1
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Singh PK, Kim S, Smith AW. HER4 is a high-affinity dimerization partner for all EGFR/HER/ErbB family proteins. Protein Sci 2024; 33:e5171. [PMID: 39276020 PMCID: PMC11401057 DOI: 10.1002/pro.5171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 08/21/2024] [Accepted: 08/26/2024] [Indexed: 09/16/2024]
Abstract
Human epidermal growth factor receptors (HER)-also known as EGFR or ErbB receptors-are a subfamily of receptor tyrosine kinases (RTKs) that play crucial roles in cell growth, division, and differentiation. HER4 (ErbB4) is the least studied member of this family, partly because its expression is lower in later stages of development. Recent work has suggested that HER4 can play a role in metastasis by regulating cell migration and invasiveness; however, unlike EGFR and HER2, the precise role that HER4 plays in tumorigenesis is still unresolved. Early work on HER family proteins suggested that there are direct interactions between the four members, but to date, there has been no single study of all four receptors in the same cell line with the same biophysical method. Here, we quantitatively measure the degree of association between HER4 and the other HER family proteins in live cells with a time-resolved fluorescence technique called pulsed interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). PIE-FCCS is sensitive to the oligomerization state of membrane proteins in live cells, while simultaneously measuring single-cell protein expression levels and diffusion coefficients. Our PIE-FCCS results demonstrate that HER4 interacts directly with all HER family members in the cell plasma membrane. The interaction between HER4 and other HER family members intensified in the presence of a HER4-specific ligand. Our work suggests that HER4 is a preferred dimerization partner for all HER family proteins, even in the absence of ligands.
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Affiliation(s)
- Pradeep Kumar Singh
- Department of Chemistry and BiochemistryTexas Tech UniversityLubbockTexasUSA
| | - Soyeon Kim
- Division of Cancer Biology, Department of MedicineMetroHealth Medical CenterClevelandOhioUSA
- Department of MedicineCase Western Reserve University School of MedicineClevelandOhioUSA
| | - Adam W. Smith
- Department of Chemistry and BiochemistryTexas Tech UniversityLubbockTexasUSA
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2
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Brown CM, Marrink SJ. Modeling membranes in situ. Curr Opin Struct Biol 2024; 87:102837. [PMID: 38744147 DOI: 10.1016/j.sbi.2024.102837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/26/2024] [Accepted: 04/23/2024] [Indexed: 05/16/2024]
Abstract
Molecular dynamics simulations of cellular membranes have come a long way-from simple model lipid bilayers to multicomponent systems capturing the crowded and complex nature of real cell membranes. In this opinionated minireview, we discuss the current challenge to simulate the dynamics of membranes in their native environment, in situ, with the prospect of reaching the level of whole cells and cell organelles using an integrative modeling framework.
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Affiliation(s)
- Chelsea M Brown
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands. https://twitter.com/chelseabrowncg
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands. s.j.marrinkrug.nl
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3
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Smith AW. Recent applications of fluorescence correlation spectroscopy in live cells. Curr Opin Chem Biol 2024; 81:102480. [PMID: 38905722 DOI: 10.1016/j.cbpa.2024.102480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 06/23/2024]
Abstract
As a time-domain analogue of fluorescence imaging, FCS offers valuable insights into molecular dynamics, interactions, and concentrations within living cells. The primary insight generated by FCS is molecular mobility and concentration, which makes it useful for investigating molecular-scale details without the need for enrichment or separation. A specific strength of FCS is the ability to probe protein-protein interactions in live cells and several recent applications in this area are summarized. FCS is also used to investigate plasma membrane protein organization, with many applications to cell surface receptors and the mechanisms of drug binding. Finally, FCS is undergoing continual methodological innovations, such as imaging FCS, SPIM-FCS PIE-FCCS, STED-FCS, three-color FCS, and massively parallel FCS, which extend the capabilities to investigate molecular dynamics at different spatial and temporal scales. These innovations enable detailed examinations of cellular processes, including cellular transport and the spatial organization of membrane proteins.
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Affiliation(s)
- Adam W Smith
- Texas Tech University, Department of Chemistry & Biochemistry, Lubbock, TX, USA.
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4
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Sarkar B, Ishii K, Tahara T. Pulsed-Interleaved-Excitation Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy. J Phys Chem B 2024; 128:4685-4695. [PMID: 38692581 PMCID: PMC11104349 DOI: 10.1021/acs.jpcb.4c01224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 04/13/2024] [Accepted: 04/17/2024] [Indexed: 05/03/2024]
Abstract
We report on pulsed-interleaved-excitation two-dimensional fluorescence lifetime correlation spectroscopy (PIE 2D FLCS) to study biomolecular structural dynamics with high sensitivity and high time resolution using Förster resonance energy transfer (FRET). PIE 2D FLCS is an extension of 2D FLCS, which is a unique single-molecule fluorescence method that uses fluorescence lifetime information to distinguish different fluorescence species in equilibrium and resolves their interconversion dynamics with a submicrosecond time resolution. Because 2D FLCS has used only a single-color excitation so far, it was difficult to distinguish a very low-FRET (or zero-FRET) species from only donor-labeled species. We overcome this difficulty by implementing the PIE scheme (i.e., alternate excitation of the donor and acceptor dyes using two temporally interleaved excitations with different colors) to 2D FLCS, realizing two-color excitation and two-color fluorescence detection in 2D FLCS. After proof-of-principle PIE 2D FLCS analysis on the photon data synthesized with Monte Carlo simulation, we apply PIE 2D FLCS to a DNA-hairpin sample and show that this method readily distinguishes four fluorescent species, i.e., high-FRET, low-FRET, and two single-dye-labeled species. In addition, we show that PIE 2D FLCS can also quantitatively evaluate the contributions of the donor-acceptor spectral crosstalk, which often appears as artifacts in FRET studies and degrades the information obtained.
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Affiliation(s)
- Bidyut Sarkar
- Molecular
Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Kunihiko Ishii
- Molecular
Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
- Ultrafast
Spectroscopy Research Team, RIKEN Center
for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
| | - Tahei Tahara
- Molecular
Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
- Ultrafast
Spectroscopy Research Team, RIKEN Center
for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
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5
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Singh PK, Rybak JA, Schuck RJ, Barrera FN, Smith AW. Phosphatidylinositol (4,5)-bisphosphate drives the formation of EGFR and EphA2 complexes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592400. [PMID: 38746348 PMCID: PMC11092790 DOI: 10.1101/2024.05.03.592400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Receptor tyrosine kinases (RTKs) regulate many cellular functions and are important targets in pharmaceutical development, particularly in cancer treatment. EGFR and EphA2 are two key RTKs that are associated with oncogenic phenotypes. Several studies have reported functional interplay between these receptors, but the mechanism of interaction is still unresolved. Here we utilize a time-resolved fluorescence spectroscopy called PIE-FCCS to resolve EGFR and EphA2 interactions in live cells. We tested the role of ligands and found that EGF, but not ephrin A1 (EA1), stimulated hetero-multimerization between the receptors. To determine the effect of anionic lipids, we targeted phospholipase C (PLC) activity to alter the abundance of phosphatidylinositol (4,5)-bisphosphate (PIP 2 ). We found that higher PIP 2 levels increased homo-multimerization of both EGFR and EphA2, as well as hetero-multimerization. This study provides a direct characterization of EGFR and EphA2 interactions in live cells and shows that PIP 2 can have a substantial effect on the spatial organization of RTKs.
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6
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Shimizu K, Sakaguchi M, Yamaguchi S, Otosu T. Peripheral adsorption of polylysine on one leaflet of a lipid bilayer reduces the lipid diffusion of both leaflets. Phys Chem Chem Phys 2024; 26:8873-8878. [PMID: 38426343 DOI: 10.1039/d3cp04882a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Understanding polycation-lipid interaction is essential not only in molecular biology but also in the biomedical industry and pharmacology. However, the effect of the polycation-lipid interaction on the molecular properties of lipids in biomembranes remains elusive. Here, two fluorescence correlation spectroscopies (FCSs), pulse-interleaved excitation (PIE) FCS and lifetime-based FCS, were performed to elucidate the change in the lipid diffusion of a model biomembrane induced by polylysine (PLL) adsorption. The results of PIE-FCS showed that the diffusions of both anionic and zwitterionic lipids become slower in the presence of PLL but the mobility of the anionic lipids is much reduced, suggesting the preferential interaction between the PLL and the anionic lipids due to the electrostatic attraction. Furthermore, leaflet-specific lipid diffusion analysis by lifetime-based FCS clearly showed that PLL adsorption on one leaflet of the membrane reduces the lipid diffusion of both leaflets in the same manner. This clearly indicates that the interleaflet coupling is strong in the presence of PLL.
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Affiliation(s)
- Kosei Shimizu
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
| | - Miyuki Sakaguchi
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
| | - Shoichi Yamaguchi
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
| | - Takuhiro Otosu
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
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7
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Kiani YS, Jabeen I. Challenges of Protein-Protein Docking of the Membrane Proteins. Methods Mol Biol 2024; 2780:203-255. [PMID: 38987471 DOI: 10.1007/978-1-0716-3985-6_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
Despite the recent advances in the determination of high-resolution membrane protein (MP) structures, the structural and functional characterization of MPs remains extremely challenging, mainly due to the hydrophobic nature, low abundance, poor expression, purification, and crystallization difficulties associated with MPs. Whereby the major challenges/hurdles for MP structure determination are associated with the expression, purification, and crystallization procedures. Although there have been significant advances in the experimental determination of MP structures, only a limited number of MP structures (approximately less than 1% of all) are available in the Protein Data Bank (PDB). Therefore, the structures of a large number of MPs still remain unresolved, which leads to the availability of widely unplumbed structural and functional information related to MPs. As a result, recent developments in the drug discovery realm and the significant biological contemplation have led to the development of several novel, low-cost, and time-efficient computational methods that overcome the limitations of experimental approaches, supplement experiments, and provide alternatives for the characterization of MPs. Whereby the fine tuning and optimizations of these computational approaches remains an ongoing endeavor.Computational methods offer a potential way for the elucidation of structural features and the augmentation of currently available MP information. However, the use of computational modeling can be extremely challenging for MPs mainly due to insufficient knowledge of (or gaps in) atomic structures of MPs. Despite the availability of numerous in silico methods for 3D structure determination the applicability of these methods to MPs remains relatively low since all methods are not well-suited or adequate for MPs. However, sophisticated methods for MP structure predictions are constantly being developed and updated to integrate the modifications required for MPs. Currently, different computational methods for (1) MP structure prediction, (2) stability analysis of MPs through molecular dynamics simulations, (3) modeling of MP complexes through docking, (4) prediction of interactions between MPs, and (5) MP interactions with its soluble partner are extensively used. Towards this end, MP docking is widely used. It is notable that the MP docking methods yet few in number might show greater potential in terms of filling the knowledge gap. In this chapter, MP docking methods and associated challenges have been reviewed to improve the applicability, accuracy, and the ability to model macromolecular complexes.
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Affiliation(s)
- Yusra Sajid Kiani
- School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Ishrat Jabeen
- School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan.
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8
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Shi X, Lingerak R, Herting CJ, Ge Y, Kim S, Toth P, Wang W, Brown BP, Meiler J, Sossey-Alaoui K, Buck M, Himanen J, Hambardzumyan D, Nikolov DB, Smith AW, Wang B. Time-resolved live-cell spectroscopy reveals EphA2 multimeric assembly. Science 2023; 382:1042-1050. [PMID: 37972196 PMCID: PMC11114627 DOI: 10.1126/science.adg5314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 11/01/2023] [Indexed: 11/19/2023]
Abstract
Ephrin type-A receptor 2 (EphA2) is a receptor tyrosine kinase that initiates both ligand-dependent tumor-suppressive and ligand-independent oncogenic signaling. We used time-resolved, live-cell fluorescence spectroscopy to show that the ligand-free EphA2 assembles into multimers driven by two types of intermolecular interactions in the ectodomain. The first type entails extended symmetric interactions required for ligand-induced receptor clustering and tumor-suppressive signaling that inhibits activity of the oncogenic extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) protein kinases and suppresses cell migration. The second type is an asymmetric interaction between the amino terminus and the membrane proximal domain of the neighboring receptors, which supports oncogenic signaling and promotes migration in vitro and tumor invasiveness in vivo. Our results identify the molecular interactions that drive the formation of the EphA2 multimeric signaling clusters and reveal the pivotal role of EphA2 assembly in dictating its opposing functions in oncogenesis.
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Affiliation(s)
- Xiaojun Shi
- Division of Cancer Biology, Department of Medicine, MetroHealth Medical Center, Cleveland, OH 44109, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Ryan Lingerak
- Division of Cancer Biology, Department of Medicine, MetroHealth Medical Center, Cleveland, OH 44109, USA
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Cameron J. Herting
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University, Atlanta, GA 30322, USA
| | - Yifan Ge
- Department of Molecular Biology, Massachusetts General Hospital and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Soyeon Kim
- Division of Cancer Biology, Department of Medicine, MetroHealth Medical Center, Cleveland, OH 44109, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Paul Toth
- Department of Chemistry, University of Akron, Akron, OH 44325, USA
| | - Wei Wang
- Division of Cancer Biology, Department of Medicine, MetroHealth Medical Center, Cleveland, OH 44109, USA
| | - Benjamin P. Brown
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Jens Meiler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Khalid Sossey-Alaoui
- Division of Cancer Biology, Department of Medicine, MetroHealth Medical Center, Cleveland, OH 44109, USA
| | - Matthias Buck
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Case Comprehensive Cancer Center, Cleveland, OH 44106, USA
| | - Juha Himanen
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Dolores Hambardzumyan
- Departments Oncological Sciences and Neurosurgery, Tisch Cancer Institute, Icahn School of Medicine, Mount Sinai, New York, NY 10029, USA
| | - Dimitar B. Nikolov
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Adam W. Smith
- Department of Chemistry, University of Akron, Akron, OH 44325, USA
| | - Bingcheng Wang
- Division of Cancer Biology, Department of Medicine, MetroHealth Medical Center, Cleveland, OH 44109, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Case Comprehensive Cancer Center, Cleveland, OH 44106, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
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9
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McKenzie DM, Wirth D, Pogorelov TV, Hristova K. Utility of FRET in studies of membrane protein oligomerization: The concept of the effective dissociation constant. Biophys J 2023; 122:4113-4120. [PMID: 37735871 PMCID: PMC10598290 DOI: 10.1016/j.bpj.2023.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/07/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023] Open
Abstract
The activity of many membrane receptors is controlled through their lateral association into dimers or higher-order oligomers. Although Förster resonance energy transfer (FRET) measurements have been used extensively to characterize the stability of receptor dimers, the utility of FRET in studies of larger oligomers has been limited. Here we introduce an effective equilibrium dissociation constant that can be extracted from FRET measurements for EphA2, a receptor tyrosine kinase (RTK) known to form active oligomers of heterogeneous distributions in response to its ligand ephrinA1-Fc. The newly introduced effective equilibrium dissociation constant has a well-defined physical meaning and biological significance. It denotes the receptor concentration for which half of the receptors are monomeric and inactive, and the other half are associated into oligomers and are active, irrespective of the exact oligomer size. This work introduces a new dimension to the utility of FRET in studies of membrane receptor association and signaling in the plasma membrane.
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Affiliation(s)
- Daniel M McKenzie
- Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, Maryland
| | - Daniel Wirth
- Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, Maryland
| | - Taras V Pogorelov
- Department of Chemistry, Center for Biophysics and Quantitative Biology, School of Chemical Sciences, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, Maryland.
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10
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Gandhi SA, Sanders MA, Granneman JG, Kelly CV. Four-color fluorescence cross-correlation spectroscopy with one laser and one camera. BIOMEDICAL OPTICS EXPRESS 2023; 14:3812-3827. [PMID: 37497523 PMCID: PMC10368031 DOI: 10.1364/boe.486937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/14/2023] [Accepted: 04/18/2023] [Indexed: 07/28/2023]
Abstract
The diffusion and reorganization of phospholipids and membrane-associated proteins are fundamental for cellular function. Fluorescence cross-correlation spectroscopy (FCCS) measures diffusion and molecular interactions at nanomolar concentration in biological systems. We have developed an economical method to simultaneously monitor diffusion and complexation with the use of super-continuum laser and spectral deconvolution from a single detector. Customizable excitation wavelengths were chosen from the wide-band source and spectral fitting of the emitted light revealed the interactions for up to four chromatically overlapping fluorophores simultaneously. This method was applied to perform four-color FCCS that we demonstrated with polystyrene nanoparticles, lipid vesicles, and membrane-bound molecules. Up to four individually customizable excitation channels were selected from the broad-spectrum fiber laser to excite the diffusers within a diffraction-limited spot. The fluorescence emission passed through a cleanup filter and a dispersive prism prior to being collected by a sCMOS or EMCCD camera with up to 1.8 kHz frame rates. The emission intensity versus time of each fluorophore was extracted through a linear least-square fitting of each camera frame and temporally correlated via custom software. Auto- and cross-correlation functions enabled the measurement of the diffusion rates and binding partners. We have measured the induced aggregation of nanobeads and lipid vesicles in solution upon increasing the buffer salinity. Because of the adaptability of investigating four fluorophores simultaneously with a cost-effective method, this technique will have wide application for examining macromolecular complex formation in model and living systems.
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Affiliation(s)
- Sonali A. Gandhi
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA
| | - Matthew A. Sanders
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, MI 40201, USA
| | - James G. Granneman
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, MI 40201, USA
- Center for Integrative Metabolic and Endocrine Research, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Christopher V. Kelly
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA
- Center for Integrative Metabolic and Endocrine Research, School of Medicine, Wayne State University, Detroit, MI 48201, USA
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11
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Rybak JA, Sahoo AR, Kim S, Pyron RJ, Pitts SB, Guleryuz S, Smith AW, Buck M, Barrera FN. Allosteric inhibition of the epidermal growth factor receptor through disruption of transmembrane interactions. J Biol Chem 2023; 299:104914. [PMID: 37315787 PMCID: PMC10362150 DOI: 10.1016/j.jbc.2023.104914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/16/2023] Open
Abstract
The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase (RTK) commonly targeted for inhibition by anticancer therapeutics. Current therapeutics target EGFR's kinase domain or extracellular region. However, these types of inhibitors are not specific for tumors over healthy tissue and therefore cause undesirable side effects. Our lab has recently developed a new strategy to regulate RTK activity by designing a peptide that specifically binds to the transmembrane (TM) region of the RTK to allosterically modify kinase activity. These peptides are acidity-responsive, allowing them to preferentially target acidic environments like tumors. We have applied this strategy to EGFR and created the PET1 peptide. We observed that PET1 behaves as a pH-responsive peptide that modulates the configuration of the EGFR TM through a direct interaction. Our data indicated that PET1 inhibits EGFR-mediated cell migration. Finally, we investigated the mechanism of inhibition through molecular dynamics simulations, which showed that PET1 sits between the two EGFR TM helices; this molecular mechanism was additionally supported by AlphaFold-Multimer predictions. We propose that the PET1-induced disruption of native TM interactions disturbs the conformation of the kinase domain in such a way that it inhibits EGFR's ability to send migratory cell signals. This study is a proof-of-concept that acidity-responsive membrane peptide ligands can be generally applied to RTKs. In addition, PET1 constitutes a viable approach to therapeutically target the TM of EGFR.
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Affiliation(s)
- Jennifer A Rybak
- Department of Genome Sciences and Technology, University of Tennessee, Knoxville, Tennessee, USA
| | - Amita R Sahoo
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, Ohio, USA
| | - Soyeon Kim
- Department of Chemistry, University of Akron, Akron, Ohio, USA
| | - Robert J Pyron
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Savannah B Pitts
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Saffet Guleryuz
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA
| | - Adam W Smith
- Department of Chemistry, University of Akron, Akron, Ohio, USA; Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Matthias Buck
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, Ohio, USA
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA.
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12
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Kirsch ZJ, Blake JM, Huynh U, Agrohia DK, Tremblay CY, Graban EM, Vaughan RC, Vachet RW. Membrane Protein Binding Interactions Studied in Live Cells via Diethylpyrocarbonate Covalent Labeling Mass Spectrometry. Anal Chem 2023; 95:7178-7185. [PMID: 37102678 PMCID: PMC10350911 DOI: 10.1021/acs.analchem.2c05616] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Membrane proteins are vital in the human proteome for their cellular functions and make up a majority of drug targets in the U.S. However, characterizing their higher-order structures and interactions remains challenging. Most often membrane proteins are studied in artificial membranes, but such artificial systems do not fully account for the diversity of components present in cell membranes. In this study, we demonstrate that diethylpyrocarbonate (DEPC) covalent labeling mass spectrometry can provide binding site information for membrane proteins in living cells using membrane-bound tumor necrosis factor α (mTNFα) as a model system. Using three therapeutic monoclonal antibodies that bind TNFα, our results show that residues that are buried in the epitope upon antibody binding generally decrease in DEPC labeling extent. Additionally, serine, threonine, and tyrosine residues on the periphery of the epitope increase in labeling upon antibody binding because of a more hydrophobic microenvironment that is created. We also observe changes in labeling away from the epitope, indicating changes to the packing of the mTNFα homotrimer, compaction of the mTNFα trimer against the cell membrane, and/or previously uncharacterized allosteric changes upon antibody binding. Overall, DEPC-based covalent labeling mass spectrometry offers an effective means of characterizing structure and interactions of membrane proteins in living cells.
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Affiliation(s)
- Zachary J. Kirsch
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Jeanna M. Blake
- QuarryBio, Collins Building, 2051 East Paul Dirac Dr., Tallahassee, FL 32310
| | - Uyen Huynh
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Dheeraj K. Agrohia
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Catherine Y. Tremblay
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Eric M. Graban
- QuarryBio, Collins Building, 2051 East Paul Dirac Dr., Tallahassee, FL 32310
| | - Robert C. Vaughan
- QuarryBio, Collins Building, 2051 East Paul Dirac Dr., Tallahassee, FL 32310
| | - Richard W. Vachet
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
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13
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Yang HC, Li W, Sun J, Gross ML. Advances in Mass Spectrometry on Membrane Proteins. MEMBRANES 2023; 13:457. [PMID: 37233518 PMCID: PMC10220746 DOI: 10.3390/membranes13050457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/15/2023] [Accepted: 04/21/2023] [Indexed: 05/27/2023]
Abstract
Understanding the higher-order structure of membrane proteins (MPs), which are vital for numerous biological processes, is crucial for comprehending their function. Although several biophysical approaches have been used to study the structure of MPs, limitations exist owing to the proteins' dynamic nature and heterogeneity. Mass spectrometry (MS) is emerging as a powerful tool for investigating membrane protein structure and dynamics. Studying MPs using MS, however, must meet several challenges including the lack of stability and solubility of MPs, the complexity of the protein-membrane system, and the difficulty of digestion and detection. To meet these challenges, recent advances in MS have engendered opportunities in resolving the dynamics and structures of MP. This article reviews achievements over the past few years that enable the study of MPs by MS. We first introduce recent advances in hydrogen deuterium exchange and native mass spectrometry for MPs and then focus on those footprinting methods that report on protein structure.
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Affiliation(s)
- Hsin-Chieh Yang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA;
| | - Jie Sun
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
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14
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Gandhi SA, Sanders MA, Granneman JG, Kelly CV. Four-color fluorescence cross-correlation spectroscopy with one laser and one camera. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526256. [PMID: 36778294 PMCID: PMC9915509 DOI: 10.1101/2023.01.30.526256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The diffusion and reorganization of phospholipids and membrane-associated proteins are fundamental for cellular function. Fluorescence cross-correlation spectroscopy (FCCS) measures the diffusion and molecular interactions at nanomolar concentration in biological systems. We have developed a novel, economical method to simultaneously monitor diffusion and oligomerization with the use of super-continuum laser and spectral deconvolution from a single detector. Customizable excitation wavelengths were chosen from the wide-band source and spectral fitting of the emitted light revealed the interactions for up to four spectrally overlapping fluorophores simultaneously. This method was applied to perform four-color FCCS, as demonstrated with polystyrene nanoparticles, lipid vesicles, and membrane-bound molecules. Up to four individually customizable excitation channels were selected from the broad-spectrum fiber laser to excite the diffusers within a diffraction-limited spot. The fluorescence emission passed through a cleanup filter and a dispersive prism prior to being collected by a sCMOS or EMCCD camera with up to 10 kHz frame rates. The emission intensity versus time of each fluorophore was extracted through a linear least-square fitting of each camera frame and temporally correlated via custom software. Auto- and cross-correlation functions enabled the measurement of the diffusion rates and binding partners. We have measured the induced aggregation of nanobeads and lipid vesicles in solution upon increasing the buffer salinity. Because of the adaptability of investigating four fluorophores simultaneously with a cost-effective method, this technique will have wide application for examining complex homo- and heterooligomerization in model and living systems.
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Affiliation(s)
- Sonali A. Gandhi
- Department of Physics and Astronomy, Wayne State University, Detroit, MI, USA, 48201
| | - Matthew A. Sanders
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, MI, USA, 40201
| | - James G. Granneman
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, MI, USA, 40201,Center for Integrative Metabolic and Endocrine Research, School of Medicine, Wayne State University, Detroit, MI, USA. 48201
| | - Christopher V. Kelly
- Department of Physics and Astronomy, Wayne State University, Detroit, MI, USA, 48201,Center for Integrative Metabolic and Endocrine Research, School of Medicine, Wayne State University, Detroit, MI, USA. 48201,Corresponding author:
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15
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Stevens JA, Grünewald F, van Tilburg PAM, König M, Gilbert BR, Brier TA, Thornburg ZR, Luthey-Schulten Z, Marrink SJ. Molecular dynamics simulation of an entire cell. Front Chem 2023; 11:1106495. [PMID: 36742032 PMCID: PMC9889929 DOI: 10.3389/fchem.2023.1106495] [Citation(s) in RCA: 35] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023] Open
Abstract
The ultimate microscope, directed at a cell, would reveal the dynamics of all the cell's components with atomic resolution. In contrast to their real-world counterparts, computational microscopes are currently on the brink of meeting this challenge. In this perspective, we show how an integrative approach can be employed to model an entire cell, the minimal cell, JCVI-syn3A, at full complexity. This step opens the way to interrogate the cell's spatio-temporal evolution with molecular dynamics simulations, an approach that can be extended to other cell types in the near future.
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Affiliation(s)
- Jan A. Stevens
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Fabian Grünewald
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - P. A. Marco van Tilburg
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Melanie König
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Benjamin R. Gilbert
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Champaign, IL, United States
| | - Troy A. Brier
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Champaign, IL, United States
| | - Zane R. Thornburg
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Champaign, IL, United States
| | - Zaida Luthey-Schulten
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Champaign, IL, United States
| | - Siewert J. Marrink
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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16
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Pan X, Tran T, Kirsch ZJ, Thompson LK, Vachet RW. Diethylpyrocarbonate-Based Covalent Labeling Mass Spectrometry of Protein Interactions in a Membrane Complex System. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:82-91. [PMID: 36475668 PMCID: PMC9812933 DOI: 10.1021/jasms.2c00262] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Membrane-associated proteins are important because they mediate interactions between a cell's external and internal environment and they are often targets of therapeutics. Characterizing their structures and binding interactions, however, is challenging because they typically must be solubilized using artificial membrane systems that can make measurements difficult. Mass spectrometry (MS) is emerging as a valuable tool for studying membrane-associated proteins, and covalent labeling MS has unique potential to provide higher order structure and binding information for these proteins in complicated membrane systems. Here, we demonstrate that diethylpyrocarbonate (DEPC) can be effectively used as a labeling reagent to characterize the binding interactions between a membrane-associated protein and its binding partners in an artificial membrane system. Using chemotaxis histidine kinase (CheA) as a model system, we demonstrate that DEPC-based covalent labeling MS can provide structural and binding information about the ternary complex of CheA with two other proteins that is consistent with structural models of this membrane-associated chemoreceptor system. Despite the moderate hydrophobicity of DEPC, we find that its reactivity with proteins is not substantially influenced by the presence of the artificial membranes. However, correct structural information for this multiprotein chemoreceptor system requires measurements of DEPC labeling at multiple reagent concentrations to enable an accurate comparison between CheA and its ternary complex in the chemoreceptor system. In addition to providing structural information that is consistent with the model of this complex system, the labeling data supplements structural information that is not sufficiently refined in the chemoreceptor model.
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Affiliation(s)
- Xiao Pan
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003
| | - Thomas Tran
- Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, MA 01003
| | - Zachary J. Kirsch
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003
| | - Lynmarie K. Thompson
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003
- Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, MA 01003
| | - Richard W. Vachet
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003
- Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, MA 01003
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17
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Zapata-Mercado E, Biener G, McKenzie DM, Wimley WC, Pasquale EB, Raicu V, Hristova K. The efficacy of receptor tyrosine kinase EphA2 autophosphorylation increases with EphA2 oligomer size. J Biol Chem 2022; 298:102370. [PMID: 35970390 PMCID: PMC9512837 DOI: 10.1016/j.jbc.2022.102370] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/30/2022] Open
Abstract
The receptor tyrosine kinase (RTK) EphA2 is expressed in epithelial and endothelial cells and controls the assembly of cell-cell junctions. EphA2 has also been implicated in many diseases, including cancer. Unlike most RTKs, which signal predominantly as dimers, EphA2 readily forms high-order oligomers upon ligand binding. Here, we investigated if a correlation exists between EphA2 signaling properties and the size of the EphA2 oligomers induced by multiple ligands, including the widely used ephrinA1-Fc ligand, the soluble monomeric m-ephrinA1, and novel engineered peptide ligands. We used fluorescence intensity fluctuation (FIF) spectrometry to characterize the EphA2 oligomer populations induced by the different ligands. Interestingly, we found that different monomeric and dimeric ligands induce EphA2 oligomers with widely different size distributions. Our comparison of FIF brightness distribution parameters and EphA2 signaling parameters reveals that the efficacy of EphA2 phosphorylation on tyrosine 588, an autophosphorylation response contributing to EphA2 activation, correlates with EphA2 mean oligomer size. However, we found that other characteristics, such as the efficacy of AKT inhibition and ligand bias coefficients, appear to be independent of EphA2 oligomer size. Taken together, this work highlights the utility of FIF in RTK signaling research and demonstrates a quantitative correlation between the architecture of EphA2 signaling complexes and signaling features.
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Affiliation(s)
- Elmer Zapata-Mercado
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Gabriel Biener
- Department of Physics, University of Wisconsin, Milwaukee, Wisconsin, USA
| | - Daniel M McKenzie
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - William C Wimley
- Tulane University School of Medicine, Department of Biochemistry and Molecular Biology, New Orleans, Louisiana, USA
| | - Elena B Pasquale
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
| | - Valerica Raicu
- Department of Physics, University of Wisconsin, Milwaukee, Wisconsin, USA; Department of Biological Sciences, University of Wisconsin, Milwaukee, Wisconsin, USA.
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA.
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18
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Pan X, Vachet RW. MEMBRANE PROTEIN STRUCTURES AND INTERACTIONS FROM COVALENT LABELING COUPLED WITH MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2022; 41:51-69. [PMID: 33145813 PMCID: PMC8093322 DOI: 10.1002/mas.21667] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 05/31/2023]
Abstract
Membrane proteins are incredibly important biomolecules because they mediate interactions between a cell's external and internal environment. Obtaining information about membrane protein structure and interactions is thus important for understanding these essential biomolecules. Compared with the analyses of water-soluble proteins, the structural analysis of membrane proteins is more challenging owing to their unique chemical properties and the presence of lipid components that are necessary to solubilize them. The combination of covalent labeling (CL) and mass spectrometry (MS) has recently been applied with great success to study membrane protein structure and interactions. These studies have demonstrated the many advantages that CL-MS methods have over other traditional biophysical techniques. In this review, we discuss both amino acid-specific and non-specific labeling approaches and the special considerations needed to address the unique challenges associated with interrogating membrane proteins. This review highlights the aspects of this approach that require special care to be applied correctly and provides a comprehensive review of the membrane protein systems that have been studied by CL-MS. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
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19
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The use of fluorescence correlation spectroscopy to characterise the molecular mobility of G protein-coupled receptors in membrane microdomains: an update. Biochem Soc Trans 2021; 49:1547-1554. [PMID: 34436556 DOI: 10.1042/bst20201001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 12/24/2022]
Abstract
It has become increasingly apparent that some G protein-coupled receptors (GPCRs) are not homogeneously expressed within the plasma membrane but may instead be organised within distinct signalling microdomains. These microdomains localise GPCRs in close proximity with other membrane proteins and intracellular signalling partners and could have profound implications for the spatial and temporal control of downstream signalling. In order to probe the molecular mechanisms that govern GPCR pharmacology within these domains, fluorescence techniques with effective single receptor sensitivity are required. Of these, fluorescence correlation spectroscopy (FCS) is a technique that meets this sensitivity threshold. This short review will provide an update of the recent uses of FCS based techniques in conjunction with GPCR subtype selective fluorescent ligands to characterise dynamic ligand-receptor interactions in whole cells and using purified GPCRs.
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20
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Otzen DE, Pedersen JN, Somavarapu AK, Clement A, Ji M, Petersen EH, Pedersen JS, Urban S, Schafer NP. Cys-labeling kinetics of membrane protein GlpG: a role for specific SDS binding and micelle changes? Biophys J 2021; 120:4115-4128. [PMID: 34370995 DOI: 10.1016/j.bpj.2021.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/20/2021] [Accepted: 08/03/2021] [Indexed: 01/01/2023] Open
Abstract
Empirically, α-helical membrane protein folding stability in surfactant micelles can be tuned by varying the mole fraction MFSDS of anionic (sodium dodecyl sulfate (SDS)) relative to nonionic (e.g., dodecyl maltoside (DDM)) surfactant, but we lack a satisfying physical explanation of this phenomenon. Cysteine labeling (CL) has thus far only been used to study the topology of membrane proteins, not their stability or folding behavior. Here, we use CL to investigate membrane protein folding in mixed DDM-SDS micelles. Labeling kinetics of the intramembrane protease GlpG are consistent with simple two-state unfolding-and-exchange rates for seven single-Cys GlpG variants over most of the explored MFSDS range, along with exchange from the native state at low MFSDS (which inconveniently precludes measurement of unfolding kinetics under native conditions). However, for two mutants, labeling rates decline with MFSDS at 0-0.2 MFSDS (i.e., native conditions). Thus, an increase in MFSDS seems to be a protective factor for these two positions, but not for the five others. We propose different scenarios to explain this and find the most plausible ones to involve preferential binding of SDS monomers to the site of CL (based on computational simulations) along with changes in size and shape of the mixed micelle with changing MFSDS (based on SAXS studies). These nonlinear impacts on protein stability highlights a multifaceted role for SDS in membrane protein denaturation, involving both direct interactions of monomeric SDS and changes in micelle size and shape along with the general effects on protein stability of changes in micelle composition.
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Affiliation(s)
- Daniel E Otzen
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus C, Denmark.
| | - Jannik Nedergaard Pedersen
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus C, Denmark
| | - Arun Kumar Somavarapu
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus C, Denmark
| | - Anders Clement
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus C, Denmark
| | - Ming Ji
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Emil Hartvig Petersen
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus C, Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus C, Denmark; Department of Chemistry, Aarhus University, Aarhus C, Denmark
| | - Sinisa Urban
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Nicholas P Schafer
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus C, Denmark
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21
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Christie SM, Hao J, Tracy E, Buck M, Yu JS, Smith AW. Interactions between semaphorins and plexin-neuropilin receptor complexes in the membranes of live cells. J Biol Chem 2021; 297:100965. [PMID: 34270956 PMCID: PMC8350011 DOI: 10.1016/j.jbc.2021.100965] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/30/2021] [Accepted: 07/12/2021] [Indexed: 11/27/2022] Open
Abstract
Signaling of semaphorin ligands via their plexin-neuropilin receptors is involved in tissue patterning in the developing embryo. These proteins play roles in cell migration and adhesion but are also important in disease etiology, including in cancer angiogenesis and metastasis. While some structures of the soluble domains of these receptors have been determined, the conformations of the full-length receptor complexes are just beginning to be elucidated, especially within the context of the plasma membrane. Pulsed-interleaved excitation fluorescence cross-correlation spectroscopy allows direct insight into the formation of protein-protein interactions in the membranes of live cells. Here, we investigated the homodimerization of neuropilin-1 (Nrp1), plexin A2, plexin A4, and plexin D1 using pulsed-interleaved excitation fluorescence cross-correlation spectroscopy. Consistent with previous studies, we found that Nrp1, plexin A2, and plexin A4 are present as dimers in the absence of exogenous ligand. Plexin D1, on the other hand, was monomeric under similar conditions, which had not been previously reported. We also found that plexin A2 and A4 assemble into a heteromeric complex. Stimulation with semaphorin 3A or semaphorin 3C neither disrupts nor enhances the dimerization of the receptors when expressed alone, suggesting that activation involves a conformational change rather than a shift in the monomer-dimer equilibrium. However, upon stimulation with semaphorin 3C, plexin D1 and Nrp1 form a heteromeric complex. This analysis of interactions provides a complementary approach to the existing structural and biochemical data that will aid in the development of new therapeutic strategies to target these receptors in cancer.
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Affiliation(s)
| | - Jing Hao
- Department of Cancer Biology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Erin Tracy
- Department of Chemistry, University of Akron, Akron, Ohio, USA
| | - Matthias Buck
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jennifer S Yu
- Department of Cancer Biology, Cleveland Clinic, Cleveland, Ohio, USA; Department of Radiation Oncology, Cleveland Clinic, Cleveland, Ohio, USA; Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, Ohio, USA
| | - Adam W Smith
- Department of Chemistry, University of Akron, Akron, Ohio, USA.
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22
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Li M, Xi N, Liu L. Peak force tapping atomic force microscopy for advancing cell and molecular biology. NANOSCALE 2021; 13:8358-8375. [PMID: 33913463 DOI: 10.1039/d1nr01303c] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The advent of atomic force microscopy (AFM) provides an exciting tool to detect molecular and cellular behaviors under aqueous conditions. AFM is able to not only visualize the surface topography of the specimens, but also can quantify the mechanical properties of the specimens by force spectroscopy assay. Nevertheless, integrating AFM topographic imaging with force spectroscopy assay has long been limited due to the low spatiotemporal resolution. In recent years, the appearance of a new AFM imaging mode called peak force tapping (PFT) has shattered this limit. PFT allows AFM to simultaneously acquire the topography and mechanical properties of biological samples with unprecedented spatiotemporal resolution. The practical applications of PFT in the field of life sciences in the past decade have demonstrated the excellent capabilities of PFT in characterizing the fine structures and mechanics of living biological systems in their native states, offering novel possibilities to reveal the underlying mechanisms guiding physiological/pathological activities. In this paper, the recent progress in cell and molecular biology that has been made with the utilization of PFT is summarized, and future perspectives for further progression and biomedical applications of PFT are provided.
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Affiliation(s)
- Mi Li
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China and Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China and University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Ning Xi
- Department of Industrial and Manufacturing Systems Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China and Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China and University of Chinese Academy of Sciences, Beijing 100049, China.
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23
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Rawat N, Singla-Pareek SL, Pareek A. Membrane dynamics during individual and combined abiotic stresses in plants and tools to study the same. PHYSIOLOGIA PLANTARUM 2021; 171:653-676. [PMID: 32949408 DOI: 10.1111/ppl.13217] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/25/2020] [Accepted: 09/13/2020] [Indexed: 05/15/2023]
Abstract
The plasma membrane (PM) is possibly the most diverse biological membrane of plant cells; it separates and guards the cell against its external environment. It has an extremely complex structure comprising a mosaic of lipids and proteins. The PM lipids are responsible for maintaining fluidity, permeability and integrity of the membrane and also influence the functioning of membrane proteins. However, the PM is the primary target of environmental stress, which affects its composition, conformation and properties, thereby disturbing the cellular homeostasis. Maintenance of integrity and fluidity of the PM is a prerequisite for ensuring the survival of plants during adverse environmental conditions. The ability of plants to remodel membrane lipid and protein composition plays a crucial role in adaptation towards varying abiotic environmental cues, including high or low temperature, drought, salinity and heavy metals stress. The dynamic changes in lipid composition affect the functioning of membrane transporters and ultimately regulate the physical properties of the membrane. Plant membrane-transport systems play a significant role in stress adaptation by cooperating with the membrane lipidome to maintain the membrane integrity under stressful conditions. The present review provides a holistic view of stress responses and adaptations in plants, especially the changes in the lipidome and proteome of PM under individual or combined abiotic stresses, which cause alterations in the activity of membrane transporters and modifies the fluidity of the PM. The tools to study the varying lipidome and proteome of the PM are also discussed.
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Affiliation(s)
- Nishtha Rawat
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sneh L Singla-Pareek
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi, 110067, India
| | - Ashwani Pareek
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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24
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Structure-function analysis of oncogenic EGFR Kinase Domain Duplication reveals insights into activation and a potential approach for therapeutic targeting. Nat Commun 2021; 12:1382. [PMID: 33654076 PMCID: PMC7925532 DOI: 10.1038/s41467-021-21613-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 01/28/2021] [Indexed: 02/07/2023] Open
Abstract
Mechanistic understanding of oncogenic variants facilitates the development and optimization of treatment strategies. We recently identified in-frame, tandem duplication of EGFR exons 18 - 25, which causes EGFR Kinase Domain Duplication (EGFR-KDD). Here, we characterize the prevalence of ERBB family KDDs across multiple human cancers and evaluate the functional biochemistry of EGFR-KDD as it relates to pathogenesis and potential therapeutic intervention. We provide computational and experimental evidence that EGFR-KDD functions by forming asymmetric EGF-independent intra-molecular and EGF-dependent inter-molecular dimers. Time-resolved fluorescence microscopy and co-immunoprecipitation reveals EGFR-KDD can form ligand-dependent inter-molecular homo- and hetero-dimers/multimers. Furthermore, we show that inhibition of EGFR-KDD activity is maximally achieved by blocking both intra- and inter-molecular dimerization. Collectively, our findings define a previously unrecognized model of EGFR dimerization, providing important insights for the understanding of EGFR activation mechanisms and informing personalized treatment of patients with tumors harboring EGFR-KDD. Finally, we establish ERBB KDDs as recurrent oncogenic events in multiple cancers. An EGFR mutant with kinase domain duplication (EGFR-KDD) was previously identified in an index patient, but the functional and therapeutic implications remain unclear. Here, the authors show that KDD occurs in other ErbB receptors in multiple cancers, and characterize the mechanism and inhibition of EGFR-KDD.
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25
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Sreenivasan VKA, Graus MS, Pillai RR, Yang Z, Goyette J, Gaus K. Influence of FRET and fluorescent protein maturation on the quantification of binding affinity with dual-channel fluorescence cross-correlation spectroscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:6137-6153. [PMID: 33282480 PMCID: PMC7687962 DOI: 10.1364/boe.401056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/08/2020] [Accepted: 09/08/2020] [Indexed: 06/12/2023]
Abstract
Protein-protein interactions at the plasma membrane mediate transmembrane signaling. Dual-channel fluorescence cross-correlation spectroscopy (dc-FCCS) is a method with which these interactions can be quantified in a cellular context. However, factors such as incomplete maturation of fluorescent proteins, spectral crosstalk, and fluorescence resonance energy transfer (FRET) affect quantification. Some of these can be corrected or accounted for during data analysis and/or interpretation. Here, we experimentally and analytically demonstrate that it is difficult to correct the error caused due to FRET when applying dc-FCCS to measure binding affinity or bound molecular concentrations. Additionally, the presence of dark fluorescent proteins due to incomplete maturation introduces further errors, which too cannot be corrected in the presence of FRET. Based on simulations, we find that modalities such as pulse-interleaved excitation FCCS do not eliminate FRET-induced errors. Finally, we demonstrate that the detrimental effect of FRET can be eliminated with careful experimental design when applying dc-FCCS to quantify protein-protein interactions at the plasma membrane of living cells.
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Affiliation(s)
- Varun K A Sreenivasan
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Matthew S Graus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Rashmi R Pillai
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Zhengmin Yang
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Jesse Goyette
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
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26
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Toksöz YS, Özyiğit İE, Bilen Ç, Arsu N, Karakuş E. Development of a fluorometric measurement system used in biological samples upon the determination of iron (II) metal ion. Prep Biochem Biotechnol 2020; 51:361-374. [PMID: 32935651 DOI: 10.1080/10826068.2020.1818257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
2-thioxanthone thioacetic acid (TXSCH2COOH, T), which has a fluorometric character, was used for new fluorometric system upon Fe(II) analysis in biological samples as the main target. T-BSA binary complex was firstly consisted with non-covalent interactions between T and BSA at the equilibrium concentration as 1.77 × 10-4.M. T-BSA binary complex emission was increased at the ratio of 24.40% due to stabilization property of BSA (pH:7), compared with T emission intensity. Fluorescence emission spectroscopy was used for the all measurements because of an economic, a sensitive and a practical method compared with other spectroscopic analysis. T-BSA-Fe(II) triple complex was also obtained by adding Fe(II) ion to T-BSA binary complex solution. Its characterization was performed to be investigated with optimum excitation wavelength, buffer concentration, pH and temperature as 297 nm, 10-3 M Tris HCl (10-2M NaCI), pH:7.2 at 25 °C, respectively. The results of Fe(II) analysis in serum showed a certain response in fluorometric T-BSA-Fe(II) triple complex measurement system as 50.42 ± 5.8 µg/dL. The analyses of our fluorometric triple complex system were compared with the reference electrochemiluminescence method and similar results were obtained. Fluorometric measurements of T-BSA-Fe(II) triple complex, its characterization and Fe(II) analysis in this system have not been investigated in literature gives originality to our study.
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Affiliation(s)
- Yavuz Selim Toksöz
- Department of Chemistry, Yildiz Technical University, Esenler, Istanbul, Turkey
| | | | - Çiğdem Bilen
- Department of Chemistry, Yildiz Technical University, Esenler, Istanbul, Turkey
| | - Nergis Arsu
- Department of Chemistry, Yildiz Technical University, Esenler, Istanbul, Turkey
| | - Emine Karakuş
- Department of Chemistry, Yildiz Technical University, Esenler, Istanbul, Turkey
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