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Kusumi A, Tsunoyama TA, Suzuki KGN, Fujiwara TK, Aladag A. Transient, nano-scale, liquid-like molecular assemblies coming of age. Curr Opin Cell Biol 2024; 89:102394. [PMID: 38963953 DOI: 10.1016/j.ceb.2024.102394] [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: 02/08/2024] [Revised: 06/02/2024] [Accepted: 06/06/2024] [Indexed: 07/06/2024]
Abstract
This review examines the dynamic mechanisms underlying cellular signaling, communication, and adhesion via transient, nano-scale, liquid-like molecular assemblies on the plasma membrane (PM). Traditional views posit that stable, solid-like molecular complexes perform these functions. However, advanced imaging reveals that many signaling and scaffolding proteins only briefly reside in these molecular complexes and that micron-scale protein assemblies on the PM, including cell adhesion structures and synapses, are likely made of archipelagoes of nanoliquid protein islands. Borrowing the concept of liquid-liquid phase separation to form micron-scale biocondensates, we propose that these nano-scale oligomers and assemblies are enabled by multiple weak but specific molecular interactions often involving intrinsically disordered regions. The signals from individual nanoliquid signaling complexes would occur as pulses. Single-molecule imaging emerges as a crucial technique for characterizing these transient nanoliquid assemblies on the PM, suggesting a shift toward a model where the fluidity of interactions underpins signal regulation and integration.
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Affiliation(s)
- Akihiro Kusumi
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan.
| | - Taka A Tsunoyama
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Kenichi G N Suzuki
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan; Institute for Glyco-core Research (iGCORE), Gifu University, Gifu 501-1193, Japan; National Cancer Center Research Institute, Tokyo 104-0045, Japan
| | - Takahiro K Fujiwara
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan
| | - Amine Aladag
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan
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2
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Pei R, Zhang J, Tan J, Luo Y, Ye S. Fermi Resonance of the N-D Stretching Mode Probing the Local Hydrogen-Bonding Environment in Proteins. J Phys Chem B 2024; 128:5658-5666. [PMID: 38836292 DOI: 10.1021/acs.jpcb.4c00390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Local H-bonding interactions are crucial for proteins to undergo various structural transitions and form different secondary structures. However, identifying slight distinctions in the local H-bonding of proteins is rather challenging. Here, we demonstrate that the Fermi resonance of the N-D stretching mode can provide an effective probe for the localized H-bonding environment of proteins both at the surface/interface and in the bulk. Using sum frequency generation vibrational spectroscopy and infrared spectroscopy, we established a correlation between the Fermi resonance of the N-D mode and protein secondary structures. The H-bond of N-D···C═O splits the N-D modes into two peaks (∼2410 and ∼2470 cm-1). The relative strength ratio (R) between the ∼2410 cm-1 peak and the ∼2470 cm-1 peak is very sensitive to H-bond strength and protein secondary structure. R is less than 1 for α-helical peptides, while R is greater than 1 for β-sheet peptides. For R < 2.5, both α-helical/loop structures and β-sheet structures exhibit almost identical Fermi coupling strengths (W = 28 cm-1). For R > 2.5, W decreases from 28 to 14 cm-1 and depends on the aggregation degree of the β-sheet oligomers or fibrils. The initial local H-bonding status impacts the misfolding dynamics of proteins at the lipid bilayer interface.
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Affiliation(s)
- Ruoqi Pei
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Jiahui Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Junjun Tan
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Yi Luo
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Shuji Ye
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
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3
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Zheng X, Ni Z, Pei Q, Wang M, Tan J, Bai S, Shi F, Ye S. Probing the Molecular Structure and Dynamics of Membrane-Bound Proteins during Misfolding Processes by Sum-Frequency Generation Vibrational Spectroscopy. Chempluschem 2024; 89:e202300684. [PMID: 38380553 DOI: 10.1002/cplu.202300684] [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: 11/23/2023] [Revised: 02/17/2024] [Accepted: 02/20/2024] [Indexed: 02/22/2024]
Abstract
Protein misfolding and amyloid formation are implicated in the protein dysfunction, but the underlying mechanism remains to be clarified due to the lack of effective tools for detecting the transient intermediates. Sum frequency generation vibrational spectroscopy (SFG-VS) has emerged as a powerful tool for identifying the structure and dynamics of proteins at the interfaces. In this review, we summarize recent SFG-VS studies on the structure and dynamics of membrane-bound proteins during misfolding processes. This paper first introduces the methods for determining the secondary structure of interfacial proteins: combining chiral and achiral spectra of amide A and amide I bands and combining amide I, amide II, and amide III spectral features. To demonstrate the ability of SFG-VS in investigating the interfacial protein misfolding and amyloid formation, studies on the interactions between different peptides/proteins (islet amyloid polypeptide, amyloid β, prion protein, fused in sarcoma protein, hen egg-white lysozyme, fusing fusion peptide, class I hydrophobin SC3 and class II hydrophobin HFBI) and surfaces such as lipid membranes are discussed. These molecular-level studies revealed that SFG-VS can provide a unique understanding of the mechanism of interfacial protein misfolding and amyloid formation in real time, in situ and without any exogenous labeling.
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Affiliation(s)
- Xiaoxuan Zheng
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Zijian Ni
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Quanbing Pei
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Mengmeng Wang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Junjun Tan
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Shiyu Bai
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Fangwen Shi
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Shuji Ye
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
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Byrne PO, Blade EG, Fisher BE, Ambrozak DR, Ramamohan AR, Graham BS, Loomis RJ, McLellan JS. Prefusion stabilization of the Hendra and Langya virus F proteins. J Virol 2024; 98:e0137223. [PMID: 38214525 PMCID: PMC10878279 DOI: 10.1128/jvi.01372-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/12/2023] [Indexed: 01/13/2024] Open
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are pathogenic paramyxoviruses that cause mild-to-severe disease in humans. As members of the Henipavirus genus, NiV and HeV use an attachment (G) glycoprotein and a class I fusion (F) glycoprotein to invade host cells. The F protein rearranges from a metastable prefusion form to an extended postfusion form to facilitate host cell entry. Prefusion NiV F elicits higher neutralizing antibody titers than postfusion NiV F, indicating that stabilization of prefusion F may aid vaccine development. A combination of amino acid substitutions (L104C/I114C, L172F, and S191P) is known to stabilize NiV F in its prefusion conformation, although the extent to which substitutions transfer to other henipavirus F proteins is not known. Here, we perform biophysical and structural studies to investigate the mechanism of prefusion stabilization in F proteins from three henipaviruses: NiV, HeV, and Langya virus (LayV). Three known stabilizing substitutions from NiV F transfer to HeV F and exert similar structural and functional effects. One engineered disulfide bond, located near the fusion peptide, is sufficient to stabilize the prefusion conformations of both HeV F and LayV F. Although LayV F shares low overall sequence identity with NiV F and HeV F, the region around the fusion peptide exhibits high sequence conservation across all henipaviruses. Our findings indicate that substitutions targeting this site of conformational change might be applicable to prefusion stabilization of other henipavirus F proteins and support the use of NiV as a prototypical pathogen for henipavirus vaccine antigen design.IMPORTANCEPathogenic henipaviruses such as Nipah virus (NiV) and Hendra virus (HeV) cause respiratory symptoms, with severe cases resulting in encephalitis, seizures, and coma. The work described here shows that the NiV and HeV fusion (F) proteins share common structural features with the F protein from an emerging henipavirus, Langya virus (LayV). Sequence alignment alone was sufficient to predict which known prefusion-stabilizing amino acid substitutions from NiV F would stabilize the prefusion conformations of HeV F and LayV F. This work also reveals an unexpected oligomeric interface shared by prefusion HeV F and NiV F. Together, these advances lay a foundation for future antigen design targeting henipavirus F proteins. In this way, Nipah virus can serve as a prototypical pathogen for the development of protective vaccines and monoclonal antibodies to prepare for potential henipavirus outbreaks.
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Affiliation(s)
- Patrick O. Byrne
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Elizabeth G. Blade
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Brian E. Fisher
- Viral Pathogenesis Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - David R. Ambrozak
- Immunology Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Ajit R. Ramamohan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | | | - Rebecca J. Loomis
- Viral Pathogenesis Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Jason S. McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
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Mudumbi KC, Burns EA, Schodt DJ, Petrova ZO, Kiyatkin A, Kim LW, Mangiacapre EM, Ortiz-Caraveo I, Rivera Ortiz H, Hu C, Ashtekar KD, Lidke KA, Lidke DS, Lemmon MA. Distinct interactions stabilize EGFR dimers and higher-order oligomers in cell membranes. Cell Rep 2024; 43:113603. [PMID: 38117650 PMCID: PMC10835193 DOI: 10.1016/j.celrep.2023.113603] [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: 06/23/2023] [Revised: 09/23/2023] [Accepted: 12/05/2023] [Indexed: 12/22/2023] Open
Abstract
The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase with important roles in many cellular processes as well as in cancer and other diseases. EGF binding promotes EGFR dimerization and autophosphorylation through interactions that are well understood structurally. How these dimers relate to higher-order EGFR oligomers seen in cell membranes, however, remains unclear. Here, we used single-particle tracking (SPT) and Förster resonance energy transfer imaging to examine how each domain of EGFR contributes to receptor oligomerization and the rate of receptor diffusion in the cell membrane. Although the extracellular region of EGFR is sufficient to drive receptor dimerization, we find that the EGF-induced EGFR slowdown seen by SPT requires higher-order oligomerization-mediated in part by the intracellular tyrosine kinase domain when it adopts an active conformation. Our data thus provide important insight into the interactions required for higher-order EGFR assemblies involved in EGF signaling.
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Affiliation(s)
- Krishna C Mudumbi
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA.
| | - Eric A Burns
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA; Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - David J Schodt
- Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87106, USA
| | - Zaritza O Petrova
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Anatoly Kiyatkin
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Lucy W Kim
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Emma M Mangiacapre
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Irais Ortiz-Caraveo
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA; Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Hector Rivera Ortiz
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Chun Hu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Kumar D Ashtekar
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Keith A Lidke
- Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87106, USA
| | - Diane S Lidke
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA; Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
| | - Mark A Lemmon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA.
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6
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Löwe M, Hänsch S, Hachani E, Schmitt L, Weidtkamp-Peters S, Kedrov A. Probing macromolecular crowding at the lipid membrane interface with genetically-encoded sensors. Protein Sci 2023; 32:e4797. [PMID: 37779215 PMCID: PMC10578116 DOI: 10.1002/pro.4797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/25/2023] [Accepted: 09/28/2023] [Indexed: 10/03/2023]
Abstract
Biochemical processes within the living cell occur in a highly crowded environment, where macromolecules, first of all proteins and nucleic acids, occupy up to 30% of the volume. The phenomenon of macromolecular crowding is not an exclusive feature of the cytoplasm and can be observed in the densely protein-packed, nonhomogeneous cellular membranes and at the membrane interfaces. Crowding affects diffusional and conformational dynamics of proteins within the lipid bilayer, alters kinetic and thermodynamic properties of biochemical reactions, and modulates the membrane organization. Despite its importance, the non-invasive quantification of the membrane crowding is not trivial. Here, we developed a genetically-encoded fluorescence-based sensor for probing the macromolecular crowding at the membrane interfaces. Two sensor variants, both composed of fluorescent proteins and a membrane anchor, but differing by flexible linker domains were characterized in vitro, and the procedures for the membrane reconstitution were established. Steric pressure induced by membrane-tethered synthetic and protein crowders altered the sensors' conformation, causing increase in the intramolecular Förster's resonance energy transfer. Notably, the effect of protein crowders only weakly correlated with their molecular weight, suggesting that other factors, such as shape and charge contribute to the crowding via the quinary interactions. Finally, measurements performed in inner membrane vesicles of Escherichia coli validated the crowding-dependent dynamics of the sensors in the physiologically relevant environment. The sensors offer broad opportunities to study interfacial crowding in a complex environment of native membranes, and thus add to the toolbox of methods for studying membrane dynamics and proteostasis.
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Affiliation(s)
- Maryna Löwe
- Synthetic Membrane Systems, Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sebastian Hänsch
- Center for Advanced imaging, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Eymen Hachani
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | | | - Alexej Kedrov
- Synthetic Membrane Systems, Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Situ AJ, Ulmer TS. Comparison of Integrin αIIbβ3 Transmembrane Association in Vesicles and Bicelles. Biochemistry 2023. [PMID: 37279176 DOI: 10.1021/acs.biochem.3c00177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Membrane proteins are commonly reconstituted in membrane mimics exhibiting discontinuous lipid bilayers. In contrast, the continuous membranes of cells are conceptually best represented by large unilamellar vesicles (LUVs). Here, we compared the thermodynamic stability of the integrin αIIbβ3 transmembrane (TM) complex between vesicles and bicelles to assess the consequence of this simplification. In LUVs, we further evaluated the strength of the αIIb(G972S)-β3(V700T) interaction that corresponds to the hydrogen bond interaction postulated for β2 integrins. An upper limit of 0.9 kcal/mol was estimated for superior TM complex stabilization in LUVs relative to bicelles. Compared to the αIIbβ3 TM complex stability in LUVs of 5.6 ± 0.2 kcal/mol, this limit is modest, indicating that bicelles performed well relative to LUVs. The implementation of β3(V700T) alleviated αIIb(G972S) destabilization by 0.4 ± 0.2 kcal/mol in confirmation of relatively weak hydrogen bonding. Interestingly, the hydrogen bond adjusts the TM complex stability to a level that is not achievable by merely varying the residue corresponding to αIIb(Gly972).
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Affiliation(s)
- Alan J Situ
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, United States
| | - Tobias S Ulmer
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, United States
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, United States
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8
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Mudumbi KC, Burns EA, Schodt DJ, Petrova ZO, Kiyatkin A, Kim LW, Mangiacapre EM, Ortiz-Caraveo I, Ortiz HR, Hu C, Ashtekar KD, Lidke KA, Lidke DS, Lemmon MA. Distinct interactions stabilize EGFR dimers and higher-order oligomers in cell membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536273. [PMID: 37090557 PMCID: PMC10120646 DOI: 10.1101/2023.04.10.536273] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase (RTK) with important roles in many cellular processes as well as cancer and other diseases. EGF binding promotes EGFR dimerization and autophosphorylation through interactions that are well understood structurally. However, it is not clear how these dimers relate to higher-order EGFR oligomers detected at the cell surface. We used single-particle tracking (SPT) and Förster resonance energy transfer (FRET) imaging to examine how each domain within EGFR contributes to receptor dimerization and the rate of its diffusion in the cell membrane. We show that the EGFR extracellular region is sufficient to drive receptor dimerization, but that the EGF-induced EGFR slow-down seen by SPT requires formation of higher order oligomers, mediated in part by the intracellular tyrosine kinase domain - but only when in its active conformation. Our data thus provide important insight into higher-order EGFR interactions required for EGF signaling.
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9
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Refinement of Singer-Nicolson fluid-mosaic model by microscopy imaging: Lipid rafts and actin-induced membrane compartmentalization. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184093. [PMID: 36423676 DOI: 10.1016/j.bbamem.2022.184093] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 11/22/2022]
Abstract
This year celebrates the 50th anniversary of the Singer-Nicolson fluid mosaic model for biological membranes. The next level of sophistication we have achieved for understanding plasma membrane (PM) structures, dynamics, and functions during these 50 years includes the PM interactions with cortical actin filaments and the partial demixing of membrane constituent molecules in the PM, particularly raft domains. Here, first, we summarize our current knowledge of these two structures and emphasize that they are interrelated. Second, we review the structure, molecular dynamics, and function of raft domains, with main focuses on raftophilic glycosylphosphatidylinositol-anchored proteins (GPI-APs) and their signal transduction mechanisms. We pay special attention to the results obtained by single-molecule imaging techniques and other advanced microscopy methods. We also clarify the limitations of present optical microscopy methods for visualizing raft domains, but emphasize that single-molecule imaging techniques can "detect" raft domains associated with molecules of interest in the PM.
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10
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Gandhi AK, Sun ZYJ, Huang YH, Kim WM, Yang C, Petsko GA, Beauchemin N, Blumberg RS. Structural analysis of human CEACAM1 oligomerization. Commun Biol 2022; 5:1042. [PMID: 36180783 PMCID: PMC9525683 DOI: 10.1038/s42003-022-03996-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 09/14/2022] [Indexed: 11/09/2022] Open
Abstract
The human (h) CEACAM1 GFCC’ face serves as a binding site for homophilic and heterophilic interactions with various microbial and host ligands. hCEACAM1 has also been observed to form oligomers and micro-clusters on the cell surface which are thought to regulate hCEACAM1-mediated signaling. However, the structural basis for hCEACAM1 higher-order oligomerization is currently unknown. To understand this, we report a hCEACAM1 IgV oligomer crystal structure which shows how GFCC’ face-mediated homodimerization enables highly flexible ABED face interactions to arise. Structural modeling and nuclear magnetic resonance (NMR) studies predict that such oligomerization is not impeded by the presence of carbohydrate side-chain modifications. In addition, using UV spectroscopy and NMR studies, we show that oligomerization is further facilitated by the presence of a conserved metal ion (Zn++ or Ni++) binding site on the G strand of the FG loop. Together these studies provide biophysical insights on how GFCC’ and ABED face interactions together with metal ion binding may facilitate hCEACAM1 oligomerization beyond dimerization. The crystal structure of human CEACAM1 IgV oligomer and structural analyses provide insight into higher-order oligomerization involving GFCC’ face-mediated homodimerization, flexible ABED interfaces, and dynamic metal-ion bridging.
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Affiliation(s)
- Amit K Gandhi
- Division of Gastroenterology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
| | - Zhen-Yu J Sun
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Yu-Hwa Huang
- Division of Gastroenterology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Walter M Kim
- Division of Gastroenterology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Chao Yang
- Division of Gastroenterology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Gregory A Petsko
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Nicole Beauchemin
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
| | - Richard S Blumberg
- Division of Gastroenterology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
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11
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Kratochvil HT, Newberry RW, Mensa B, Mravic M, DeGrado WF. Spiers Memorial Lecture: Analysis and de novo design of membrane-interactive peptides. Faraday Discuss 2021; 232:9-48. [PMID: 34693965 PMCID: PMC8979563 DOI: 10.1039/d1fd00061f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Membrane-peptide interactions play critical roles in many cellular and organismic functions, including protection from infection, remodeling of membranes, signaling, and ion transport. Peptides interact with membranes in a variety of ways: some associate with membrane surfaces in either intrinsically disordered conformations or well-defined secondary structures. Peptides with sufficient hydrophobicity can also insert vertically as transmembrane monomers, and many associate further into membrane-spanning helical bundles. Indeed, some peptides progress through each of these stages in the process of forming oligomeric bundles. In each case, the structure of the peptide and the membrane represent a delicate balance between peptide-membrane and peptide-peptide interactions. We will review this literature from the perspective of several biologically important systems, including antimicrobial peptides and their mimics, α-synuclein, receptor tyrosine kinases, and ion channels. We also discuss the use of de novo design to construct models to test our understanding of the underlying principles and to provide useful leads for pharmaceutical intervention of diseases.
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Affiliation(s)
- Huong T Kratochvil
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Robert W Newberry
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Bruk Mensa
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Marco Mravic
- Department of Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
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12
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Mechanism for the activation of the anaplastic lymphoma kinase receptor. Nature 2021; 600:153-157. [PMID: 34819673 PMCID: PMC8639797 DOI: 10.1038/s41586-021-04140-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 10/14/2021] [Indexed: 01/09/2023]
Abstract
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) that regulates important functions in the central nervous system1,2. The ALK gene is a hotspot for chromosomal translocation events that result in several fusion proteins that cause a variety of human malignancies3. Somatic and germline gain-of-function mutations in ALK were identified in paediatric neuroblastoma4-7. ALK is composed of an extracellular region (ECR), a single transmembrane helix and an intracellular tyrosine kinase domain8,9. ALK is activated by the binding of ALKAL1 and ALKAL2 ligands10-14 to its ECR, but the lack of structural information for the ALK-ECR or for ALKAL ligands has limited our understanding of ALK activation. Here we used cryo-electron microscopy, nuclear magnetic resonance and X-ray crystallography to determine the atomic details of human ALK dimerization and activation by ALKAL1 and ALKAL2. Our data reveal a mechanism of RTK activation that allows dimerization by either dimeric (ALKAL2) or monomeric (ALKAL1) ligands. This mechanism is underpinned by an unusual architecture of the receptor-ligand complex. The ALK-ECR undergoes a pronounced ligand-induced rearrangement and adopts an orientation parallel to the membrane surface. This orientation is further stabilized by an interaction between the ligand and the membrane. Our findings highlight the diversity in RTK oligomerization and activation mechanisms.
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13
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Alvarez-Sieiro P, Sikkema HR, Poolman B. Heterodimer Formation of the Homodimeric ABC Transporter OpuA. Int J Mol Sci 2021; 22:ijms22115912. [PMID: 34072847 PMCID: PMC8199443 DOI: 10.3390/ijms22115912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 11/16/2022] Open
Abstract
Many proteins have a multimeric structure and are composed of two or more identical subunits. While this can be advantageous for the host organism, it can be a challenge when targeting specific residues in biochemical analyses. In vitro splitting and re-dimerization to circumvent this problem is a tedious process that requires stable proteins. We present an in vivo approach to transform homodimeric proteins into apparent heterodimers, which then can be purified using two-step affinity-tag purification. This opens the door to both practical applications such as smFRET to probe the conformational dynamics of homooligomeric proteins and fundamental research into the mechanism of protein multimerization, which is largely unexplored for membrane proteins. We show that expression conditions are key for the formation of heterodimers and that the order of the differential purification and reconstitution of the protein into nanodiscs is important for a functional ABC-transporter complex.
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14
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Isothermal Titration Calorimetry of Membrane Proteins. Methods Mol Biol 2021. [PMID: 33877623 DOI: 10.1007/978-1-0716-1394-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The ability to quantify protein-protein interactions without adding labels to protein has made isothermal titration calorimetry (ITC) a preferred technique to study proteins in aqueous solution. Here, we describe the application of ITC to the study of protein-protein interactions in membrane mimics using the association of integrin αIIb and β3 transmembrane domains in phospholipid bicelles as an example. A higher conceptual and experimental effort compared to water-soluble proteins is required for membrane proteins and rewarded with rare thermodynamic insight into this central class of proteins.
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15
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Koyama-Honda I, Fujiwara TK, Kasai RS, Suzuki KGN, Kajikawa E, Tsuboi H, Tsunoyama TA, Kusumi A. High-speed single-molecule imaging reveals signal transduction by induced transbilayer raft phases. J Cell Biol 2021; 219:211461. [PMID: 33053147 PMCID: PMC7563750 DOI: 10.1083/jcb.202006125] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/09/2020] [Accepted: 09/14/2020] [Indexed: 12/21/2022] Open
Abstract
Using single-molecule imaging with enhanced time resolutions down to 5 ms, we found that CD59 cluster rafts and GM1 cluster rafts were stably induced in the outer leaflet of the plasma membrane (PM), which triggered the activation of Lyn, H-Ras, and ERK and continually recruited Lyn and H-Ras right beneath them in the inner leaflet with dwell lifetimes <0.1 s. The detection was possible due to the enhanced time resolutions employed here. The recruitment depended on the PM cholesterol and saturated alkyl chains of Lyn and H-Ras, whereas it was blocked by the nonraftophilic transmembrane protein moiety and unsaturated alkyl chains linked to the inner-leaflet molecules. Because GM1 cluster rafts recruited Lyn and H-Ras as efficiently as CD59 cluster rafts, and because the protein moieties of Lyn and H-Ras were not required for the recruitment, we conclude that the transbilayer raft phases induced by the outer-leaflet stabilized rafts recruit lipid-anchored signaling molecules by lateral raft-lipid interactions and thus serve as a key signal transduction platform.
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Affiliation(s)
- Ikuko Koyama-Honda
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Takahiro K Fujiwara
- Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan
| | - Rinshi S Kasai
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Kenichi G N Suzuki
- Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan.,Institute for Glyco-core Research, Gifu University, Nagoya, Japan.,Center for Highly Advanced Integration of Nano and Life Sciences, Gifu University, Gifu, Japan
| | - Eriko Kajikawa
- Laboratory for Organismal Patterning, Center for Biosystems Dynamics Research, RIKEN Kobe, Kobe, Japan
| | - Hisae Tsuboi
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan
| | - Taka A Tsunoyama
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan
| | - Akihiro Kusumi
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan
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16
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Löwe M, Kalacheva M, Boersma AJ, Kedrov A. The more the merrier: effects of macromolecular crowding on the structure and dynamics of biological membranes. FEBS J 2020; 287:5039-5067. [DOI: 10.1111/febs.15429] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Maryna Löwe
- Synthetic Membrane Systems Institute of Biochemistry Heinrich Heine University Düsseldorf Germany
| | | | | | - Alexej Kedrov
- Synthetic Membrane Systems Institute of Biochemistry Heinrich Heine University Düsseldorf Germany
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17
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Analysis of RAS protein interactions in living cells reveals a mechanism for pan-RAS depletion by membrane-targeted RAS binders. Proc Natl Acad Sci U S A 2020; 117:12121-12130. [PMID: 32424096 DOI: 10.1073/pnas.2000848117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
HRAS, NRAS, and KRAS4A/KRAS4B comprise the RAS family of small GTPases that regulate signaling pathways controlling cell proliferation, differentiation, and survival. RAS pathway abnormalities cause developmental disorders and cancers. We found that KRAS4B colocalizes on the cell membrane with other RAS isoforms and a subset of prenylated small GTPase family members using a live-cell quantitative split luciferase complementation assay. RAS protein coclustering is mainly mediated by membrane association-facilitated interactions (MAFIs). Using the RAS-RBD (CRAF RAS binding domain) interaction as a model system, we showed that MAFI alone is not sufficient to induce RBD-mediated RAS inhibition. Surprisingly, we discovered that high-affinity membrane-targeted RAS binding proteins inhibit RAS activity and deplete RAS proteins through an autophagosome-lysosome-mediated degradation pathway. Our results provide a mechanism for regulating RAS activity and protein levels, a more detailed understanding of which should lead to therapeutic strategies for inhibiting and depleting oncogenic RAS proteins.
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18
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Westerfield JM, Barrera FN. Membrane receptor activation mechanisms and transmembrane peptide tools to elucidate them. J Biol Chem 2019; 295:1792-1814. [PMID: 31879273 DOI: 10.1074/jbc.rev119.009457] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Single-pass membrane receptors contain extracellular domains that respond to external stimuli and transmit information to intracellular domains through a single transmembrane (TM) α-helix. Because membrane receptors have various roles in homeostasis, signaling malfunctions of these receptors can cause disease. Despite their importance, there is still much to be understood mechanistically about how single-pass receptors are activated. In general, single-pass receptors respond to extracellular stimuli via alterations in their oligomeric state. The details of this process are still the focus of intense study, and several lines of evidence indicate that the TM domain (TMD) of the receptor plays a central role. We discuss three major mechanistic hypotheses for receptor activation: ligand-induced dimerization, ligand-induced rotation, and receptor clustering. Recent observations suggest that receptors can use a combination of these activation mechanisms and that technical limitations can bias interpretation. Short peptides derived from receptor TMDs, which can be identified by screening or rationally developed on the basis of the structure or sequence of their targets, have provided critical insights into receptor function. Here, we explore recent evidence that, depending on the target receptor, TMD peptides cannot only inhibit but also activate target receptors and can accommodate novel, bifunctional designs. Furthermore, we call for more sharing of negative results to inform the TMD peptide field, which is rapidly transforming into a suite of unique tools with the potential for future therapeutics.
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Affiliation(s)
- Justin M Westerfield
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996.
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19
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Conformational switching of chiral colloidal rafts regulates raft-raft attractions and repulsions. Proc Natl Acad Sci U S A 2019; 116:15792-15801. [PMID: 31320590 DOI: 10.1073/pnas.1900615116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membrane-mediated particle interactions depend both on the properties of the particles themselves and the membrane environment in which they are suspended. Experiments have shown that chiral rod-like inclusions dissolved in a colloidal membrane of opposite handedness assemble into colloidal rafts, which are finite-sized reconfigurable droplets consisting of a large but precisely defined number of rods. We systematically tune the chirality of the background membrane and find that, in the achiral limit, colloidal rafts acquire complex structural properties and interactions. In particular, rafts can switch between 2 chiral states of opposite handedness, which alters the nature of the membrane-mediated raft-raft interactions. Rafts with the same chirality have long-ranged repulsions, while those with opposite chirality acquire attractions with a well-defined minimum. Both attractive and repulsive interactions are qualitatively explained by a continuum model that accounts for the coupling between the membrane thickness and the local tilt of the constituent rods. These switchable interactions enable assembly of colloidal rafts into intricate higher-order architectures, including stable tetrameric clusters and "ionic crystallites" of counter-twisting domains organized on a binary square lattice. Furthermore, the properties of individual rafts, such as their sizes, are controlled by their complexation with other rafts. The emergence of these complex behaviors can be rationalized purely in terms of generic couplings between compositional and orientational order of fluids of rod-like elements. Thus, the uncovered principles might have relevance for conventional lipid bilayers, in which the assembly of higher-order structures is also mediated by complex membrane-mediated interactions.
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20
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Chung JK, Nocka LM, Decker A, Wang Q, Kadlecek TA, Weiss A, Kuriyan J, Groves JT. Switch-like activation of Bruton's tyrosine kinase by membrane-mediated dimerization. Proc Natl Acad Sci U S A 2019; 116:10798-10803. [PMID: 31076553 PMCID: PMC6561188 DOI: 10.1073/pnas.1819309116] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The transformation of molecular binding events into cellular decisions is the basis of most biological signal transduction. A fundamental challenge faced by these systems is that reliance on protein-ligand chemical affinities alone generally results in poor sensitivity to ligand concentration, endangering the system to error. Here, we examine the lipid-binding pleckstrin homology and Tec homology (PH-TH) module of Bruton's tyrosine kinase (Btk). Using fluorescence correlation spectroscopy (FCS) and membrane-binding kinetic measurements, we identify a phosphatidylinositol (3-5)-trisphosphate (PIP3) sensing mechanism that achieves switch-like sensitivity to PIP3 levels, surpassing the intrinsic affinity discrimination of PIP3:PH binding. This mechanism employs multiple PIP3 binding as well as dimerization of Btk on the membrane surface. Studies in live cells confirm that mutations at the dimer interface and peripheral site produce effects comparable to that of the kinase-dead Btk in vivo. These results demonstrate how a single protein module can institute an allosteric counting mechanism to achieve high-precision discrimination of ligand concentration. Furthermore, this activation mechanism distinguishes Btk from other Tec family member kinases, Tec and Itk, which we show are not capable of dimerization through their PH-TH modules. This suggests that Btk plays a critical role in the stringency of the B cell response, whereas T cells rely on other mechanisms to achieve stringency.
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Affiliation(s)
- Jean K Chung
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Laura M Nocka
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Aubrianna Decker
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Qi Wang
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Theresa A Kadlecek
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
| | - Arthur Weiss
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
- Division of Rheumatology, Department of Medicine, University of California, San Francisco, CA 94143
- The Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
| | - John Kuriyan
- Department of Chemistry, University of California, Berkeley, CA 94720;
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, CA 94720;
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21
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Abstract
Bruton’s tyrosine kinase (Btk) activation on the cell membrane is critical for B cell proliferation and development, and Btk inhibition is a promising treatment for several hematologic cancers and autoimmune diseases. Here, we examine Btk activation using the results of long-timescale molecular dynamics simulations. In our simulations, Btk lipid-binding modules dimerized on the membrane in a single predominant conformation. We observed that the phospholipid PIP3—in addition to its expected role of recruiting Btk to the membrane—allosterically mediated dimer formation and stability by binding at two novel sites. Our results provide strong evidence that PIP3-mediated dimerization of Btk at the cell membrane is a critical step in Btk activation and suggest a potential approach to allosteric Btk inhibitor development. Bruton’s tyrosine kinase (Btk) is critical for B cell proliferation and activation, and the development of Btk inhibitors is a vigorously pursued strategy for the treatment of various B cell malignancies. A detailed mechanistic understanding of Btk activation has, however, been lacking. Here, inspired by a previous suggestion that Btk activation might depend on dimerization of its lipid-binding PH–TH module on the cell membrane, we performed long-timescale molecular dynamics simulations of membrane-bound PH–TH modules and observed that they dimerized into a single predominant conformation. We found that the phospholipid PIP3 stabilized the dimer allosterically by binding at multiple sites, and that the effects of PH–TH mutations on dimer stability were consistent with their known effects on Btk activity. Taken together, our simulation results strongly suggest that PIP3-mediated dimerization of Btk at the cell membrane is a critical step in Btk activation.
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22
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Riley TP, Baker BM. The intersection of affinity and specificity in the development and optimization of T cell receptor based therapeutics. Semin Cell Dev Biol 2018; 84:30-41. [DOI: 10.1016/j.semcdb.2017.10.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 10/07/2017] [Accepted: 10/17/2017] [Indexed: 12/29/2022]
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23
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Schavemaker PE, Boersma AJ, Poolman B. How Important Is Protein Diffusion in Prokaryotes? Front Mol Biosci 2018; 5:93. [PMID: 30483513 PMCID: PMC6243074 DOI: 10.3389/fmolb.2018.00093] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 10/22/2018] [Indexed: 12/31/2022] Open
Abstract
That diffusion is important for the proper functioning of cells is without question. The extent to which the diffusion coefficient is important is explored here for prokaryotic cells. We discuss the principles of diffusion focusing on diffusion-limited reactions, summarize the known values for diffusion coefficients in prokaryotes and in in vitro model systems, and explain a number of cases where diffusion coefficients are either limiting for reaction rates or necessary for the existence of phenomena. We suggest a number of areas that need further study including expanding the range of organism growth temperatures, direct measurements of diffusion limitation, expanding the range of cell sizes, diffusion limitation for membrane proteins, and taking into account cellular context when assessing the possibility of diffusion limitation.
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Affiliation(s)
- Paul E Schavemaker
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Arnold J Boersma
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
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24
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Zhang B, Tan J, Li C, Zhang J, Ye S. Amide I SFG Spectral Line Width Probes the Lipid-Peptide and Peptide-Peptide Interactions at Cell Membrane In Situ and in Real Time. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7554-7560. [PMID: 29804455 DOI: 10.1021/acs.langmuir.8b00946] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The balance of lipid-peptide and peptide-peptide interactions at cell membrane is essential to a large variety of cellular processes. In this study, we have experimentally demonstrated for the first time that sum frequency generation vibrational spectroscopy can be used to probe the peptide-peptide and lipid-peptide interactions in cell membrane in situ and in real time by determination of the line width of amide I band of protein backbone. Using a "benchmark" model of α-helical WALP23, it is found that the dominated lipid-peptide interaction causes a narrow line width of the amide I band, whereas the peptide-peptide interaction can markedly broaden the line width. When WALP23 molecules insert into the lipid bilayer, a quite narrow line width of the amide I band is observed because of the lipid-peptide interaction. In contrast, when the peptide lies down on the bilayer surface, the line width of amide I band becomes very broad owing to the peptide-peptide interaction. In terms of the real-time change in the line width, the transition from peptide-peptide interaction to lipid-peptide interaction is monitored during the insertion of WALP23 into 1,2-dipalmitoyl- sn-glycero-3-phospho-(1'- rac-glycerol) (DPPG) lipid bilayer. The dephasing time of a pure α-helical WALP23 in 1-palmitoyl-2-oleoyl- sn-glycero-3-phospho-(1'- rac-glycerol) and DPPG bilayer is determined to be 2.2 and 0.64 ps, respectively. The peptide-peptide interaction can largely accelerate the dephasing time.
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25
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Situ AJ, Kang SM, Frey BB, An W, Kim C, Ulmer TS. Membrane Anchoring of α-Helical Proteins: Role of Tryptophan. J Phys Chem B 2018; 122:1185-1194. [PMID: 29323921 PMCID: PMC11025564 DOI: 10.1021/acs.jpcb.7b11227] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The function of membrane proteins relies on a defined orientation of protein relative to lipid. In apparent correlation to protein anchoring, tryptophan residues are enriched in the lipid headgroup region. To characterize the thermodynamic and structural basis of this relationship in α-helical membrane proteins, we examined the role of three conserved tryptophans in the folding of the heterodimeric integrin αIIbβ3 transmembrane (TM) complex in phospholipid bicelles and mammalian membranes. In the homogenous lipid environment of bicelles, tryptophan was replaceable by residues of distinct polarities. The appropriate polarity was guided by the electrostatic potential of the tryptophan surrounding, suggesting that tryptophan can complement diverse environments by adjusting the orientation of its anisotropic side chain to achieve site-specific anchoring. As a sole membrane anchor, tryptophan made a contribution of 0.4 kcal/mol to TM complex stability in bicelles. In membranes, it proved more difficult to replace tryptophan even by tyrosine, indicating a superior capacity to interact with heterogeneous lipids of biological membranes. Interestingly, at intracellular TM helix ends, where integrin activation is initiated, sequence motifs that interact with lipids via opposing polarity patterns were found to restrict TM helix orientations beyond tryptophan anchoring. In contrast to bicelles, phenylalanine became the least accepted substitute in membranes, demonstrating an increased role of the hydrophobic effect. Altogether, our study implicates a wide amphiphilic range of tryptophan, membrane complexity, and the hydrophobic effect to be important factors in tryptophan membrane anchoring.
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Affiliation(s)
- Alan J Situ
- Department of Biochemistry & Molecular Medicine and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , 1501 San Pablo Street, Los Angeles, California 90033, United States
| | - So-Min Kang
- Department of Life Sciences, Korea University , 145 Anam-Ro, Seongbuk-Gu, Seoul 136-701, South Korea
| | - Benjamin B Frey
- Department of Biochemistry & Molecular Medicine and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , 1501 San Pablo Street, Los Angeles, California 90033, United States
| | - Woojin An
- Department of Biochemistry & Molecular Medicine and Norris Comprehensive Cancer Center, University of Southern California , Los Angeles, California 90033, United States
| | - Chungho Kim
- Department of Life Sciences, Korea University , 145 Anam-Ro, Seongbuk-Gu, Seoul 136-701, South Korea
| | - Tobias S Ulmer
- Department of Biochemistry & Molecular Medicine and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , 1501 San Pablo Street, Los Angeles, California 90033, United States
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26
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Singh NK, Riley TP, Baker SCB, Borrman T, Weng Z, Baker BM. Emerging Concepts in TCR Specificity: Rationalizing and (Maybe) Predicting Outcomes. THE JOURNAL OF IMMUNOLOGY 2017; 199:2203-2213. [PMID: 28923982 DOI: 10.4049/jimmunol.1700744] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/10/2017] [Indexed: 12/14/2022]
Abstract
T cell specificity emerges from a myriad of processes, ranging from the biological pathways that control T cell signaling to the structural and physical mechanisms that influence how TCRs bind peptides and MHC proteins. Of these processes, the binding specificity of the TCR is a key component. However, TCR specificity is enigmatic: TCRs are at once specific but also cross-reactive. Although long appreciated, this duality continues to puzzle immunologists and has implications for the development of TCR-based therapeutics. In this review, we discuss TCR specificity, emphasizing results that have emerged from structural and physical studies of TCR binding. We show how the TCR specificity/cross-reactivity duality can be rationalized from structural and biophysical principles. There is excellent agreement between predictions from these principles and classic predictions about the scope of TCR cross-reactivity. We demonstrate how these same principles can also explain amino acid preferences in immunogenic epitopes and highlight opportunities for structural considerations in predictive immunology.
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Affiliation(s)
- Nishant K Singh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556.,Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556; and
| | - Timothy P Riley
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556.,Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556; and
| | - Sarah Catherine B Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556.,Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556; and
| | - Tyler Borrman
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556; .,Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556; and
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27
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Yom-Tov G, Barak R, Matalon O, Barda-Saad M, Guez-Haddad J, Opatowsky Y. Robo Ig4 Is a Dimerization Domain. J Mol Biol 2017; 429:3606-3616. [PMID: 29017837 DOI: 10.1016/j.jmb.2017.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/02/2017] [Accepted: 10/02/2017] [Indexed: 01/06/2023]
Abstract
Robo receptors play pivotal roles in axonal guidance as well as in neurogenesis, angiogenesis, cell migration, and cancer progression and invasiveness. They are considered to be attractive drug targets for the treatment of cancer, ocular neovascular disorders, chronic kidney diseases, and more. Despite their great importance, the mechanisms by which Robo receptors switch from their "off" to "on" states remain obscure. One possibility involves a monomer-to-dimer or dimer-to-monomer transition that facilitates the recruitment and activation of enzymatic effectors to instigate intracellular signaling. However, it is not known which domains mediate Robo dimerization, or the structural properties of the dimeric interactions. Here, we identify the extracellular Ig4 (D4) as a Robo dimerization domain. We have determined the crystal structure of the tandem Ig4-5 domains (D4-5) of human Robo2 and found that a hydrophobic surface on D4 mediates close homotypic contacts with a reciprocal D4. Analytical ultracentrifugation measurements of intact and mutated D4-5 shows that dimerization through the D4 interface is specific and has a dimerization dissociation constant of 16.9μM in solution. Direct fluorescence resonance energy transfer dimerization measurements in HEK293 cells corroborate the dimerization of transmembrane hRobo2 through D4, and a functional COS-7 cell collapse assay links D4-mediated dimerization with Robo intracellular signaling. The high level of conservation in the D4 dimerization interface throughout all Robo orthologs and paralogs implies that D4-mediated dimerization is a central hallmark in Robo activation and signaling.
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Affiliation(s)
- Galit Yom-Tov
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Reut Barak
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Omri Matalon
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Mira Barda-Saad
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Julia Guez-Haddad
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yarden Opatowsky
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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28
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Multiscale Modeling of Diffusion in a Crowded Environment. Bull Math Biol 2017; 79:2672-2695. [PMID: 28924915 DOI: 10.1007/s11538-017-0346-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 09/06/2017] [Indexed: 10/18/2022]
Abstract
We present a multiscale approach to model diffusion in a crowded environment and its effect on the reaction rates. Diffusion in biological systems is often modeled by a discrete space jump process in order to capture the inherent noise of biological systems, which becomes important in the low copy number regime. To model diffusion in the crowded cell environment efficiently, we compute the jump rates in this mesoscopic model from local first exit times, which account for the microscopic positions of the crowding molecules, while the diffusing molecules jump on a coarser Cartesian grid. We then extract a macroscopic description from the resulting jump rates, where the excluded volume effect is modeled by a diffusion equation with space-dependent diffusion coefficient. The crowding molecules can be of arbitrary shape and size, and numerical experiments demonstrate that those factors together with the size of the diffusing molecule play a crucial role on the magnitude of the decrease in diffusive motion. When correcting the reaction rates for the altered diffusion we can show that molecular crowding either enhances or inhibits chemical reactions depending on local fluctuations of the obstacle density.
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Cai Y, Liu Y, Culhane KJ, DeVree BT, Yang Y, Sunahara RK, Yan ECY. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor. PLoS One 2017; 12:e0179568. [PMID: 28609478 PMCID: PMC5469476 DOI: 10.1371/journal.pone.0179568] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/31/2017] [Indexed: 12/16/2022] Open
Abstract
Family B G protein-coupled receptors (GPCRs) play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1) receptor (GLP1R), whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL) particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms.
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Affiliation(s)
- Yingying Cai
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
| | - Yuting Liu
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
| | - Kelly J. Culhane
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Brian T. DeVree
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Yang Yang
- Nanobiology Institute, Yale University, New Haven, Connecticut, United States of America
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Roger K. Sunahara
- Department of Pharmacology, University of California at San Diego, La Jolla, California, United States of America
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
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Abstract
Tie1 and Tie2, members of the tyrosine kinase family with immunoglobulin and EGF homology domains, are receptor tyrosine kinases found primarily in endothelial cells with key roles in development and maintenance of the vasculature and in angiogenesis. They are attractive targets for therapeutic intervention in tumor angiogenesis, inflammation, and sepsis. Tie2 is regulated directly by the multimeric angiopoietin (Ang) ligands, with Ang1 being its primary activator. Structural studies have shown how Angs bind to the Tie2 ligand-binding region, but do not explain Tie2 activation and suggest a passive role for the Tie2 extracellular region (ECR) in ligand-induced receptor dimerization. Here we show that the Tie2 ECR forms strong dimers even in the absence of bound ligand. Dimerization is mediated by membrane-proximal fibronectin type III (FNIII) domains that were omitted in previous structural studies. We describe a 2.5-Å resolution X-ray crystal structure of the membrane-proximal three Tie2 FNIII domains, Tie2(FNIIIa-c), revealing two possible dimerization modes that primarily involve the third FNIII domain, FNIIIc. Mutating these dimer interfaces implicates one of them (dimer 1) in soluble Tie2 (sTie2) dimerization in solution but suggests that both could play a role in Ang1-induced Tie2 activation, possibly modulated by Tie1. Through small-angle X-ray scattering studies of sTie2 dimers in solution and modeling based on crystal structures, we suggest that Ang1 binding may cross-link Tie2 dimers into higher-order oligomers, potentially explaining how Tie2 is differentially clustered following ligand engagement in different cellular contexts. Our results also firmly implicate FNIII domain-mediated interactions in Tie2 activation, identifying a potential Achilles' heel for therapeutic inhibition.
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Meinecke L, Eriksson M. Excluded volume effects in on- and off-lattice reaction-diffusion models. IET Syst Biol 2017; 11:55-64. [PMID: 28476973 PMCID: PMC8687331 DOI: 10.1049/iet-syb.2016.0021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 04/05/2024] Open
Abstract
Mathematical models are important tools to study the excluded volume effects on reaction-diffusion systems, which are known to play an important role inside living cells. Detailed microscopic simulations with off-lattice Brownian dynamics become computationally expensive in crowded environments. In this study, the authors therefore investigate to which extent on-lattice approximations, the so-called cellular automata models, can be used to simulate reactions and diffusion in the presence of crowding molecules. They show that the diffusion is most severely slowed down in the off-lattice model, since randomly distributed obstacles effectively exclude more volume than those ordered on an artificial grid. Crowded reaction rates can be both increased and decreased by the grid structure and it proves important to model the molecules with realistic sizes when excluded volume is taken into account. The grid artefacts increase with increasing crowder density and they conclude that the computationally more efficient on-lattice simulations are accurate approximations only for low crowder densities.
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Affiliation(s)
- Lina Meinecke
- Department of Information Technology, Uppsala University, Uppsala, Sweden.
| | - Markus Eriksson
- Department of Information Technology, Uppsala University, Uppsala, Sweden
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Hassanin M, Kerek E, Chiu M, Anikovskiy M, Prenner EJ. Binding Affinity of Inorganic Mercury and Cadmium to Biomimetic Erythrocyte Membranes. J Phys Chem B 2016; 120:12872-12882. [DOI: 10.1021/acs.jpcb.6b10366] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mohamed Hassanin
- Department
of Biological Sciences and ‡Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Evan Kerek
- Department
of Biological Sciences and ‡Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Michael Chiu
- Department
of Biological Sciences and ‡Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Max Anikovskiy
- Department
of Biological Sciences and ‡Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Elmar J. Prenner
- Department
of Biological Sciences and ‡Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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Singh DR, Ahmed F, Paul MD, Gedam M, Pasquale EB, Hristova K. The SAM domain inhibits EphA2 interactions in the plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:31-38. [PMID: 27776928 DOI: 10.1016/j.bbamcr.2016.10.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/26/2016] [Accepted: 10/18/2016] [Indexed: 11/18/2022]
Abstract
All members of the Eph receptor family of tyrosine kinases contain a SAM domain near the C terminus, which has been proposed to play a role in receptor homotypic interactions and/or interactions with binding partners. The SAM domain of EphA2 is known to be important for receptor function, but its contribution to EphA2 lateral interactions in the plasma membrane has not been determined. Here we use a FRET-based approach to directly measure the effect of the SAM domain on the stability of EphA2 dimers on the cell surface in the absence of ligand binding. We also investigate the functional consequences of EphA2 SAM domain deletion. Surprisingly, we find that the EphA2 SAM domain inhibits receptor dimerization and decreases EphA2 tyrosine phosphorylation. This role is dramatically different from the role of the SAM domain of the related EphA3 receptor, which we previously found to stabilize EphA3 dimers and increase EphA3 tyrosine phosphorylation in cells in the absence of ligand. Thus, the EphA2 SAM domain likely contributes to a unique mode of EphA2 interaction that leads to distinct signaling outputs.
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Affiliation(s)
- Deo R Singh
- Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, MD 21218, United States
| | - Fozia Ahmed
- Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, MD 21218, United States
| | - Michael D Paul
- Program in Molecular Biophysics, Johns Hopkins University, 3400 Charles street, Baltimore, MD 21218, United States
| | - Manasee Gedam
- Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, MD 21218, United States
| | - Elena B Pasquale
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Road, La Jolla, San Diego, CA 92037, United States
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, MD 21218, United States; Program in Molecular Biophysics, Johns Hopkins University, 3400 Charles street, Baltimore, MD 21218, United States.
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On the mobility, membrane location and functionality of mechanosensitive channels in Escherichia coli. Sci Rep 2016; 6:32709. [PMID: 27596282 PMCID: PMC5011748 DOI: 10.1038/srep32709] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/12/2016] [Indexed: 11/23/2022] Open
Abstract
Bacterial mechanosensitive channels protect cells from structural damage during hypoosmotic shock. MscS, MscL and MscK are the most abundant channels in E. coli and arguably the most important ones in osmoprotection. By combining physiological assays with quantitative photo-activated localization microscopy (qPALM), we find an almost linear relationship between channel abundance and cell survival. A minimum of 100 MscL (or MscS) channels is needed for protection when a single type of channel is expressed. Under native-like conditions MscL, MscS as well as MscK distribute homogeneously over the cytoplasmic membrane and the lateral diffusion of the channels is in accordance with their relative protein mass. However, we observe cluster formation and a reduced mobility of MscL when the majority of the subunits of the pentameric channel contain the fluorescent mEos3.2 protein. These data provide new insights into the quantitative biology of mechanosensitive channels and emphasizes the need for care in analysing protein complexes even when the fluorescent tag has been optimized for monomeric behaviour.
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Heaton NS, Moshkina N, Fenouil R, Gardner TJ, Aguirre S, Shah PS, Zhao N, Manganaro L, Hultquist JF, Noel J, Sachs D, Hamilton J, Leon PE, Chawdury A, Tripathi S, Melegari C, Campisi L, Hai R, Metreveli G, Gamarnik AV, García-Sastre A, Greenbaum B, Simon V, Fernandez-Sesma A, Krogan NJ, Mulder LCF, van Bakel H, Tortorella D, Taunton J, Palese P, Marazzi I. Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection. Immunity 2016; 44:46-58. [PMID: 26789921 DOI: 10.1016/j.immuni.2015.12.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 12/22/2022]
Abstract
Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies.
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Affiliation(s)
- Nicholas S Heaton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Natasha Moshkina
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Romain Fenouil
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Thomas J Gardner
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Sebastian Aguirre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Priya S Shah
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Nan Zhao
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Lara Manganaro
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Judd F Hultquist
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Justine Noel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - David Sachs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jennifer Hamilton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Paul E Leon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Amit Chawdury
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Shashank Tripathi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Camilla Melegari
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Laura Campisi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Rong Hai
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Giorgi Metreveli
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-CONICET, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Benjamin Greenbaum
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Viviana Simon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Lubbertus C F Mulder
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Domenico Tortorella
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Peter Palese
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ivan Marazzi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA.
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Deak PE, Vrabel MR, Pizzuti VJ, Kiziltepe T, Bilgicer B. Nanoallergens: A multivalent platform for studying and evaluating potency of allergen epitopes in cellular degranulation. Exp Biol Med (Maywood) 2016; 241:996-1006. [PMID: 27188517 DOI: 10.1177/1535370216644533] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Degranulation caused by type I hypersensitivity (allergies) is a complex biophysical process, and available experimental models for studying relevant immunoglobulin E binding epitopes on allergen proteins lack the ability to adequately evaluate, rank, and associate these epitopes individually and with each other. In this study, we propose a new allergy model system for studying potential allergen epitopes using nanoallergens, liposomes modified to effectively display IgE binding epitopes/haptens. By utilizing the covalently conjugated lipid tails on two hapten molecules (dinitrophenol and dansyl), hapten molecules were successfully incorporated into liposomes with high precision to form nanoallergens. Nanoallergens, with precisely controlled high-particle valency, can trigger degranulation with much greater sensitivity than commonly used bovine serum albumin conjugates. In rat basophil leukemia cell experiments, nanoallergens with only 2% hapten loading were able to trigger degranulation in vitro at concentrations as low as 10 pM. Additionally, unlike bovine serum albumin-hapten conjugates, nanoallergens allow exact control over particle size and valency. By varying the nanoallergen parameters such as size, valency, monovalent affinity of hapten, and specific IgE ratios, we exposed the importance of these variables on degranulation intensity while demonstrating nanoallergens' potential for evaluating both high- and low-affinity epitopes. The data presented in this article establish nanoallergen platform as a reliable and versatile allergy model to study and evaluate allergen epitopes in mast cell degranulation.
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Affiliation(s)
- Peter E Deak
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, IN 46556, USA
| | - Maura R Vrabel
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, IN 46556, USA
| | - Vincenzo J Pizzuti
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, IN 46556, USA
| | - Tanyel Kiziltepe
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, IN 46556, USA Advanced Diagnostics and Therapeutics, University of Notre Dame, IN 46556, USA
| | - Basar Bilgicer
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, IN 46556, USA Advanced Diagnostics and Therapeutics, University of Notre Dame, IN 46556, USA Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556, USA
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King C, Stoneman M, Raicu V, Hristova K. Fully quantified spectral imaging reveals in vivo membrane protein interactions. Integr Biol (Camb) 2016; 8:216-29. [PMID: 26787445 DOI: 10.1039/c5ib00202h] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Here we introduce the fully quantified spectral imaging (FSI) method as a new tool to probe the stoichiometry and stability of protein complexes in biological membranes. The FSI method yields two dimensional membrane concentrations and FRET efficiencies in native plasma membranes. It can be used to characterize the association of membrane proteins: to differentiate between monomers, dimers, or oligomers, to produce binding (association) curves, and to measure the free energies of association in the membrane. We use the FSI method to study the lateral interactions of Vascular Endothelial Growth Factor Receptor 2 (VEGFR2), a member of the receptor tyrosine kinase (RTK) superfamily, in plasma membranes, in vivo. The knowledge gained through the use of the new method challenges the current understanding of VEGFR2 signaling.
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Affiliation(s)
- Christopher King
- Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21212, USA
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38
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Angeles-Martinez L, Theodoropoulos C. A Lattice-Boltzmann scheme for the simulation of diffusion in intracellular crowded systems. BMC Bioinformatics 2015; 16:353. [PMID: 26530635 PMCID: PMC4632338 DOI: 10.1186/s12859-015-0769-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 10/08/2015] [Indexed: 11/10/2022] Open
Abstract
Background The intracellular environment is a complex and crowded medium where the diffusion of proteins, metabolites and other molecules can be decreased. One of the most popular methodologies for the simulation of diffusion in crowding systems is the Monte Carlo algorithm (MC) which tracks the movement of each particle. This can, however, be computationally expensive for a system comprising a large number of molecules. On the other hand, the Lattice Boltzmann Method (LBM) tracks the movement of collections of molecules, which represents significant savings in computational time. Nevertheless in the classical manifestation of such scheme the crowding conditions are neglected. Methods In this paper we use Scaled Particle Theory (SPT) to approximate the probability to find free space for the displacement of hard-disk molecules and in this way to incorporate the crowding effect to the LBM. This new methodology which couples SPT and LBM is validated using a kinetic Monte Carlo (kMC) algorithm, which is used here as our "computational experiment". Results The results indicate that LBM over-predicts the diffusion in 2D crowded systems, while the proposed coupled SPT-LBM predicts the same behaviour as the kinetic Monte Carlo (kMC) algorithm but with a significantly reduced computational effort. Despite the fact that small deviations between the two methods were observed, in part due to the mesoscopic and microscopic nature of each method, respectively, the agreement was satisfactory both from a qualitative and a quantitative point of view. Conclusions A crowding-adaptation to LBM has been developed using SPT, allowing fast simulations of diffusion-systems of different size hard-disk molecules in two-dimensional space. This methodology takes into account crowding conditions; not only the space fraction occupied by the crowder molecules but also the influence of the size of the crowder which can affect the displacement of molecules across the lattice system. Electronic supplementary material The online version of this article (doi:10.1186/s12859-015-0769-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Liliana Angeles-Martinez
- School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, M13 9PL, UK.
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39
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Sarabipour S, Del Piccolo N, Hristova K. Characterization of membrane protein interactions in plasma membrane derived vesicles with quantitative imaging Förster resonance energy transfer. Acc Chem Res 2015; 48:2262-9. [PMID: 26244699 PMCID: PMC4841635 DOI: 10.1021/acs.accounts.5b00238] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Here we describe an experimental tool, termed quantitative imaging Förster resonance energy transfer (QI-FRET), that enables the quantitative characterization of membrane protein interactions. The QI-FRET methodology allows us to acquire binding curves and calculate association constants for complex membrane proteins in the native plasma membrane environment. The method utilizes FRET detection, and thus requires that the proteins of interest are labeled with florescent proteins, either FRET donors or FRET acceptors. Since plasma membranes of cells have complex topologies precluding the acquisition of two-dimensional binding curves, the FRET measurements are performed in plasma membrane derived vesicles that bud off cells as a result of chemical or osmotic stress. The results overviewed here are acquired in vesicles produced with an osmotic vesiculation buffer developed in our laboratory, which does not utilize harsh chemicals. The concentrations of the donor-labeled and the acceptor-labeled proteins are determined, along with the FRET efficiencies, in each vesicle. The experiments utilize transient transfection, such that a wide variety of concentrations is sampled. Then, data from hundreds of vesicles are combined to yield dimerization curves. Here we discuss recent findings about the dimerization of receptor tyrosine kinases (RTKs), membrane proteins that control cell growth and differentiation via lateral dimerization in the plasma membrane. We focus on the dimerization of fibroblast growth factor receptor 3 (FGFR3), a RTK that plays a critically important role in skeletal development. We study the role of different FGFR3 domains in FGFR3 dimerization in the absence of ligand, and we show that FGFR3 extracellular domains inhibit unliganded dimerization, while contacts between the juxtamembrane domains, which connect the transmembrane domains to the kinase domains, stabilize the unliganded FGFR3 dimers. Since FGFR3 has been documented to harbor many pathogenic single amino acid mutations that cause skeletal and cranial dysplasias, as well as cancer, we also study the effects of these mutations on dimerization. First, we show that the A391E mutation, linked to Crouzon syndrome with acanthosis nigricans and to bladder cancer, significantly enhances FGFR3 dimerization in the absence of ligand and thus induces aberrant receptor interactions. Second, we present results about the effect of three cysteine mutations that cause thanatophoric dysplasia, a lethal phenotype. Such cysteine mutations have been hypothesized previously to cause constitutive dimerization, but we find instead that they have a surprisingly modest effect on dimerization. Most of the studied pathogenic mutations also altered FGFR3 dimer structure, suggesting that both increases in dimerization propensities and changes in dimer structure contribute to the pathological phenotypes. The results acquired with the QI-FRET method further our understanding of the interactions between FGFR3 molecules and RTK molecules in general. Since RTK dimerization regulates RTK signaling, our findings advance our knowledge of RTK activity in health and disease. The utility of the QI-FRET method is not restricted to RTKs, and we thus hope that in the future the QI-FRET method will be applied to other classes of membrane proteins, such as channels and G protein-coupled receptors.
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MESH Headings
- Acanthosis Nigricans/etiology
- Acanthosis Nigricans/genetics
- Cell Membrane/chemistry
- Cell Membrane/metabolism
- Craniofacial Dysostosis/etiology
- Craniofacial Dysostosis/genetics
- Dimerization
- Fluorescence Resonance Energy Transfer
- Humans
- Mutagenesis, Site-Directed
- Protein Structure, Tertiary
- Receptor, Fibroblast Growth Factor, Type 3/chemistry
- Receptor, Fibroblast Growth Factor, Type 3/deficiency
- Receptor, Fibroblast Growth Factor, Type 3/genetics
- Receptor, Fibroblast Growth Factor, Type 3/metabolism
- Thanatophoric Dysplasia/etiology
- Thanatophoric Dysplasia/genetics
- Transport Vesicles/chemistry
- Transport Vesicles/metabolism
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Affiliation(s)
- Sarvenaz Sarabipour
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Nuala Del Piccolo
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218
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40
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Freed DM, Alvarado D, Lemmon MA. Ligand regulation of a constitutively dimeric EGF receptor. Nat Commun 2015; 6:7380. [PMID: 26060020 PMCID: PMC4465127 DOI: 10.1038/ncomms8380] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 05/01/2015] [Indexed: 12/30/2022] Open
Abstract
Ligand-induced receptor dimerization has traditionally been viewed as the key event in transmembrane signalling by epidermal growth factor receptors (EGFRs). Here we show that the Caenorhabditis elegans EGFR orthologue LET-23 is constitutively dimeric, yet responds to its ligand LIN-3 without changing oligomerization state. SAXS and mutational analyses further reveal that the preformed dimer of the LET-23 extracellular region is mediated by its domain II dimerization arm and resembles other EGFR extracellular dimers seen in structural studies. Binding of LIN-3 induces only minor structural rearrangements in the LET-23 dimer to promote signalling. Our results therefore argue that EGFR can be regulated by allosteric changes within an existing receptor dimer--resembling signalling by insulin receptor family members, which share similar extracellular domain compositions but form covalent dimers.
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Affiliation(s)
- Daniel M. Freed
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, 322A Clinical Research Building, 415 Curie Boulevard, Philadelphia, Pennsylvania 19104-6059, USA
| | - Diego Alvarado
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, 322A Clinical Research Building, 415 Curie Boulevard, Philadelphia, Pennsylvania 19104-6059, USA
| | - Mark A. Lemmon
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, 322A Clinical Research Building, 415 Curie Boulevard, Philadelphia, Pennsylvania 19104-6059, USA
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41
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Sarabipour S, Hristova K. FGFR3 unliganded dimer stabilization by the juxtamembrane domain. J Mol Biol 2015; 427:1705-14. [PMID: 25688803 PMCID: PMC4380549 DOI: 10.1016/j.jmb.2015.02.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/12/2015] [Accepted: 02/11/2015] [Indexed: 11/22/2022]
Abstract
Receptor tyrosine kinases (RTKs) conduct biochemical signals upon dimerization in the membrane plane. While RTKs are generally known to be activated in response to ligand binding, many of these receptors are capable of forming unliganded dimers that are likely important intermediates in the signaling process. All 58 RTKs consist of an extracellular (EC) domain, a transmembrane (TM) domain, and an intracellular domain that includes a juxtamembrane (JM) sequence and a kinase domain. Here we investigate directly the effect of the JM domain on unliganded dimer stability of FGFR3, a receptor that is critically important for skeletal development. The data suggest that FGFR3 unliganded dimers are stabilized by receptor-receptor contacts that involve the JM domains. The contribution is significant, as it is similar in magnitude to the stabilizing contribution of a pathogenic mutation and the repulsive contribution of the EC domain. Furthermore, we show that the effects of the JM domain and a TM pathogenic mutation on unliganded FGFR3 dimer stability are additive. We observe that the JM-mediated dimer stabilization occurs when the JM domain is linked to FGFR3 TM domain and not simply anchored to the plasma membrane. These results point to a coordinated stabilization of the unliganded dimeric state of FGFR3 by its JM and TM domains via a mechanism that is distinctly different from the case of another well studied receptor, EGFR.
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Affiliation(s)
- Sarvenaz Sarabipour
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, USA
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, USA.
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42
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Reshetnyak AV, Opatowsky Y, Boggon TJ, Folta-Stogniew E, Tome F, Lax I, Schlessinger J. The strength and cooperativity of KIT ectodomain contacts determine normal ligand-dependent stimulation or oncogenic activation in cancer. Mol Cell 2014; 57:191-201. [PMID: 25544564 DOI: 10.1016/j.molcel.2014.11.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 10/14/2014] [Accepted: 11/18/2014] [Indexed: 12/22/2022]
Abstract
The receptor tyrosine kinase KIT plays an important role in development of germ cells, hematopoietic cells, and interstitial pacemaker cells. Oncogenic KIT mutations play an important "driver" role in gastrointestinal stromal tumors, acute myeloid leukemias, and melanoma, among other cancers. Here we describe the crystal structure of a recurring somatic oncogenic mutation located in the C-terminal Ig-like domain (D5) of the ectodomain, rendering KIT tyrosine kinase activity constitutively activated. The structural analysis, together with biochemical and biophysical experiments and detailed analyses of the activities of a variety of oncogenic KIT mutations, reveals that the strength of homotypic contacts and the cooperativity in the action of D4D5 regions determines whether KIT is normally regulated or constitutively activated in cancers. We propose that cooperative interactions mediated by multiple weak homotypic contacts between receptor molecules are responsible for regulating normal ligand-dependent or oncogenic RTK activation via a "zipper-like" mechanism for receptor activation.
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Affiliation(s)
- Andrey V Reshetnyak
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Yarden Opatowsky
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ewa Folta-Stogniew
- The Biophysical Resource, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Francisco Tome
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Irit Lax
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Joseph Schlessinger
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.
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43
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Jakob RP, Koch JR, Burmann BM, Schmidpeter PAM, Hunkeler M, Hiller S, Schmid FX, Maier T. Dimeric Structure of the Bacterial Extracellular Foldase PrsA. J Biol Chem 2014; 290:3278-92. [PMID: 25525259 DOI: 10.1074/jbc.m114.622910] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Secretion of proteins into the membrane-cell wall space is essential for cell wall biosynthesis and pathogenicity in Gram-positive bacteria. Folding and maturation of many secreted proteins depend on a single extracellular foldase, the PrsA protein. PrsA is a 30-kDa protein, lipid anchored to the outer leaflet of the cell membrane. The crystal structure of Bacillus subtilis PrsA reveals a central catalytic parvulin-type prolyl isomerase domain, which is inserted into a larger composite NC domain formed by the N- and C-terminal regions. This domain architecture resembles, despite a lack of sequence conservation, both trigger factor, a ribosome-binding bacterial chaperone, and SurA, a periplasmic chaperone in Gram-negative bacteria. Two main structural differences are observed in that the N-terminal arm of PrsA is substantially shortened relative to the trigger factor and SurA and in that PrsA is found to dimerize in a unique fashion via its NC domain. Dimerization leads to a large, bowl-shaped crevice, which might be involved in vivo in protecting substrate proteins from aggregation. NMR experiments reveal a direct, dynamic interaction of both the parvulin and the NC domain with secretion propeptides, which have been implicated in substrate targeting to PrsA.
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Affiliation(s)
- Roman P Jakob
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Johanna R Koch
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Björn M Burmann
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Philipp A M Schmidpeter
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Moritz Hunkeler
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Sebastian Hiller
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Franz X Schmid
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Timm Maier
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
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44
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Folding energetics and oligomerization of polytopic α-helical transmembrane proteins. Arch Biochem Biophys 2014; 564:281-96. [DOI: 10.1016/j.abb.2014.07.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/26/2014] [Accepted: 07/14/2014] [Indexed: 01/06/2023]
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45
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Situ AJ, Schmidt T, Mazumder P, Ulmer TS. Characterization of Membrane Protein Interactions by Isothermal Titration Calorimetry. J Mol Biol 2014; 426:3670-80. [DOI: 10.1016/j.jmb.2014.08.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/18/2014] [Accepted: 08/25/2014] [Indexed: 12/11/2022]
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46
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Liu J, Spulber M, Wu D, Talom RM, Palivan CG, Meier W. Poly(N-isopropylacrylamide-co-tris-nitrilotriacetic acid acrylamide) for a Combined Study of Molecular Recognition and Spatial Constraints in Protein Binding and Interactions. J Am Chem Soc 2014; 136:12607-14. [DOI: 10.1021/ja503632w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Juan Liu
- Department of Chemistry, University of Basel, Klingelbergstrasse
80, Basel 4056, Switzerland
| | - Mariana Spulber
- Department of Chemistry, University of Basel, Klingelbergstrasse
80, Basel 4056, Switzerland
| | - Dalin Wu
- Department of Chemistry, University of Basel, Klingelbergstrasse
80, Basel 4056, Switzerland
| | - Renee M. Talom
- Department of Chemistry, University of Basel, Klingelbergstrasse
80, Basel 4056, Switzerland
| | - Cornelia G. Palivan
- Department of Chemistry, University of Basel, Klingelbergstrasse
80, Basel 4056, Switzerland
| | - Wolfgang Meier
- Department of Chemistry, University of Basel, Klingelbergstrasse
80, Basel 4056, Switzerland
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47
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Chapanian R, Kwan DH, Constantinescu I, Shaikh FA, Rossi NAA, Withers SG, Kizhakkedathu JN. Enhancement of biological reactions on cell surfaces via macromolecular crowding. Nat Commun 2014; 5:4683. [PMID: 25140641 PMCID: PMC4978540 DOI: 10.1038/ncomms5683] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 07/11/2014] [Indexed: 12/18/2022] Open
Abstract
The reaction of macromolecules such as enzymes and antibodies with cell surfaces is often an inefficient process, requiring large amounts of expensive reagent. Here we report a general method based on macromolecular crowding with a range of neutral polymers to enhance such reactions, using red blood cells (RBCs) as a model system. Rates of conversion of type A and B red blood cells to universal O type by removal of antigenic carbohydrates with selective glycosidases are increased up to 400-fold in the presence of crowders. Similar enhancements are seen for antibody binding. We further explore the factors underlying these enhancements using confocal microscopy and fluorescent recovery after bleaching (FRAP) techniques with various fluorescent protein fusion partners. Increased cell-surface concentration due to volume exclusion, along with two-dimensionally confined diffusion of enzymes close to the cell surface, appear to be the major contributing factors.
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Affiliation(s)
- Rafi Chapanian
- 1] Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada V6T 1Z3 [2] Department of Pathology and Laboratory Medicine, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada V6T 1Z3
| | - David H Kwan
- 1] Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1 [2] Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Iren Constantinescu
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada V6T 1Z3
| | - Fathima A Shaikh
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Nicholas A A Rossi
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada V6T 1Z3
| | - Stephen G Withers
- 1] Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1 [2] Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3 [3] Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Jayachandran N Kizhakkedathu
- 1] Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada V6T 1Z3 [2] Department of Pathology and Laboratory Medicine, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada V6T 1Z3 [3] Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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48
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Physical and genetic interaction between ammonium transporters and the signaling protein Rho1 in the plant pathogen Ustilago maydis. EUKARYOTIC CELL 2014; 13:1328-36. [PMID: 25128189 DOI: 10.1128/ec.00150-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dimorphic transitions between yeast-like and filamentous forms occur in many fungi and are often associated with pathogenesis. One of the cues for such a dimorphic switch is the availability of nutrients. Under conditions of nitrogen limitation, fungal cells (such as those of Saccharomyces cerevisiae and Ustilago maydis) switch from budding to pseudohyphal or filamentous growth. Ammonium transporters (AMTs) are responsible for uptake and, in some cases, for sensing the availability of ammonium, a preferred nitrogen source. Homodimer and/or heterodimer formation may be required for regulating the activity of the AMTs. To investigate the potential interactions of Ump1 and Ump2, the AMTs of the maize pathogen U. maydis, we first used the split-ubiquitin system, followed by a modified split-YFP (yellow fluorescent protein) system, to validate the interactions in vivo. This analysis showed the formation of homo- and hetero-oligomers by Ump1 and Ump2. We also demonstrated the interaction of the high-affinity ammonium transporter, Ump2, with the Rho1 GTPase, a central protein in signaling, with roles in controlling polarized growth. This is the first demonstration in eukaryotes of the physical interaction in vivo of an ammonium transporter with the signaling protein Rho1. Moreover, the Ump proteins interact with Rho1 during the growth of cells in low ammonium concentrations, a condition required for the expression of the Umps. Based on these results and the genetic evidence for the interaction of Ump2 with both Rho1 and Rac1, another small GTPase, we propose a model for the role of these interactions in controlling filamentation, a fundamental aspect of development and pathogenesis in U. maydis.
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49
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Tracking single molecules at work in living cells. Nat Chem Biol 2014; 10:524-32. [PMID: 24937070 DOI: 10.1038/nchembio.1558] [Citation(s) in RCA: 221] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/21/2014] [Indexed: 11/09/2022]
Abstract
Methods for imaging and tracking single molecules conjugated with fluorescent probes, called single-molecule tracking (SMT), are now providing researchers with the unprecedented ability to directly observe molecular behaviors and interactions in living cells. Current SMT methods are achieving almost the ultimate spatial precision and time resolution for tracking single molecules, determined by the currently available dyes. In cells, various molecular interactions and reactions occur as stochastic and probabilistic processes. SMT provides an ideal way to directly track these processes by observing individual molecules at work in living cells, leading to totally new views of the biochemical and molecular processes used by cells whether in signal transduction, gene regulation or formation and disintegration of macromolecular complexes. Here we review SMT methods, summarize the recent results obtained by SMT, including related superresolution microscopy data, and describe the special concerns when SMT applications are shifted from the in vitro paradigms to living cells.
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50
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Abstract
Cellular membranes are constantly reshaped by vesicular fission and fusion as well as by interactions with the dynamic cytoskeleton. Signaling activity at membranes depends on their geometric parameters, such as surface area and curvature; these affect local concentration and thereby regulate the potency of molecular reactions. A membrane's shape is thus inextricably tied to information processing. Here, we review how a trinity of signaling, cytoskeletal dynamics, and membrane shape interact within a closed-loop causality that gives rise to an energy-consuming, self-organized system that changes shape to sense the extracellular environment.
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