhus University, DK-8000 Aarhus C, Denmark
| | - Jacob Fredsted
- Section for Cell Biology and Physiology (E.P.-C., J.F., A.B., S.F.P.), Department of Biology, and Structural Biology and NMR laboratory (B.B.K.), Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Department of Molecular Biology and Genetics (H.H.J.) and Department of Clinical Medicine and Interdisciplinary Nanoscience Center (H.H.J., L.N.N.), Aarhus University, DK-8000 Aarhus C, Denmark
| | - Helene H Jensen
- Section for Cell Biology and Physiology (E.P.-C., J.F., A.B., S.F.P.), Department of Biology, and Structural Biology and NMR laboratory (B.B.K.), Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Department of Molecular Biology and Genetics (H.H.J.) and Department of Clinical Medicine and Interdisciplinary Nanoscience Center (H.H.J., L.N.N.), Aarhus University, DK-8000 Aarhus C, Denmark
| | - Annika Bornebusch
- Section for Cell Biology and Physiology (E.P.-C., J.F., A.B., S.F.P.), Department of Biology, and Structural Biology and NMR laboratory (B.B.K.), Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Department of Molecular Biology and Genetics (H.H.J.) and Department of Clinical Medicine and Interdisciplinary Nanoscience Center (H.H.J., L.N.N.), Aarhus University, DK-8000 Aarhus C, Denmark
| | - Lene N Nejsum
- Section for Cell Biology and Physiology (E.P.-C., J.F., A.B., S.F.P.), Department of Biology, and Structural Biology and NMR laboratory (B.B.K.), Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Department of Molecular Biology and Genetics (H.H.J.) and Department of Clinical Medicine and Interdisciplinary Nanoscience Center (H.H.J., L.N.N.), Aarhus University, DK-8000 Aarhus C, Denmark
| | - Birthe B Kragelund
- Section for Cell Biology and Physiology (E.P.-C., J.F., A.B., S.F.P.), Department of Biology, and Structural Biology and NMR laboratory (B.B.K.), Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Department of Molecular Biology and Genetics (H.H.J.) and Department of Clinical Medicine and Interdisciplinary Nanoscience Center (H.H.J., L.N.N.), Aarhus University, DK-8000 Aarhus C, Denmark
| | - Stine F Pedersen
- Section for Cell Biology and Physiology (E.P.-C., J.F., A.B., S.F.P.), Department of Biology, and Structural Biology and NMR laboratory (B.B.K.), Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Department of Molecular Biology and Genetics (H.H.J.) and Department of Clinical Medicine and Interdisciplinary Nanoscience Center (H.H.J., L.N.N.), Aarhus University, DK-8000 Aarhus C, Denmark
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