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Hong X, Song K, Rahman MU, Wei T, Zhang Y, Da LT, Chen HF. Phosphorylation Regulation Mechanism of β2 Integrin for the Binding of Filamin Revealed by Markov State Model. J Chem Inf Model 2023; 63:605-618. [PMID: 36607244 DOI: 10.1021/acs.jcim.2c01177] [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: 01/07/2023]
Abstract
Leukocyte adhesion deficiency-1 (LAD-1) disorder is a severe immunodeficiency syndrome caused by deficiency or mutation of β2 integrin. The phosphorylation on threonine 758 of β2 integrin acts as a molecular switch inhibiting the binding of filamin. However, the switch mechanism of site-specific phosphorylation at the atom level is still poorly understood. To resolve the regulation mechanism, all-atom molecular dynamics simulation and Markov state model were used to study the dynamic regulation pathway of phosphorylation. Wild type system possessed lower binding free energy and fewer number of states than the phosphorylated system. Both systems underwent local disorder-to-order conformation conversion when achieving steady states. To reach steady states, wild type adopted less number of transition paths/shortest path according to the transition path theory than the phosphorylated system. The underlying phosphorylated regulation pathway was from P1 to P0 and then P4 state, and the main driving force should be hydrogen bond and hydrophobic interaction disturbing the secondary structure of phosphorylated states. These studies will shed light on the pathogenesis of LAD-1 disease and lay a foundation for drug development.
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Affiliation(s)
- Xiaokun Hong
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai200240, China
| | - Kaiyuan Song
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai200240, China
| | - Mueed Ur Rahman
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai200240, China
| | - Ting Wei
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai200240, China
| | - Yan Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai200240, China
| | - Lin-Tai Da
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai200240, China
| | - Hai-Feng Chen
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai200240, China
- Shanghai Center for Bioinformation Technology, Shanghai200240, China
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Bhattacharjya S. The structural basis of β2 integrin intra-cellular multi-protein complexes. Biophys Rev 2022; 14:1183-1195. [PMID: 36345283 PMCID: PMC9636337 DOI: 10.1007/s12551-022-00995-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/24/2022] [Indexed: 01/03/2023] Open
Abstract
In multicellular organisms, cell adhesion is a pivotal physiological process which is essential for cell-cell communications, cell migration, and interactions with extracellular matrix. Integrins, a family of large hetero-dimeric type I membrane proteins, are known for driving cell adhesion functions. Among 24 different integrins, four β2 integrins, αL β2, αM β2, αX β2 and αD β2, are specific for cell adhesion and migration of leukocytes. Many cytosolic proteins interact with short cytosolic tails (CTs) of β2 and other integrins which are essential in bi-directional signaling processes. Further, phosphorylation of CTs of integrins regulates binding of intra-cellular proteins and signaling systems. In this review, recent advances in structures and interactions of multi-protein complexes of integrin tails, with a focus on β2 integrin, and cytosolic proteins are discussed along with a proposed future direction.
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Affiliation(s)
- Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
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3
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Gahmberg CG, Grönholm M. How integrin phosphorylations regulate cell adhesion and signaling. Trends Biochem Sci 2021; 47:265-278. [PMID: 34872819 PMCID: PMC8642147 DOI: 10.1016/j.tibs.2021.11.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 12/13/2022]
Abstract
Cell adhesion is essential for the formation of organs, cellular migration, and interaction with target cells and the extracellular matrix. Integrins are large protein α/β-chain heterodimers and form a major family of cell adhesion molecules. Recent research has dramatically increased our knowledge of how integrin phosphorylations regulate integrin activity. Phosphorylations determine the signaling complexes formed on the cytoplasmic tails, regulating downstream signaling. α-Chain phosphorylation is necessary for inducing β-chain phosphorylation in LFA-1, and the crosstalk from one integrin to another activating or inactivating its function is in part mediated by phosphorylation of β-chains. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus receptor angiotensin-converting enzyme 2 (ACE2) and possible integrin coreceptors may crosstalk and induce a phosphorylation switch and autophagy.
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Affiliation(s)
- Carl G Gahmberg
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland.
| | - Mikaela Grönholm
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland; Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, 00014 Helsinki, Finland
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Zhiping LL, Ong LT, Chatterjee D, Tan SM, Bhattacharjya S. Binary and ternary complexes of FLNa-Ig21 with cytosolic tails of αMß2 integrin reveal dual role of filamin mediated regulation. Biochim Biophys Acta Gen Subj 2021; 1865:130005. [PMID: 34509570 DOI: 10.1016/j.bbagen.2021.130005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/25/2021] [Accepted: 09/07/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Cytoskeletal protein filamin A is critical for the outside-in signaling of integrins. Although molecular mechanisms of filamin-integrin interactions are not fully understood. Mostly, the membrane distal (MD) part of the cytosolic tail (CT) of β subunit of integrin is known to interact with filamin A domain 21 (FLNa-Ig2). However, binary and ternary complexes of full-length CTs of leucocyte specific ß2 integrins with FLNa-Ig21 are yet to be elucidated. METHODS Binding interactions of the CTs of integrin αMß2 with FLNa-Ig21 are extensively investigated by NMR, ITC, cell-based functional assays and computational docking. RESULTS The αM CT demonstrates interactions with FLNa-Ig21 forming a binary complex. Filamin/αM interface is mediated by sidechain-sidechain interactions among non-polar and aromatic residues involving MP helix of αM and the canonical CD face of FLNa-Ig21. Functional assays delineated an interfacial residue Y1137 of αM CT is critical for in-cell binding to FLNa-Ig2. In addition, full-length ß2 CT occupies two distinct binding sites in complex with FLNa-Ig21. A ternary complex of FLNa-Ig21 with CTs has been characterized. In the ternary complex, αM CT moves away to a distal site of FLNa-Ig21 with fewer interactions. CONCLUSION Our findings demonstrate a plausible dual role of filamin in integrin regulation. The molecular interactions of the ternary complex are critical for the resting state of integrins whereas stable FLNa-Ig21/αM CT binary complex perhaps be required for the activated state. GENERAL SIGNIFICANCE Filamin binding to both α and β CTs of other integrins could be essential in regulating bidirectional signaling mechanisms.
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Affiliation(s)
- Lewis Lu Zhiping
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Li-Teng Ong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Deepak Chatterjee
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Suet-Mien Tan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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5
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Regulation of cell adhesion: a collaborative effort of integrins, their ligands, cytoplasmic actors, and phosphorylation. Q Rev Biophys 2019; 52:e10. [PMID: 31709962 DOI: 10.1017/s0033583519000088] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Integrins are large heterodimeric type 1 membrane proteins expressed in all nucleated mammalian cells. Eighteen α-chains and eight β-chains can combine to form 24 different integrins. They are cell adhesion proteins, which bind to a large variety of cellular and extracellular ligands. Integrins are required for cell migration, hemostasis, translocation of cells out from the blood stream and further movement into tissues, but also for the immune response and tissue morphogenesis. Importantly, integrins are not usually active as such, but need activation to become adhesive. Integrins are activated by outside-in activation through integrin ligand binding, or by inside-out activation through intracellular signaling. An important question is how integrin activity is regulated, and this topic has recently drawn much attention. Changes in integrin affinity for ligand binding are due to allosteric structural alterations, but equally important are avidity changes due to integrin clustering in the plane of the plasma membrane. Recent studies have partially solved how integrin cell surface structures change during activation. The integrin cytoplasmic domains are relatively short, but by interacting with a variety of cytoplasmic proteins in a regulated manner, the integrins acquire a number of properties important not only for cell adhesion and movement, but also for cellular signaling. Recent work has shown that specific integrin phosphorylations play pivotal roles in the regulation of integrin activity. Our purpose in this review is to integrate the present knowledge to enable an understanding of how cell adhesion is dynamically regulated.
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Kang C. 19F-NMR in Target-based Drug Discovery. Curr Med Chem 2019; 26:4964-4983. [PMID: 31187703 DOI: 10.2174/0929867326666190610160534] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/14/2018] [Accepted: 03/13/2019] [Indexed: 02/06/2023]
Abstract
Solution NMR spectroscopy plays important roles in understanding protein structures, dynamics and protein-protein/ligand interactions. In a target-based drug discovery project, NMR can serve an important function in hit identification and lead optimization. Fluorine is a valuable probe for evaluating protein conformational changes and protein-ligand interactions. Accumulated studies demonstrate that 19F-NMR can play important roles in fragment- based drug discovery (FBDD) and probing protein-ligand interactions. This review summarizes the application of 19F-NMR in understanding protein-ligand interactions and drug discovery. Several examples are included to show the roles of 19F-NMR in confirming identified hits/leads in the drug discovery process. In addition to identifying hits from fluorinecontaining compound libraries, 19F-NMR will play an important role in drug discovery by providing a fast and robust way in novel hit identification. This technique can be used for ranking compounds with different binding affinities and is particularly useful for screening competitive compounds when a reference ligand is available.
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Affiliation(s)
- CongBao Kang
- Experimental Drug Development Centre (EDDC), Agency for Science, Technology and Research (A*STAR), 10 Biopolis Road, #05-01, Singapore, 138670, Singapore
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7
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Lalle M, Fiorillo A. The protein 14-3-3: A functionally versatile molecule in Giardia duodenalis. ADVANCES IN PARASITOLOGY 2019; 106:51-103. [PMID: 31630760 DOI: 10.1016/bs.apar.2019.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Giardia duodenalis is a cosmopolitan zoonotic protozoan parasite causing giardiasis, one of the most common diarrhoeal diseases in human and animals. Beyond its public health relevance, Giardia represents a valuable and fascinating model microorganism. The deep-branching phylogenetic position of Giardia, its simple life cycle and its minimalistic genomic and cellular organization provide a unique opportunity to define basal and "ancestral" eukaryotic functions. The eukaryotic 14-3-3 protein family represents a distinct example of phosphoserine/phosphothreonine-binding proteins. The extended network of protein-protein interactions established by 14-3-3 proteins place them at the crossroad of multiple signalling pathways that regulate physiological and pathological cellular processes. Despite the remarkable insight on 14-3-3 protein in different organisms, from yeast to humans, so far little attention was given to the study of this protein in protozoan parasites. However, in the last years, research efforts have provided evidences on unique properties of the single 14-3-3 protein of Giardia and on its association in key aspects of Giardia life cycle. In the first part of this chapter, a general overview of the features commonly shared among 14-3-3 proteins in different organisms (i.e. structure, target recognition, mode of action and regulatory mechanisms) is included. The second part focus on the current knowledge on the biochemistry and biology of the Giardia 14-3-3 protein and on the possibility to use this protein as target to propose new strategies for developing innovative antigiardial therapy.
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Affiliation(s)
- Marco Lalle
- Department of Infectious Diseases, European Union Reference Laboratory for Parasites, Istituto Superiore di Sanità, Rome, Italy.
| | - Annarita Fiorillo
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy
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8
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Fagerholm SC, Guenther C, Llort Asens M, Savinko T, Uotila LM. Beta2-Integrins and Interacting Proteins in Leukocyte Trafficking, Immune Suppression, and Immunodeficiency Disease. Front Immunol 2019; 10:254. [PMID: 30837997 PMCID: PMC6389632 DOI: 10.3389/fimmu.2019.00254] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/29/2019] [Indexed: 12/21/2022] Open
Abstract
Beta2-integrins are complex leukocyte-specific adhesion molecules that are essential for leukocyte (e.g., neutrophil, lymphocyte) trafficking, as well as for other immunological processes such as neutrophil phagocytosis and ROS production, and T cell activation. Intriguingly, however, they have also been found to negatively regulate cytokine responses, maturation, and migratory responses in myeloid cells such as macrophages and dendritic cells, revealing new, and unexpected roles of these molecules in immunity. Because of their essential role in leukocyte function, a lack of expression or function of beta2-integrins causes rare immunodeficiency syndromes, Leukocyte adhesion deficiency type I, and type III (LAD-I and LAD-III). LAD-I is caused by reduced or lost expression of beta2-integrins, whilst in LAD-III, beta2-integrins are expressed but dysfunctional because a major integrin cytoplasmic regulator, kindlin-3, is mutated. Interestingly, some LAD-related phenotypes such as periodontitis have recently been shown to be due to an uncontrolled inflammatory response rather than to an uncontrolled infection, as was previously thought. This review will focus on the recent advances concerning the regulation and functions of beta2-integrins in leukocyte trafficking, immune suppression, and immune deficiency disease.
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Affiliation(s)
- Susanna C Fagerholm
- Molecular and Integrative Biosciences Research Program, Faculty of Bio- and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Carla Guenther
- Molecular and Integrative Biosciences Research Program, Faculty of Bio- and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Marc Llort Asens
- Molecular and Integrative Biosciences Research Program, Faculty of Bio- and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | | | - Liisa M Uotila
- Research Services, University of Helsinki, Helsinki, Finland
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9
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Applications of In-Cell NMR in Structural Biology and Drug Discovery. Int J Mol Sci 2019; 20:ijms20010139. [PMID: 30609728 PMCID: PMC6337603 DOI: 10.3390/ijms20010139] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/24/2018] [Accepted: 12/29/2018] [Indexed: 01/23/2023] Open
Abstract
In-cell nuclear magnetic resonance (NMR) is a method to provide the structural information of a target at an atomic level under physiological conditions and a full view of the conformational changes of a protein caused by ligand binding, post-translational modifications or protein⁻protein interactions in living cells. Previous in-cell NMR studies have focused on proteins that were overexpressed in bacterial cells and isotopically labeled proteins injected into oocytes of Xenopus laevis or delivered into human cells. Applications of in-cell NMR in probing protein modifications, conformational changes and ligand bindings have been carried out in mammalian cells by monitoring isotopically labeled proteins overexpressed in living cells. The available protocols and successful examples encourage wide applications of this technique in different fields such as drug discovery. Despite the challenges in this method, progress has been made in recent years. In this review, applications of in-cell NMR are summarized. The successful applications of this method in mammalian and bacterial cells make it feasible to play important roles in drug discovery, especially in the step of target engagement.
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10
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Thome S, Begandt D, Pick R, Salvermoser M, Walzog B. Intracellular β 2 integrin (CD11/CD18) interacting partners in neutrophil trafficking. Eur J Clin Invest 2018; 48 Suppl 2:e12966. [PMID: 29896791 DOI: 10.1111/eci.12966] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 06/10/2018] [Indexed: 12/15/2022]
Abstract
BACKGROUND Neutrophil recruitment during acute inflammation critically depends on the spatial and temporal regulation of β2 integrins (CD11/CD18). This regulation occurs by inside-out and outside-in signalling via interaction of cytoplasmic proteins with the intracellular domains of the integrin α- and β-subunits. The underlying molecular mechanisms regulating β2 integrins in neutrophils are still incompletely understood. AIM This review provides a comprehensive overview of our current knowledge on proteins interacting with the cytoplasmic tail of CD18, the conserved β-subunit of β2 integrins, their regulation and their functional importance for neutrophil trafficking during acute inflammation. RESULTS A total of 22 proteins including Talin, Kindlin 3 and Coronin 1A have been reported to interact with the CD18 cytoplasmic tail. Here, proteins binding to the cytoplasmic domain of CD18 in experiments using purified, recombinant proteins or peptides in, for example, pull-down assays, are defined as direct interactors. Proteins that have been shown to interact with the cytoplasmic domain of CD18 using whole cell lysates in, for example, pull-down experiments are claimed as interacting proteins without evidence for direct interaction. In summary, β2 integrin activation and signalling depend on a specific subset of proteins interacting with CD18 and their precise regulation. If disturbed, profound defects of neutrophil recruitment and activation become evident compromising the innate immune response. CONCLUSIONS The knowledge of proteins interacting with β2 integrins and their regulation during neutrophil trafficking does not only improve our basic understanding of innate immunity but may pave the way to novel therapeutic strategies in the treatment of inflammatory diseases.
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Affiliation(s)
- Sarah Thome
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany.,Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, LMU Munich, Planegg-Martinsried, Germany
| | - Daniela Begandt
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany.,Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, LMU Munich, Planegg-Martinsried, Germany
| | - Robert Pick
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany.,Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, LMU Munich, Planegg-Martinsried, Germany
| | - Melanie Salvermoser
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany.,Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, LMU Munich, Planegg-Martinsried, Germany
| | - Barbara Walzog
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany.,Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, LMU Munich, Planegg-Martinsried, Germany
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11
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Chatterjee D, D'Souza A, Zhang Y, Bin W, Tan SM, Bhattacharjya S. Interaction Analyses of 14-3-3ζ, Dok1, and Phosphorylated Integrin β Cytoplasmic Tails Reveal a Bi-molecular Switch in Integrin Regulation. J Mol Biol 2018; 430:4419-4430. [PMID: 30243836 DOI: 10.1016/j.jmb.2018.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 12/11/2022]
Abstract
Integrins are hetero-dimeric (α and β subunits) type I transmembrane proteins that facilitate cell adhesion and migration. The cytoplasmic tails (CTs) of integrins interact with a plethora of intra-cellular proteins that are required for integrin bidirectional signaling. In particular, the β CTs of integrins are known to recruit a variety of cytosolic proteins that often have overlapping recognition sites. However, the chronological sequence of β CTs/cytosolic proteins interactions remains to be fully characterized. Previous studies have shown that the scaffold protein 14-3-3ζ binds to phosphorylated β CTs in activated integrins, whereas interactions of Dok-1 with phosphorylated β CTs maintained integrins in the resting state. In this study, we examined the binding interactions between 14-3-3ζ, Dok1, and phosphorylated integrin β2 and β3 CTs. We show that the scaffold protein 14-3-3ζ interacts with the phosphotyrosine binding (PTB) domain of Dok1 even in the absence of the phosphorylated integrin β CTs. The interactions were mapped onto the β-sheet region of the PTB domain of Dok1. Furthermore, we provide evidence that the 14-3-3ζ/Dok1 binary complex is able to bind to their cognate phosphorylated sequence motifs in the integrin β CTs. We demonstrate that Thr phosphorylated pTTT β2 CT or pTST β3 CT can bind to 14-3-3ζ that is in complex with the Dok1 PTB domain, whereas Ser phosphorylated β2 CT or Tyr phosphorylated β3 CT interacted with Dok1 in 14-3-3ζ/Dok1 complex. Based on these data, we propose that 14-3-3ζ/Dok1 complex could serve as a molecular switch providing novel molecular insights into the regulating integrin activation.
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Affiliation(s)
- Deepak Chatterjee
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Areetha D'Souza
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Yaming Zhang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
| | - Wu Bin
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
| | - Suet-Mien Tan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore.
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12
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NMR Structure, Dynamics and Interactions of the Integrin β2 Cytoplasmic Tail with Filamin Domain IgFLNa21. Sci Rep 2018; 8:5490. [PMID: 29615775 PMCID: PMC5882645 DOI: 10.1038/s41598-018-23866-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/20/2018] [Indexed: 02/06/2023] Open
Abstract
Integrins are transmembrane proteins that mediate cell adhesion and migration. Each integrin is a heterodimer formed by an α and a β subunit. A large number of cytoplasmic proteins interact with the cytoplasmic tails (CTs) of integrins. The actin-binding cytoskeletal protein filamin A is a negative regulator of integrin activation. The IgFLNa21 domain of filamin A binds to the C-terminus of β2 CT that contains a TTT-motif. Based on x-ray crystallography, it has been reported that the integrin β2 CT forms a β strand that docks into the β strands C and D of IgFLNa21. In this study, we performed solution NMR analyses of IgFLNa21 in the presence of integrin β2 CT peptides, and hybrid IgFLNa21, a construct of covalently linked IgFLNa21 and β2 CT. The atomic resolution structure of the hybrid IgFLNa21 demonstrated conserved binding mode with β2 CT. Although, 15N relaxation, model free analyses and H-D exchange studies have uncovered important insights into the conformational dynamics and stability of β2 CT in complex with IgFLNa21. Such dynamical characteristics are likely to be necessary for the TTT-motif to serve as a phosphorylation switch that regulates filamin A binding to integrin β2 CT.
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13
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Sluchanko NN. Association of Multiple Phosphorylated Proteins with the 14-3-3 Regulatory Hubs: Problems and Perspectives. J Mol Biol 2017; 430:20-26. [PMID: 29180038 DOI: 10.1016/j.jmb.2017.11.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 01/11/2023]
Abstract
14-3-3 proteins are well-known universal regulators binding a vast number of partners by recognizing their phosphorylated motifs, typically located within the intrinsically disordered regions. The abundance of such phosphomotifs ensures the involvement of 14-3-3 proteins in sophisticated protein-protein interaction networks that govern vital cellular processes. Thousands of 14-3-3 partners have been either experimentally identified or predicted, but the spatiotemporal hierarchy of the processes based on 14-3-3 interactions is not clearly understood. This is exacerbated by the lack of available structural information on full regulatory complexes involving 14-3-3, which resist high-resolution structural studies due to the presence of intrinsically disordered regions. Although deducing three-dimensional structures is of particular urgency, structural advances are lagging behind the rate at which novel 14-3-3 partners are discovered. Here I attempted to critically review the current state of the field and in particular to dissect the unknowns, focusing on questions that could help in moving the frontiers forward.
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Affiliation(s)
- Nikolai N Sluchanko
- A.N. Bach Institute of Biochemistry, Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, 119071 Moscow, Russian Federation; Department of Biophysics, School of Biology, Moscow State University, 119991 Moscow, Russian Federation.
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14
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Sluchanko NN, Gusev NB. Moonlighting chaperone‐like activity of the universal regulatory 14‐3‐3 proteins. FEBS J 2017; 284:1279-1295. [DOI: 10.1111/febs.13986] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 11/20/2016] [Accepted: 12/06/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Nikolai N. Sluchanko
- Laboratory of Structural Biochemistry of Proteins A. N. Bach Institute of Biochemistry Federal Research Center of Biotechnology of the Russian Academy of Sciences Moscow Russia
| | - Nikolai B. Gusev
- Department of Biochemistry School of Biology Moscow State University Russia
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