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Eshaq AM, Flanagan TW, Hassan SY, Al Asheikh SA, Al-Amoudi WA, Santourlidis S, Hassan SL, Alamodi MO, Bendhack ML, Alamodi MO, Haikel Y, Megahed M, Hassan M. Non-Receptor Tyrosine Kinases: Their Structure and Mechanistic Role in Tumor Progression and Resistance. Cancers (Basel) 2024; 16:2754. [PMID: 39123481 PMCID: PMC11311543 DOI: 10.3390/cancers16152754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/30/2024] [Accepted: 07/29/2024] [Indexed: 08/12/2024] Open
Abstract
Protein tyrosine kinases (PTKs) function as key molecules in the signaling pathways in addition to their impact as a therapeutic target for the treatment of many human diseases, including cancer. PTKs are characterized by their ability to phosphorylate serine, threonine, or tyrosine residues and can thereby rapidly and reversibly alter the function of their protein substrates in the form of significant changes in protein confirmation and affinity for their interaction with protein partners to drive cellular functions under normal and pathological conditions. PTKs are classified into two groups: one of which represents tyrosine kinases, while the other one includes the members of the serine/threonine kinases. The group of tyrosine kinases is subdivided into subgroups: one of them includes the member of receptor tyrosine kinases (RTKs), while the other subgroup includes the member of non-receptor tyrosine kinases (NRTKs). Both these kinase groups function as an "on" or "off" switch in many cellular functions. NRTKs are enzymes which are overexpressed and activated in many cancer types and regulate variable cellular functions in response to extracellular signaling-dependent mechanisms. NRTK-mediated different cellular functions are regulated by kinase-dependent and kinase-independent mechanisms either in the cytoplasm or in the nucleus. Thus, targeting NRTKs is of great interest to improve the treatment strategy of different tumor types. This review deals with the structure and mechanistic role of NRTKs in tumor progression and resistance and their importance as therapeutic targets in tumor therapy.
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Affiliation(s)
- Abdulaziz M. Eshaq
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA;
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Thomas W. Flanagan
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA 70112, USA;
| | - Sofie-Yasmin Hassan
- Department of Pharmacy, Faculty of Science, Heinrich-Heine University Duesseldorf, 40225 Duesseldorf, Germany;
| | - Sara A. Al Asheikh
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Waleed A. Al-Amoudi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Simeon Santourlidis
- Institute of Cell Therapeutics and Diagnostics, University Medical Center of Duesseldorf, 40225 Duesseldorf, Germany;
| | - Sarah-Lilly Hassan
- Department of Chemistry, Faculty of Science, Heinrich-Heine University Duesseldorf, 40225 Duesseldorf, Germany;
| | - Maryam O. Alamodi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Marcelo L. Bendhack
- Department of Urology, Red Cross University Hospital, Positivo University, Rua Mauá 1111, Curitiba 80030-200, Brazil;
| | - Mohammed O. Alamodi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Youssef Haikel
- Institut National de la Santé et de la Recherche Médicale, University of Strasbourg, 67000 Strasbourg, France;
- Department of Operative Dentistry and Endodontics, Dental Faculty, 67000 Strasbourg, France
- Pôle de Médecine et Chirurgie Bucco-Dentaire, Hôpital Civil, Hôpitaux Universitaire de Strasbourg, 67000 Strasbourg, France
| | - Mossad Megahed
- Clinic of Dermatology, University Hospital of Aachen, 52074 Aachen, Germany;
| | - Mohamed Hassan
- Institut National de la Santé et de la Recherche Médicale, University of Strasbourg, 67000 Strasbourg, France;
- Department of Operative Dentistry and Endodontics, Dental Faculty, 67000 Strasbourg, France
- Research Laboratory of Surgery-Oncology, Department of Surgery, Tulane University School of Medicine, New Orleans, LA 70112, USA
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2
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Park E, Barclay WE, Barrera A, Liao TC, Salzler HR, Reddy TE, Shinohara ML, Ciofani M. Integrin α3 promotes T H17 cell polarization and extravasation during autoimmune neuroinflammation. Sci Immunol 2023; 8:eadg7597. [PMID: 37831759 PMCID: PMC10821720 DOI: 10.1126/sciimmunol.adg7597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023]
Abstract
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) caused by CNS-infiltrating leukocytes, including TH17 cells that are critical mediators of disease pathogenesis. Although targeting leukocyte trafficking is effective in treating autoimmunity, there are currently no therapeutic interventions that specifically block encephalitogenic TH17 cell migration. Here, we report integrin α3 as a TH17 cell-selective determinant of pathogenicity in experimental autoimmune encephalomyelitis. CNS-infiltrating TH17 cells express high integrin α3, and its deletion in CD4+ T cells or Il17a fate-mapped cells attenuated disease severity. Mechanistically, integrin α3 enhanced the immunological synapse formation to promote the polarization and proliferation of TH17 cells. Moreover, the transmigration of TH17 cells into the CNS was dependent on integrin α3, and integrin α3 deficiency enhanced the retention of CD4+ T cells in the perivascular space of the blood-brain barrier. Integrin α3-dependent interactions continuously maintain TH17 cell identity and effector function. The requirement of integrin α3 in TH17 cell pathogenicity suggests integrin α3 as a therapeutic target for MS treatment.
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Affiliation(s)
- Eunchong Park
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC, USA
- Center for Advanced Genomic Technologies, Duke University, Durham, NC, USA
| | - William E. Barclay
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC, USA
| | - Alejandro Barrera
- Center for Advanced Genomic Technologies, Duke University, Durham, NC, USA
- Department of Biostatistics and Bioinformatics, Duke University Medical School, Durham, NC, USA
| | - Tzu-Chieh Liao
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC, USA
- Center for Advanced Genomic Technologies, Duke University, Durham, NC, USA
| | - Harmony R. Salzler
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC, USA
| | - Timothy E. Reddy
- Center for Advanced Genomic Technologies, Duke University, Durham, NC, USA
- Department of Biostatistics and Bioinformatics, Duke University Medical School, Durham, NC, USA
| | - Mari L. Shinohara
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Maria Ciofani
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC, USA
- Center for Advanced Genomic Technologies, Duke University, Durham, NC, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
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3
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Molecular basis for integrin adhesion receptor binding to p21-activated kinase 4 (PAK4). Commun Biol 2022; 5:1257. [PMID: 36385162 PMCID: PMC9669019 DOI: 10.1038/s42003-022-04157-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 10/24/2022] [Indexed: 11/18/2022] Open
Abstract
AbstractIntegrin adhesion receptors provide links between extracellular ligands and cytoplasmic signaling. Multiple kinases have been found to directly engage with integrin β tails, but the molecular basis for these interactions remain unknown. Here, we assess the interaction between the kinase domain of p21-activated kinase 4 (PAK4) and the cytoplasmic tail of integrin β5. We determine three crystal structures of PAK4-β5 integrin complexes and identify the PAK-binding site. This is a region in the membrane-proximal half of the β5 tail and confirmed by site-directed mutagenesis. The β5 tail engages the kinase substrate-binding groove and positions the non-phosphorylatable integrin residue Glu767 at the phosphoacceptor site. Consistent with this, integrin β5 is poorly phosphorylated by PAK4, and in keeping with its ability to occlude the substrate-binding site, weakly inhibits kinase activity. These findings demonstrate the molecular basis for β5 integrin-PAK4 interactions but suggest modifications in understanding the potential cellular role of this interaction.
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4
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Shahi A, Kahle J, Hopkins C, Diakonova M. The SH2 domain and kinase activity of JAK2 target JAK2 to centrosome and regulate cell growth and centrosome amplification. PLoS One 2022; 17:e0261098. [PMID: 35089929 PMCID: PMC8797172 DOI: 10.1371/journal.pone.0261098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 11/23/2021] [Indexed: 12/13/2022] Open
Abstract
JAK2 is cytokine-activated non-receptor tyrosine kinase. Although JAK2 is mainly localized at the plasma membrane, it is also present on the centrosome. In this study, we demonstrated that JAK2 localization to the centrosome depends on the SH2 domain and intact kinase activity. We created JAK2 mutants deficient in centrosomal localization ΔSH2, K882E and (ΔSH2, K882E). We showed that JAK2 WT clone strongly enhances cell proliferation as compared to control cells while JAK2 clones ΔSH2, K882E and (ΔSH2, K882E) proliferate slower than JAK2 WT cells. These mutant clones also progress much slower through the cell cycle as compared to JAK2 WT clone and the enhanced proliferation of JAK2 WT cells is accompanied by increased S -> G2 progression. Both the SH2 domain and the kinase activity of JAK2 play a role in prolactin-dependent activation of JAK2 substrate STAT5. We showed that JAK2 is an important regulator of centrosome function as the SH2 domain of JAK2 regulates centrosome amplification. The cells overexpressing ΔSH2 and (ΔSH2, K-E) JAK2 have almost three-fold the amplified centrosomes of WT cells. In contrast, the kinase activity of JAK2 is dispensable for centrosome amplification. Our observations provide novel insight into the role of SH2 domain and kinase activity of JAK2 in centrosome localization of JAK2 and in the regulation of cell growth and centrosome biogenesis.
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Affiliation(s)
- Aashirwad Shahi
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States of America
| | - Jacob Kahle
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States of America
| | - Chandler Hopkins
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States of America
| | - Maria Diakonova
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States of America
- * E-mail:
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5
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Bouti P, Webbers SDS, Fagerholm SC, Alon R, Moser M, Matlung HL, Kuijpers TW. β2 Integrin Signaling Cascade in Neutrophils: More Than a Single Function. Front Immunol 2021; 11:619925. [PMID: 33679708 PMCID: PMC7930317 DOI: 10.3389/fimmu.2020.619925] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/31/2020] [Indexed: 12/13/2022] Open
Abstract
Neutrophils are the most prevalent leukocytes in the human body. They have a pivotal role in the innate immune response against invading bacterial and fungal pathogens, while recent emerging evidence also demonstrates their role in cancer progression and anti-tumor responses. The efficient execution of many neutrophil effector responses requires the presence of β2 integrins, in particular CD11a/CD18 or CD11b/CD18 heterodimers. Although extensively studied at the molecular level, the exact signaling cascades downstream of β2 integrins still remain to be fully elucidated. In this review, we focus mainly on inside-out and outside-in signaling of these two β2 integrin members expressed on neutrophils and describe differences between various neutrophil stimuli with respect to integrin activation, integrin ligand binding, and the pertinent differences between mouse and human studies. Last, we discuss how integrin signaling studies could be used to explore the therapeutic potential of targeting β2 integrins and the intracellular signaling cascade in neutrophils in several, among other, inflammatory conditions in which neutrophil activity should be dampened to mitigate disease.
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Affiliation(s)
- Panagiota Bouti
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Steven D S Webbers
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Immunology, Rheumatology and Infectious Disease, Amsterdam University Medical Center (AUMC), Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
| | - Susanna C Fagerholm
- Research Program of Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ronen Alon
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Markus Moser
- Institute of Experimental Hematology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Hanke L Matlung
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Taco W Kuijpers
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Immunology, Rheumatology and Infectious Disease, Amsterdam University Medical Center (AUMC), Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
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6
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Bakthavatsalam D, Craft JW, Kazansky A, Nguyen N, Bae G, Caivano AR, Gundlach CW, Aslam A, Ali S, Gupta S, Lin SY, Parthiban HD, Vanderslice P, Stephan CC, Woodside DG. Identification of Inhibitors of Integrin Cytoplasmic Domain Interactions With Syk. Front Immunol 2021; 11:575085. [PMID: 33488575 PMCID: PMC7819857 DOI: 10.3389/fimmu.2020.575085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/20/2020] [Indexed: 11/13/2022] Open
Abstract
Leukocyte inflammatory responses require integrin cell-adhesion molecule signaling through spleen tyrosine kinase (Syk), a non-receptor kinase that binds directly to integrin β-chain cytoplasmic domains. Here, we developed a high-throughput screen to identify small molecule inhibitors of the Syk-integrin cytoplasmic domain interactions. Screening small molecule compound libraries identified the β-lactam antibiotics cefsulodin and ceftazidime, which inhibited integrin β-subunit cytoplasmic domain binding to the tandem SH2 domains of Syk (IC50 range, 1.02-4.9 µM). Modeling suggested antagonist binding to Syk outside the pITAM binding site. Ceftazidime inhibited integrin signaling via Syk, including inhibition of adhesion-dependent upregulation of interleukin-1β and monocyte chemoattractant protein-1, but did not inhibit ITAM-dependent phosphorylation of Syk mediated by FcγRI signaling. Our results demonstrate a novel means to target Syk independent of its kinase and pITAM binding sites such that integrin signaling via this kinase is abrogated but ITAM-dependent signaling remains intact. As integrin signaling through Syk is essential for leukocyte activation, this may represent a novel approach to target inflammation.
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Affiliation(s)
| | - John W. Craft
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
- Department of Biology and Chemistry, University of Houston, Houston, TX, United States
| | - Anna Kazansky
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
| | - Nghi Nguyen
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| | - Goeun Bae
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| | - Amy R. Caivano
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
| | - C. William Gundlach
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
| | - Asra Aslam
- Department of Biology and Chemistry, University of Houston, Houston, TX, United States
| | - Safa Ali
- Department of Biology and Chemistry, University of Houston, Houston, TX, United States
| | - Shashikant Gupta
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
| | - Sophie Y. Lin
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
| | - Hema D. Parthiban
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
| | - Peter Vanderslice
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
| | - Clifford C. Stephan
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| | - Darren G. Woodside
- Molecular Cardiology Research Laboratories, Texas Heart Institute, Houston, TX, United States
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7
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Single-Protein Tracking to Study Protein Interactions During Integrin-Based Migration. Methods Mol Biol 2021; 2217:85-113. [PMID: 33215379 DOI: 10.1007/978-1-0716-0962-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Cell migration is a complex biophysical process which involves the coordination of molecular assemblies including integrin-dependent adhesions, signaling networks and force-generating cytoskeletal structures incorporating both actin polymerization and myosin activity. During the last decades, proteomic studies have generated impressive protein-protein interaction maps, although the subcellular location, duration, strength, sequence, and nature of these interactions are still concealed. In this chapter we describe how recent developments in superresolution microscopy (SRM) and single-protein tracking (SPT) start to unravel protein interactions and actions in subcellular molecular assemblies driving cell migration.
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8
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Cheng H, Schwell V, Curtis BR, Fazlieva R, Roder H, Campbell KS. Conformational Changes in the Cytoplasmic Region of KIR3DL1 upon Interaction with SHP-2. Structure 2019; 27:639-650.e2. [PMID: 30773397 DOI: 10.1016/j.str.2019.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/07/2018] [Accepted: 01/18/2019] [Indexed: 12/29/2022]
Abstract
KIR3DL1 is an inhibitory killer cell immunoglobulin-like receptor (KIR) that negatively regulates natural killer cell cytotoxicity. The KIR3DL1 cytoplasmic region (3DL1-cyto) is disordered and can be dissected into three segments: (I) H340-V351; (II) M352-D371; and (III) P372-P423. NMR studies indicate that segment II can dynamically adopt a loop-like conformation, and segments I and III can form dynamic helices that may mediate binding to membranes, particularly in the region around the N-terminal (N) immunoreceptor tyrosine-based inhibitory motif (ITIM), consistent with its role in signaling. Furthermore, individual SH2 domains of SHP-2 strongly engage with the unphosphorylated N-ITIM of 3DL1-cyto, while binding of the tandem SHP-2 SH2 domains to the bis-phosphorylated ITIMs results in more extensive conformational changes in segments I and III. The findings enhance our understanding of KIR function and how ITIMs in a target receptor operate in concert to engage the tandem SH2 domains of SHP-2.
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Affiliation(s)
- Hong Cheng
- Institute for Cancer Research, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA.
| | - Vered Schwell
- Institute for Cancer Research, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
| | - Brett R Curtis
- Institute for Cancer Research, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
| | - Ruzaliya Fazlieva
- Institute for Cancer Research, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
| | - Heinrich Roder
- Institute for Cancer Research, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
| | - Kerry S Campbell
- Institute for Cancer Research, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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9
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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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10
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Antenucci L, Hytönen VP, Ylänne J. Phosphorylated immunoreceptor tyrosine-based activation motifs and integrin cytoplasmic domains activate spleen tyrosine kinase via distinct mechanisms. J Biol Chem 2018; 293:4591-4602. [PMID: 29440271 DOI: 10.1074/jbc.ra117.000660] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 02/07/2018] [Indexed: 11/06/2022] Open
Abstract
Spleen tyrosine kinase (Syk) is involved in cellular adhesion and also in the activation and development of hematopoietic cells. Syk activation induced by genomic rearrangement has been linked to certain T-cell lymphomas, and Syk inhibitors have been shown to prolong survival of patients with B-cell lineage malignancies. Syk is activated either by its interaction with a double-phosphorylated immunoreceptor tyrosine-based activation motif (pITAM), which induces rearrangements in the Syk structure, or by the phosphorylation of specific tyrosine residues. In addition to its immunoreceptor function, Syk is activated downstream of integrin pathways, and integrins bind to the same region in Syk as does pITAM. However, it is unknown whether integrins and pITAM use the same mechanism to activate Syk. Here, using purified Syk protein and fluorescence-based enzyme assay we investigated whether interaction of the integrin β3 cytoplasmic domain with the Syk regulatory domain causes changes in Syk activity similar to those induced by pITAM peptides. We observed no direct Syk activation by soluble integrin peptide, and integrin did not compete with pITAM-induced activation even though at high concentrations, the integrin cytoplasmic domain peptide competed with Syk's substrate. However, clustered integrin peptides induced Syk activation, presumably via a transphosphorylation mechanism. Moreover, the clustered integrins also activated a Syk variant in which tyrosines were replaced with phenylalanine (Y348F/Y352F), indicating that clustered integrin-induced Syk activation involved other phosphorylation sites. In conclusion, integrin cytoplasmic domains do not directly induce Syk conformational changes and do not activate Syk via the same mechanism as pITAM.
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Affiliation(s)
- Lina Antenucci
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Survontie 9 C, 40014 Jyväskylä, Finland.
| | - Vesa P Hytönen
- Faculty of Medicine and Life Sciences and BioMediTech, University of Tampere, and Fimlab Laboratories, Tampere 33014, Finland
| | - Jari Ylänne
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Survontie 9 C, 40014 Jyväskylä, Finland
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11
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Wu CY, Tsai YY, Chen SY, Lin YP, Shin JW, Wu CC, Yang BC. Interaction of Zap70 and CXCR4 receptor at lamellipodia that determines the directionality during Jurkat T cells chemotaxis. Mol Immunol 2017; 90:245-254. [DOI: 10.1016/j.molimm.2017.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/21/2017] [Accepted: 08/13/2017] [Indexed: 10/19/2022]
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12
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Shapiro LP, Parsons RG, Koleske AJ, Gourley SL. Differential expression of cytoskeletal regulatory factors in the adolescent prefrontal cortex: Implications for cortical development. J Neurosci Res 2017; 95:1123-1143. [PMID: 27735056 PMCID: PMC5352542 DOI: 10.1002/jnr.23960] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 09/04/2016] [Accepted: 09/12/2016] [Indexed: 12/27/2022]
Abstract
The prevalence of depression, anxiety, schizophrenia, and drug and alcohol use disorders peaks during adolescence. Further, up to 50% of "adult" mental health disorders emerge in adolescence. During adolescence, the prefrontal cortex (PFC) undergoes dramatic structural reorganization, in which dendritic spines and synapses are refined, pruned, and stabilized. Understanding the molecular mechanisms that underlie these processes should help to identify factors that influence the development of psychiatric illness. Here we briefly discuss the anatomical connections of the medial and orbital prefrontal cortex (mPFC and OFC, respectively). We then present original findings suggesting that dendritic spines on deep-layer excitatory neurons in the mouse mPFC and OFC prune at different adolescent ages, with later pruning in the OFC. In parallel, we used Western blotting to define levels of several cytoskeletal regulatory proteins during early, mid-, and late adolescence, focusing on tropomyosin-related kinase receptor B (TrkB) and β1-integrin-containing receptors and select signaling partners. We identified regional differences in the levels of several proteins in early and midadolescence that then converged in early adulthood. We also observed age-related differences in TrkB levels, both full-length and truncated isoforms, Rho-kinase 2, and synaptophysin in both PFC subregions. Finally, we identified changes in protein levels in the dorsal and ventral hippocampus that were distinct from those in the PFC. We conclude with a general review of the manner in which TrkB- and β1-integrin-mediated signaling influences neuronal structure in the postnatal brain. Elucidating the role of cytoskeletal regulatory factors throughout adolescence may identify critical mechanisms of PFC development. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Lauren P Shapiro
- Molecular and Systems Pharmacology, Emory University, Atlanta, Georgia
- Departments of Pediatrics and Psychiatry and Behavioral Sciences, Emory University School of Medicine, and Yerkes National Primate Research Center, Emory University, Atlanta, Georgia
| | - Ryan G Parsons
- Department of Psychology and Neuroscience Institute, Graduate Program in Integrative Neuroscience, Program in Neuroscience, Stony Brook University, Stony Brook, New York
| | - Anthony J Koleske
- Department of Molecular Biophysics and Biochemistry, Department of Neurobiology, Interdepartmental Neuroscience Program, Yale University, New Haven, Connecticut
| | - Shannon L Gourley
- Departments of Pediatrics and Psychiatry and Behavioral Sciences, Emory University School of Medicine, and Yerkes National Primate Research Center, Emory University, Atlanta, Georgia
- Graduate Program in Neuroscience, Emory University, Atlanta, Georgia
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13
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Hahnel S, Parker-Manuel R, Dissous C, Cailliau K, Grevelding CG. First characterization of SmOPG1, a novel protein involved in gonad-associated processes in Schistosoma mansoni. Mol Biochem Parasitol 2017; 213:22-25. [DOI: 10.1016/j.molbiopara.2017.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/27/2017] [Accepted: 01/28/2017] [Indexed: 11/24/2022]
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14
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Zhou Y, Abraham S, Renna S, Edelstein LC, Dangelmaier CA, Tsygankov AY, Kunapuli SP, Bray PF, McKenzie SE. TULA-2 (T-Cell Ubiquitin Ligand-2) Inhibits the Platelet Fc Receptor for IgG IIA (FcγRIIA) Signaling Pathway and Heparin-Induced Thrombocytopenia in Mice. Arterioscler Thromb Vasc Biol 2016; 36:2315-2323. [PMID: 27765766 DOI: 10.1161/atvbaha.116.307979] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 10/04/2016] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The objective of this study is to investigate the role of T-cell ubiquitin ligand-2 (TULA-2) in the platelet Fc receptor for IgG IIA (FcγRIIA) pathway and in the pathogenesis of heparin-induced thrombocytopenia (HIT). APPROACH AND RESULTS HIT is a life-threatening thrombotic disease in which IgG antibodies against the heparin-platelet factor 4 complex activate platelets via FcγRIIA. We reported previously differential expression of TULA-2 in human population was linked to FcγRIIA responsiveness. In this study, we investigated the role of TULA-2, a protein phosphatase, in the FcγRIIA pathway and HIT pathogenesis by crossing TULA-2-/- mice with transgenic FcγRIIA +/+ mice. Ablation of TULA-2 resulted in hyperphosphorylation of spleen tyrosine kinase, linker for the activation of T cells, and phospholipase Cγ2 in platelets via FcγRIIA activation. Platelet integrin activation, granule secretion, phosphatidylserine exposure, and aggregation were also enhanced in TULA-2-/- murine platelets. Compared with wild-type mice, TULA-2-/- mice showed aggravated antibody-mediated thrombocytopenia, augmented thrombin generation, and shortened tail bleeding time. In contrast, there was no significant difference between TULA-2-/- and TULA-2+/+ platelets in platelet spreading and clot retraction. Of note, heterozygous TULA-2+/- mice, whose platelets contained 50% as much protein as the TULA-2+/+ platelets, showed significantly increased platelet reactivity and more severe thrombocytopenia in vivo compared with TULA-2+/+ mice. CONCLUSIONS Together, the data demonstrate that not only the absence of TULA-2 but also the relative level of TULA-2 expression modulates FcγRIIA-mediated platelet reactivity and HIT in vivo. TULA-2 expression could be a valuable marker for HIT and inhibiting TULA-2 may serve as a potential therapy to reverse the bleeding adverse effect of anticoagulants.
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Affiliation(s)
- Yuhang Zhou
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Shaji Abraham
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Stephanie Renna
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Leonard C Edelstein
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Carol A Dangelmaier
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Alexander Y Tsygankov
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Satya P Kunapuli
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Paul F Bray
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Steven E McKenzie
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.).
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15
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Rakshambikai R, Manoharan M, Gnanavel M, Srinivasan N. Typical and atypical domain combinations in human protein kinases: functions, disease causing mutations and conservation in other primates. RSC Adv 2015. [DOI: 10.1039/c4ra11685b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A twist in the evolution of human kinases resulting in kinases with hybrid and rogue properties.
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Affiliation(s)
| | - Malini Manoharan
- Molecular Biophysics Unit
- Indian Institute of Science
- Bangalore 560012
- India
| | - Mutharasu Gnanavel
- Molecular Biophysics Unit
- Indian Institute of Science
- Bangalore 560012
- India
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16
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The N-terminal SH2 domain of Syk is required for (hem)ITAM, but not integrin, signaling in mouse platelets. Blood 2014; 125:144-54. [PMID: 25352128 DOI: 10.1182/blood-2014-05-579375] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have used a novel knockin mouse to investigate the effect of disruption of phosphotyrosine binding of the N-terminal SH2 domain of Syk on platelet activation by GPVI, CLEC-2, and integrin αIIbβ3. The Syk(R41Afl/fl) mouse was crossed to a PF4-Cre(+) mouse to induce expression of the Syk mutant in the megakaryocyte/platelet lineage. Syk(R41Afl/fl;PF4-Cre) mice are born at approximately 50% of the expected frequency and have a similar phenotype to Syk(fl/fl;PF4-Cre) mice, including blood-lymphatic mixing and chyloascites. Anastomosis of the venous and lymphatic vasculatures can be seen in the mesenteric circulation accounting for rapid and continuous mixing of the 2 vasculatures. Platelet activation by CLEC-2 and GPVI is abolished in Syk(R41Afl/fl;PF4-Cre) platelets. Syk phosphorylation on Tyr519/20 is blocked in CLEC-2-stimulated platelets, suggesting a model in which binding of Syk via its N-terminal SH2 domain regulates autophosphorylation. In contrast, outside-in signaling by integrin αIIbβ3 is not altered, but it is inhibited in the presence of inhibitors of Src and Syk tyrosine kinases. These results demonstrate that αIIbβ3 regulates Syk through an ITAM-independent pathway in mice and provide novel insight into the course of events underlying Syk activation and hemITAM phosphorylation by CLEC-2.
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17
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Functional roles of Syk in macrophage-mediated inflammatory responses. Mediators Inflamm 2014; 2014:270302. [PMID: 25045209 PMCID: PMC4090447 DOI: 10.1155/2014/270302] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 05/27/2014] [Indexed: 01/09/2023] Open
Abstract
Inflammation is a series of complex biological responses to protect the host from pathogen invasion. Chronic inflammation is considered a major cause of diseases, such as various types of inflammatory/autoimmune diseases and cancers. Spleen tyrosine kinase (Syk) was initially found to be highly expressed in hematopoietic cells and has been known to play crucial roles in adaptive immune responses. However, recent studies have reported that Syk is also involved in other biological functions, especially in innate immune responses. Although Syk has been extensively studied in adaptive immune responses, numerous studies have recently presented evidence that Syk has critical functions in macrophage-mediated inflammatory responses and is closely related to innate immune response. This review describes the characteristics of Syk-mediated signaling pathways, summarizes the recent findings supporting the crucial roles of Syk in macrophage-mediated inflammatory responses and diseases, and discusses Syk-targeted drug development for the therapy of inflammatory diseases.
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18
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Abstract
Integrins are heterodimeric cell surface adhesion receptors essential for multicellular life. They connect cells to the extracellular environment and transduce chemical and mechanical signals to and from the cell. Intracellular proteins that bind the integrin cytoplasmic tail regulate integrin engagement of extracellular ligands as well as integrin localization and trafficking. Cytoplasmic integrin-binding proteins also function downstream of integrins, mediating links to the cytoskeleton and to signaling cascades that impact cell motility, growth, and survival. Here, we review key integrin-interacting proteins and their roles in regulating integrin activity, localization, and signaling.
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Affiliation(s)
- Elizabeth M Morse
- Department of Cell Biology and ‡Department of Pharmacology, Yale University School of Medicine , 333 Cedar Street, New Haven, Connecticut 06520, United States
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19
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Oxidized low-density lipoproteins induce rapid platelet activation and shape change through tyrosine kinase and Rho kinase-signaling pathways. Blood 2013; 122:580-9. [PMID: 23699602 DOI: 10.1182/blood-2013-04-491688] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Oxidized low-density lipoproteins (oxLDL) generated in the hyperlipidemic state may contribute to unregulated platelet activation during thrombosis. Although the ability of oxLDL to activate platelets is established, the underlying signaling mechanisms remain obscure. We show that oxLDL stimulate platelet activation through phosphorylation of the regulatory light chains of the contractile protein myosin IIa (MLC). oxLDL, but not native LDL, induced shape change, spreading, and phosphorylation of MLC (serine 19) through a pathway that was ablated under conditions that blocked CD36 ligation or inhibited Src kinases, suggesting a tyrosine kinase-dependent mechanism. Consistent with this, oxLDL induced tyrosine phosphorylation of a number of proteins including Syk and phospholipase C γ2. Inhibition of Syk, Ca(2+) mobilization, and MLC kinase (MLCK) only partially inhibited MLC phosphorylation, suggesting the presence of a second pathway. oxLDL activated RhoA and RhoA kinase (ROCK) to induce inhibitory phosphorylation of MLC phosphatase (MLCP). Moreover, inhibition of Src kinases prevented the activation of RhoA and ROCK, indicating that oxLDL regulates contractile signaling through a tyrosine kinase-dependent pathway that induces MLC phosphorylation through the dual activation of MLCK and inhibition of MLCP. These data reveal new signaling events downstream of CD36 that are critical in promoting platelet aggregation by oxLDL.
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20
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CBAP functions as a novel component in chemokine-induced ZAP70-mediated T-cell adhesion and migration. PLoS One 2013; 8:e61761. [PMID: 23620790 PMCID: PMC3631140 DOI: 10.1371/journal.pone.0061761] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 03/11/2013] [Indexed: 01/22/2023] Open
Abstract
Activated chemokine receptor initiates inside-out signaling to transiently trigger activation of integrins, a process involving multiple components that have not been fully characterized. Here we report that GM-CSF/IL-3/IL-5 receptor common beta-chain-associated protein (CBAP) is required to optimize this inside-out signaling and activation of integrins. First, knockdown of CBAP expression in human Jurkat T cells caused attenuated CXC chemokine ligand-12 (CXCL12)-induced cell migration and integrin α4β1- and αLβ2-mediated cell adhesion in vitro, which could be rescued sufficiently upon expression of murine CBAP proteins. Freshly isolated CBAP-deficient primary T cells also exhibited diminution of chemotaxis toward CC chemokine ligand-21 (CCL21) and CXCL12, and these chemokines-induced T-cell adhesions in vitro. Adoptive transfer of isolated naive T cells demonstrated that CBAP deficiency significantly reduced lymph node homing ability in vivo. Finally, migration of T cell-receptor-activated T cells induced by inflammatory chemokines was also attenuated in CBAP-deficient cells. Further analyses revealed that CBAP constitutively associated with both integrin β1 and ZAP70 and that CBAP is required for chemokine-induced initial binding of the talin-Vav1 complex to integrin β1 and to facilitate subsequent ZAP70-mediated dissociation of the talin-Vav1 complex and Vav1 phosphorylation. Within such an integrin signaling complex, CBAP likely functions as an adaptor and ultimately leads to activation of both integrin α4β1 and Rac1. Taken together, our data suggest that CBAP indeed can function as a novel signaling component within the ZAP70/Vav1/talin complex and plays an important role in regulating chemokine-promoted T-cell trafficking.
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21
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Miller YI, Choi SH, Wiesner P, Bae YS. The SYK side of TLR4: signalling mechanisms in response to LPS and minimally oxidized LDL. Br J Pharmacol 2013; 167:990-9. [PMID: 22776094 DOI: 10.1111/j.1476-5381.2012.02097.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Spleen tyrosine kinase (SYK) is the best known for its involvement in immune receptor signalling, mediated by binding of SYK tandem Src-homology 2 domains to tandem phosphotyrosine in immunoreceptor tyrosine-based activation motifs (ITAMs). ITAM adaptors or ITAM-containing receptor tails mediate signalling from B- and T-cell receptors, Fc receptors and many C-type lectins, including dectin-1. Recent data point to constitutive binding of SYK to the cytoplasmic domain of toll-like receptor-4 (TLR4). This SYK-TLR4 binding increases upon TLR4 dimerization and phosphorylation, and SYK plays a prominent role in TLR4 signalling in response to LPS in neutrophils and monocytes. SYK also plays an important role in TLR4-mediated macrophage responses to minimally oxidized low-density lipoprotein (mmLDL), which is a form of oxidized LDL relevant to development of human atherosclerosis. Interestingly, mmLDL-induced effects in macrophages, which occur via TLR4, are predominantly MyD88 independent. This unmasks the role of the SYK branch of TLR4 signalling, which mediates modest cytokine release via activation of AP-1 transcription and robust reactive oxygen species generation and cytoskeletal rearrangements. The latter results in extensive membrane ruffling and macropinocytosis, leading to lipoprotein uptake and foam cell formation, a hallmark of atherosclerotic lesions. Because inhibitors of SYK activity, such as fostamatinib, are in advanced clinical trials for rheumatoid arthritis and other autoimmune diseases, understanding the role of SYK in signalling via TLR4 is of immediate importance. This signalling pathway seems to be particularly important in TLR4 activation by host-derived, damage-associated molecular pattern ligands, such as mmLDL, relevant to development of atherosclerosis and other chronic inflammatory diseases.
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Affiliation(s)
- Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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22
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Discovery of platyhelminth-specific α/β-integrin families and evidence for their role in reproduction in Schistosoma mansoni. PLoS One 2012; 7:e52519. [PMID: 23300694 PMCID: PMC3531407 DOI: 10.1371/journal.pone.0052519] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/15/2012] [Indexed: 12/17/2022] Open
Abstract
In all metazoa, the response of cells to molecular stimuli from their environment represents a fundamental principle of regulatory processes controlling cell growth and differentiation. Among the membrane-linked receptors mediating extracellular communication processes are integrin receptors. Besides managing adhesion to the extracellular matrix or to other cells, they arrange information flow into the cells by activating intracellular signaling pathways often acting synergistically through cooperation with growth factor receptors. Although a wealth of information exists on integrins in different model organisms, there is a big gap of knowledge for platyhelminths. Here we report on the in silico detection and reconstruction of α and β integrins from free-living and parasitic platyhelminths, which according to structural and phylogenetic analyses form specific clades separate from each other and from further metazoan integrins. As representative orthologs of parasitic platyhelminths we have cloned one beta-integrin (Smβ-Int1) and four alpha-integrins (Smα-Int1 - Smα-Int4) from Schistosoma mansoni; they were characterized by molecular and biochemical analyses. Evidence is provided that Smβ-Int1 interacts and co-localizes in the reproductive organs with known schistosome cellular tyrosine kinases (CTKs), of which the Syk kinase SmTK4 appeared to be the strongest interaction partner as shown by yeast two-hybrid analyses and coimmunoprecipitation experiments. By a novel RNAi approach with adult schistosomes in vitro we demonstrate for the first time multinucleated oocytes in treated females, indicating a decisive role Smβ-Int1 during oogenesis as phenotypically analyzed by confocal laser scanning microscopy (CLSM). Our findings provide a first comprehensive overview about platyhelminth integrins, of which the parasite group exhibits unique features allowing a clear distinction from the free-living groups. Furthermore, we shed first lights on the functions of integrins in a trematode model parasite, revealing the complexity of molecular processes involved in its reproductive biology, which may be representative for other platyhelminths.
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23
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Cooperative integrin/ITAM signaling in platelets enhances thrombus formation in vitro and in vivo. Blood 2012; 121:1858-67. [PMID: 23264598 DOI: 10.1182/blood-2012-07-443325] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The integrin family is composed of a series of 24 αβ heterodimer transmembrane adhesion receptors that mediate cell-cell and cell-extracellular matrix interactions. Adaptor molecules bearing immunoreceptor tyrosine-based activation motifs (ITAMs) have recently been shown to cooperate with specific integrins to increase the efficiency of transmitting ligand-binding-induced signals into cells. In human platelets, Fc receptor γ-chain IIa (FcγRIIa) has been identified as an ITAM-bearing transmembrane receptor responsible for mediating "outside-in" signaling through αIIbβ3, the major adhesion receptor on the platelet surface. To explore the importance of FcγRIIa in thrombosis and hemostasis, we subjected FcγRIIa-negative and FcγRIIa-positive murine platelets to a number of well-accepted models of platelet function. Compared with their FcγRIIa-negative counterparts, FcγRIIa-positive platelets exhibited increased tyrosine phosphorylation of Syk and phospholipase Cγ2 and increased spreading upon interaction with immobilized fibrinogen, retracted a fibrin clot faster, and showed markedly enhanced thrombus formation when perfused over a collagen-coated flow chamber under conditions of arterial and venous shear. They also displayed increased thrombus formation and fibrin deposition in in vivo models of vascular injury. Taken together, these data establish FcγRIIa as a physiologically important functional conduit for αIIbβ3-mediated outside-in signaling, and suggest that modulating the activity of this novel integrin/ITAM pair might be effective in controlling thrombosis.
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24
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Shammas S, Rogers J, Hill S, Clarke J. Slow, reversible, coupled folding and binding of the spectrin tetramerization domain. Biophys J 2012; 103:2203-14. [PMID: 23200054 PMCID: PMC3512043 DOI: 10.1016/j.bpj.2012.10.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/02/2012] [Accepted: 10/10/2012] [Indexed: 11/16/2022] Open
Abstract
Many intrinsically disordered proteins (IDPs) are significantly unstructured under physiological conditions. A number of these IDPs have been shown to undergo coupled folding and binding reactions whereby they can gain structure upon association with an appropriate partner protein. In general, these systems display weaker binding affinities than do systems with association between completely structured domains, with micromolar K(d) values appearing typical. One such system is the association between α- and β-spectrin, where two partially structured, incomplete domains associate to form a fully structured, three-helix bundle, the spectrin tetramerization domain. Here, we use this model system to demonstrate a method for fitting association and dissociation kinetic traces where, using typical biophysical concentrations, the association reactions are expected to be highly reversible. We elucidate the unusually slow, two-state kinetics of spectrin assembly in solution. The advantages of studying kinetics in this regime include the potential for gaining equilibrium constants as well as rate constants, and for performing experiments with low protein concentrations. We suggest that this approach would be particularly appropriate for high-throughput mutational analysis of two-state reversible binding processes.
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Affiliation(s)
| | | | | | - J. Clarke
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
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25
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The leucocyte β2 (CD18) integrins: the structure, functional regulation and signalling properties. Biosci Rep 2012; 32:241-69. [PMID: 22458844 DOI: 10.1042/bsr20110101] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Leucocytes are highly motile cells. Their ability to migrate into tissues and organs is dependent on cell adhesion molecules. The integrins are a family of heterodimeric transmembrane cell adhesion molecules that are also signalling receptors. They are involved in many biological processes, including the development of metazoans, immunity, haemostasis, wound healing and cell survival, proliferation and differentiation. The leucocyte-restricted β2 integrins comprise four members, namely αLβ2, αMβ2, αXβ2 and αDβ2, which are required for a functional immune system. In this paper, the structure, functional regulation and signalling properties of these integrins are reviewed.
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26
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Choi SH, Wiesner P, Almazan F, Kim J, Miller YI. Spleen tyrosine kinase regulates AP-1 dependent transcriptional response to minimally oxidized LDL. PLoS One 2012; 7:e32378. [PMID: 22384232 PMCID: PMC3284564 DOI: 10.1371/journal.pone.0032378] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 01/28/2012] [Indexed: 12/16/2022] Open
Abstract
Oxidative modification of low-density lipoprotein (LDL) turns it into an endogenous ligand recognized by pattern-recognition receptors. We have demonstrated that minimally oxidized LDL (mmLDL) binds to CD14 and mediates TLR4/MD-2-dependent responses in macrophages, many of which are MyD88-independent. We have also demonstrated that the mmLDL activation leads to recruitment of spleen tyrosine kinase (Syk) to TLR4 and TLR4 and Syk phosphorylation. In this study, we produced a macrophage-specific Syk knockout mouse and used primary Syk(-/-) macrophages in our studies. We demonstrated that Syk mediated phosphorylation of ERK1/2 and JNK, which in turn phosphorylated c-Fos and c-Jun, respectively, as assessed by an in vitro kinase assay. c-Jun phosphorylation was also mediated by IKKε. c-Jun and c-Fos bound to consensus DNA sites and thereby completed an AP-1 transcriptional complex and induced expression of CXCL2 and IL-6. These results suggest that Syk plays a key role in TLR4-mediated macrophage responses to host-generated ligands, like mmLDL, with subsequent activation of an AP-1 transcription program.
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Affiliation(s)
| | | | | | | | - Yury I. Miller
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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27
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Wang W, Jiang Y, Wang C, Luo BH. Effects of the Association between the α-Subunit Thigh and the β-Subunit EGF2 Domains on Integrin Activation and Signaling. Biochemistry 2011; 50:9264-72. [DOI: 10.1021/bi200744g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Wei Wang
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Yan Jiang
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Chen Wang
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Bing-Hao Luo
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
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28
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March ME, Long EO. β2 integrin induces TCRζ-Syk-phospholipase C-γ phosphorylation and paxillin-dependent granule polarization in human NK cells. THE JOURNAL OF IMMUNOLOGY 2011; 186:2998-3005. [PMID: 21270398 DOI: 10.4049/jimmunol.1002438] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cytotoxic lymphocytes kill target cells through polarized release of the content of lytic granules at the immunological synapse. In human NK cells, signals for granule polarization and for degranulation can be uncoupled: Binding of β(2) integrin LFA-1 to ICAM is sufficient to induce polarization but not degranulation, whereas CD16 binding to IgG triggers unpolarized degranulation. In this study, we investigated the basis for this difference. IL-2-expanded human NK cells were stimulated by incubation with plate-bound ligands of LFA-1 (ICAM-1) and CD16 (human IgG). Surprisingly, LFA-1 elicited signals similar to those induced by CD16, including tyrosine phosphorylation of the TCR ζ-chain, tyrosine kinase Syk, and phospholipase C-γ. Whereas CD16 activated Ca(2+) mobilization and LAT phosphorylation, LFA-1 did not, but induced strong Pyk2 and paxillin phosphorylation. LFA-1-dependent granule polarization was blocked by inhibition of Syk, phospholipase C-γ, and protein kinase C, as well as by paxillin knockdown. Therefore, common signals triggered by CD16 and LFA-1 bifurcate to provide independent control of Ca(2+)-dependent degranulation and paxillin-dependent granule polarization.
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Affiliation(s)
- Michael E March
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
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Boyle KB, Gyori D, Sindrilaru A, Scharffetter-Kochanek K, Taylor PR, Mócsai A, Stephens LR, Hawkins PT. Class IA Phosphoinositide 3-Kinase β and δ Regulate Neutrophil Oxidase Activation in Response toAspergillus fumigatusHyphae. THE JOURNAL OF IMMUNOLOGY 2011; 186:2978-89. [DOI: 10.4049/jimmunol.1002268] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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The integrin LFA-1 signals through ZAP-70 to regulate expression of high-affinity LFA-1 on T lymphocytes. Blood 2011; 117:3331-42. [PMID: 21200022 DOI: 10.1182/blood-2010-06-289140] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The integrin lymphocyte function-associated antigen 1 (LFA-1) controls many functions of T lymphocytes and is particularly essential during lymphocyte migration from blood into tissues. LFA-1 is considered to initiate "outside-in" signaling when bound to ligand intercellular adhesion molecule 1 (ICAM-1), but little is known about the proteins involved or where in the cell such LFA-1-mediated signaling might be operating. Here we show that LFA-1 is constitutively associated with the protein tyrosine kinases Lck and zeta chain-associated protein of 70 kDa (ZAP-70). When LFA-1 binds ICAM-1, both kinases become phosphorylated and the consequence of kinase activation is the conversion of intermediate- to high-affinity LFA-1 and an increase in close contact with ICAM-1. In the polarized T lymphocyte, phospho-ZAP-70 is concentrated within a region of high-affinity LFA-1 that includes talin and encompasses the lamella/lamellipodial interface as well as further back in the cell. Deficiency of ZAP-70 through inhibition or knockdown in T lymphocytes decreases the speed of migration on ICAM-1, as well as reducing firm adhesion under shear-flow conditions. Through its control of high-affinity LFA-1, the LFA-1/Lck/ZAP-70 complex is in position to initiate the rapid adhesion strengthening and migration necessary for T-lymphocyte responses when stimulated vasculature is encountered at sites of infection or injury.
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Watzl C, Long EO. Signal transduction during activation and inhibition of natural killer cells. CURRENT PROTOCOLS IN IMMUNOLOGY 2010; Chapter 11:Unit 11.9B. [PMID: 20814939 PMCID: PMC3857016 DOI: 10.1002/0471142735.im1109bs90] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Natural killer (NK) cells are important for early immune responses to viral infections and cancer. Upon activation, NK cells secrete cytokines and chemokines, and kill sensitive target cells by releasing the content of cytolytic granules. This unit is focused on the signal transduction pathways that regulate NK cell activities in response to contact with other cells. We will highlight signals regulating NK cell adhesion to target cells and describe the induction of cellular cytotoxicity by the engagement of different NK cell activation receptors. Negative signaling induced by inhibitory receptors opposes NK cell activation and provides an important safeguard from NK cell reactivity toward normal, healthy cells. We will discuss the complex integration of the different signals that occur during interaction of NK cells with target cells.
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Affiliation(s)
- Carsten Watzl
- Institute for Immunology, University Heidelberg, Heidelberg, Germany
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Mócsai A, Ruland J, Tybulewicz VLJ. The SYK tyrosine kinase: a crucial player in diverse biological functions. Nat Rev Immunol 2010; 10:387-402. [PMID: 20467426 PMCID: PMC4782221 DOI: 10.1038/nri2765] [Citation(s) in RCA: 956] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Spleen tyrosine kinase (SYK) is known to have a crucial role in adaptive immune receptor signalling. However, recent reports indicate that SYK also mediates other, unexpectedly diverse biological functions, including cellular adhesion, innate immune recognition, osteoclast maturation, platelet activation and vascular development. SYK is activated by C-type lectins and integrins, and activates new targets, including the CARD9-BCL-10-MALT1 pathway and the NLRP3 inflammasome. Studies using Drosophila melanogaster suggest that there is an evolutionarily ancient origin of SYK-mediated signalling. Moreover, SYK has a crucial role in autoimmune diseases and haematological malignancies. This Review summarizes our current understanding of the diverse functions of SYK and how this is being translated for therapeutic purposes.
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Affiliation(s)
- Attila Mócsai
- Department of Physiology, Semmelweis University School of Medicine, 1094 Budapest, Hungary.
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Schistosoma mansoni: signal transduction processes during the development of the reproductive organs. Parasitology 2010; 137:497-520. [PMID: 20163751 DOI: 10.1017/s0031182010000053] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Among the topics of considerable interest concerning our understanding of the unusual biology of schistosomes is the sexual maturation of the female. The identification of genes coding for signal transduction proteins controlling essential steps of the pairing-dependent differentiation of the reproductive organs, vitellarium and ovary will help to substantiate our knowledge about this unique parasite. Furthermore, such signalling proteins could be potential targets to interfere with the development of this parasite to combat schistosomiasis since its pathology is caused by the eggs. This review summarises first post-genomic steps to elucidate the function of gonad-specific signalling molecules which were identified by homology-based cloning strategies, by in silico identification or by yeast two-hybrid interaction analyses, using a combination of novel techniques. These include the in vitro culture of adult schistosomes, their treatment with chemical inhibitors to block enzyme activity, the use of RNAi to silence gene function post-transcriptionally, and confocal laser scanning microscopy to study the morphological consequences of these experimental approaches. Finally, we propose a first model of protein networks that are active in the ovary regulating mitogenic activity and differentiation. Some of these molecules are also active in the testes of males, probably fulfilling similar roles as in the ovary.
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Bridges MD, Hideg K, Hubbell WL. Resolving Conformational and Rotameric Exchange in Spin-Labeled Proteins Using Saturation Recovery EPR. APPLIED MAGNETIC RESONANCE 2010; 37:363. [PMID: 20157634 PMCID: PMC2821067 DOI: 10.1007/s00723-009-0079-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The function of many proteins involves equilibria between conformational substates, and to elucidate mechanisms of function it is essential to have experimental tools to detect the presence of conformational substates and to determine the time scale of exchange between them. Site-directed spin labeling (SDSL) has the potential to serve this purpose. In proteins containing a nitroxide side chain (R1), multicomponent electron paramagnetic resonance (EPR) spectra can arise either from equilibria involving different conformational substates or rotamers of R1. To employ SDSL to uniquely identify conformational equilibria, it is thus essential to distinguish between these origins of multicomponent spectra. Here we show that this is possible based on the time scale for exchange of the nitroxide between distinct environments that give rise to multicomponent EPR spectra; rotamer exchange for R1 lies in the ≈0.1-1 μs range, while conformational exchange is at least an order of magnitude slower. The time scales of exchange events are determined by saturation recovery EPR, and in favorable cases, the exchange rate constants between substates with lifetimes of approximately 1-70 μs can be estimated by the approach.
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Affiliation(s)
- Michael D. Bridges
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-7008, USA
| | - Kálmán Hideg
- Institute of Organic and Medical Chemistry, University of Pécs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Wayne L. Hubbell
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-7008, USA
- Jules Stein Eye Institute, UCLA School of Medicine, Los Angeles, CA 90095-7008, USA
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Deshmukh K, Anamika K, Srinivasan N. Evolution of domain combinations in protein kinases and its implications for functional diversity. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2009; 102:1-15. [PMID: 20026163 DOI: 10.1016/j.pbiomolbio.2009.12.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 12/10/2009] [Indexed: 01/01/2023]
Abstract
Protein kinases phosphorylating Ser/Thr/Tyr residues in several cellular proteins exert tight control over their biological functions. They constitute the largest protein family in most eukaryotic species. Protein kinases classified based on sequence similarity in their catalytic domains, cluster into subfamilies, which share gross functional properties. Many protein kinases are associated or tethered covalently to domains that serve as adapter or regulatory modules, aiding substrate recruitment, specificity, and also serve as scaffolds. Hence the modular organisation of the protein kinases serves as guidelines to their functional and molecular properties. Analysis of genomic repertoires of protein kinases in eukaryotes have revealed wide spectrum of domain organisation across various subfamilies of kinases. Occurrence of organism-specific novel domain combinations suggests functional diversity achieved by protein kinases in order to regulate variety of biological processes. In addition, domain architecture of protein kinases revealed existence of hybrid protein kinase subfamilies and their emerging roles in the signaling of eukaryotic organisms. In this review we discuss the repertoire of non-kinase domains tethered to multi-domain kinases in the metazoans. Similarities and differences in the domain architectures of protein kinases in these organisms indicate conserved and unique features that are critical to functional specialization.
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Affiliation(s)
- Krupa Deshmukh
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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Bradley WD, Koleske AJ. Regulation of cell migration and morphogenesis by Abl-family kinases: emerging mechanisms and physiological contexts. J Cell Sci 2009; 122:3441-54. [PMID: 19759284 DOI: 10.1242/jcs.039859] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Abl-family non-receptor tyrosine kinases are essential regulators of the cytoskeleton. They transduce diverse extracellular cues into cytoskeletal rearrangements that have dramatic effects on cell motility and morphogenesis. Recent biochemical and genetic studies have revealed several mechanisms that Abl-family kinases use to mediate these effects. Abl-family kinases stimulate actin polymerization through the activation of cortactin, hematopoietic lineage cell-specific protein (HS1), WASp- and WAVE-family proteins, and Rac1. They also attenuate cell contractility by inhibiting RhoA and altering adhesion dynamics. These pathways impinge on several physiological processes, including development and maintenance of the nervous and immune systems, and epithelial morphogenesis. Elucidating how Abl-family kinases are regulated, and where and when they coordinate cytoskeletal changes, is essential for garnering a better understanding of these complex processes.
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Affiliation(s)
- William D Bradley
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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Kinetic advantage of intrinsically disordered proteins in coupled folding-binding process: a critical assessment of the "fly-casting" mechanism. J Mol Biol 2009; 393:1143-59. [PMID: 19747922 DOI: 10.1016/j.jmb.2009.09.010] [Citation(s) in RCA: 212] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 06/29/2009] [Accepted: 09/04/2009] [Indexed: 11/20/2022]
Abstract
Intrinsically disordered proteins (IDPs) are recognized to play important roles in many biological functions such as transcription and translation regulation, cellular signal transduction, protein phosphorylation, and molecular assemblies. The coupling of folding with binding through a "fly-casting" mechanism has been proposed to account for the fast binding kinetics of IDPs. In this article, experimental data from the literature were collated to verify the kinetic advantages of IDPs, while molecular simulations were performed to clarify the origin of the kinetic advantages. The phosphorylated KID-kinase-inducible domain interacting domain (KIX) complex was used as an example in the simulations. By modifying a coarse-grained model with a native-centric Gō-like potential, we were able to continuously tune the degree of disorder of the phosphorylated KID domain and thus investigate the intrinsic role of chain flexibility in binding kinetics. The simulations show that the "fly-casting" effect is not only due to the greater capture radii of IDPs. The coupling of folding with binding of IDPs leads to a significant reduction in binding free-energy barrier. Such a reduction accelerates the binding process. Although the greater capture radius has been regarded as the main factor in promoting the binding rate of IDPs, we found that this parameter will also lead to the slower translational diffusion of IDPs when compared with ordered proteins. As a result, the capture rate of IDPs was found to be slower than that of ordered proteins. The main origin of the faster binding for IDPs are the fewer encounter times required before the formation of the final binding complex. The roles of the interchain native contacts fraction (Q(b)) and the mass-center distance (DeltaR) as reaction coordinates are also discussed.
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Spalton JC, Mori J, Pollitt AY, Hughes CE, Eble JA, Watson SP. The novel Syk inhibitor R406 reveals mechanistic differences in the initiation of GPVI and CLEC-2 signaling in platelets. J Thromb Haemost 2009; 7:1192-9. [PMID: 19422460 DOI: 10.1111/j.1538-7836.2009.03451.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Syk is a key mediator of signaling pathways downstream of several platelet surface receptors including GPVI/FcRgamma collagen receptor, the C-type lectin receptor CLEC-2, and integrin alphaIIbbeta3. A recent study identified the novel small molecule R406 as a selective inhibitor of Syk. OBJECTIVES The present study evaluates the role of Syk in human platelets using the novel inhibitor R406. METHODS Agonist-induced GPVI and CLEC-2 signaling were assessed using aggregometry, immunoprecipitation and western blotting to determine the effects of R406 on platelet activation. RESULTS We demonstrate R406 to be a powerful inhibitor of Syk in human platelets. R406 abrogated shape change and aggregation induced by activation of GPVI and CLEC-2, and reduced platelet spreading on fibrinogen. The inhibitory effect of R406 was associated with inhibition of tyrosine phosphorylation of signaling proteins that lay downstream of Syk for all three receptors, including PLCgamma2. Strikingly, R406 markedly inhibited tyrosine phosphorylation of CLEC-2 and Syk downstream of CLEC-2 activation, whereas phosphorylation of Syk downstream of GPVI and integrin alphaIIbbeta3 was unaffected. CONCLUSIONS The inhibitory effect of R406 provides direct evidence of a role for Syk in GPVI, CLEC-2 and integrin alphaIIbbeta3 signaling in human platelets. Further, the results demonstrate a critical role for Syk in mediating tyrosine phosphorylation of CLEC-2, suggesting a novel model in which both Src and Syk kinases regulate tyrosine phosphorylation of the C-type lectin receptor leading to platelet activation.
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Affiliation(s)
- J C Spalton
- Centre for Cardiovascular Sciences, Institute for Biomedical Research, The College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
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Kato A, Oshimi K. Ancient ubiquitous protein 1 and Syk link cytoplasmic tails of the integrin alpha(IIb)beta(3). Platelets 2009; 20:105-10. [PMID: 19235052 DOI: 10.1080/09537100802641507] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It is currently accepted that activity of the integrin alpha(IIb)beta(3) is modulated by direct interaction between its cytoplasmic tails (CTs) and association of cytoplasmic proteins with them, and disruption of the close linkage between CTs leads to activation of alpha(IIb)beta(3) (inside-out signaling). We previously reported that ancient ubiquitous protein (Aup1) binds to the membrane-proximal sequence of integrin alphaCTs that plays a pivotal role in the inside-out signaling. To explore biological function of Aup1, we examined in this study interaction of Aup1 with Src and Syk that are quickly activated in platelets before fibrinogen binding following thrombin stimulation. By immunoprecipitation assay with resting platelets, we first found that alpha(IIb)beta(3), Src, Syk, and Aup1 are constitutively complexed. In vitro binding study with recombinant Syk and glutathione (GSH) S-transferase (GST) - Src, -Aup1, and -alpha(IIb) and - beta(3) CTs that are immobilized to GSH- beads revealed direct binding of Syk to Aup1 as well as the beta(3) CT. Dot blot analysis with synthetic peptides for alpha(IIb) and beta(3) CTs, and GST-Aup1 and -Src immobilized to PVDF membrane exhibited concordant result with the GST pull-down assay. Immunoprecipitation of platelet lysates 10 seconds after thrombin stimulation, when activity and tyrosine phosphorylation of Syk are maimum, exhibited that active Syk does not coprecipitate with Aup1. In vitro kinase assay with GST-Syk and -Aup1 proteins at the presence or absence of active Src, a potent activator of Syk, revealed that Aup1 does not directly influence activation of Syk by autophosphorylation or tyrosine phosphorylation by Src. These results indicate that Aup1 is an adaptor recruiting Syk to the alpha(IIb) CT, and suggest that the alpha(IIb) -Aup1- Syk- beta(3) complex formation links alpha(IIb) and beta(3) CTs to sustain alpha(IIb)beta(3) in an inactive state and Syk dissociates from Aup1 after activation.
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Affiliation(s)
- Atsushi Kato
- Division of Hematology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, Japan.
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Abstract
Integrins are cell surface heterodimers that bind adhesion molecules expressed on other cells or in the extracellular matrix. Integrin-mediated interactions are critical for T cell development in the thymus, migration of T cells in the periphery, and induction of T cell effector functions. In resting T cells, integrins are maintained in a low affinity state. Engagement of the T cell receptor or chemokine receptors increases integrin affinity, enabling integrins to bind their ligands and initiate a signaling cascade resulting in altered cell morphology and motility. Our laboratory is interested how adapter proteins, mediators of intracellular signal transduction, regulate both signals from the T cell receptor to integrins (inside-out signaling) and (outside-in) signals from integrins into the cell.
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The tyrosine phosphatase CD148 is an essential positive regulator of platelet activation and thrombosis. Blood 2009; 113:4942-54. [PMID: 19246339 PMCID: PMC2686144 DOI: 10.1182/blood-2008-08-174318] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Platelets play a fundamental role in hemostasis and thrombosis. They are also involved in pathologic conditions resulting from blocked blood vessels, including myocardial infarction and ischemic stroke. Platelet adhesion, activation, and aggregation at sites of vascular injury are regulated by a diverse repertoire of tyrosine kinase–linked and G protein–coupled receptors. Src family kinases (SFKs) play a central role in initiating and propagating signaling from several platelet surface receptors; however, the underlying mechanism of how SFK activity is regulated in platelets remains unclear. CD148 is the only receptor-like protein tyrosine phosphatase identified in platelets to date. In the present study, we show that mutant mice lacking CD148 exhibited a bleeding tendency and defective arterial thrombosis. Basal SFK activity was found to be markedly reduced in CD148-deficient platelets, resulting in a global hyporesponsiveness to agonists that signal through SFKs, including collagen and fibrinogen. G protein–coupled receptor responses to thrombin and other agonists were also marginally reduced. These results highlight CD148 as a global regulator of platelet activation and a novel antithrombotic drug target.
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Identification of FcgammaRIIa as the ITAM-bearing receptor mediating alphaIIbbeta3 outside-in integrin signaling in human platelets. Blood 2008; 112:2780-6. [PMID: 18641368 DOI: 10.1182/blood-2008-02-142125] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Immunoreceptor tyrosine-based activation motif (ITAM)-containing proteins have recently been demonstrated in macrophages and neutrophils to be required for cell surface integrins to transmit activation signals into the cell. To identify ITAM-bearing proteins that mediate signaling via the platelet-specific integrin alphaIIbbeta3, fibrinogen binding was induced by (1) allowing platelets to spread directly on immobilized fibrinogen, or (2) activating the PAR1 thrombin receptor on platelets in suspension. Both initiated strong, ligand binding-dependent tyrosine phosphorylation of the ITAM-bearing platelet Fc receptor, FcgammaRIIa, as well as downstream phosphorylation of the protein tyrosine kinase Syk and activation of phospholipase Cgamma2 (PLCgamma2). Addition of Fab fragments of an FcgammaRIIa-specific monoclonal antibody strongly inhibited platelet spreading on immobilized fibrinogen, as well as downstream tyrosine phosphorylation of FcgammaRIIa, Syk, and PLCgamma2, and platelets from a patient whose platelets express reduced levels of FcgammaRIIa exhibited markedly reduced spreading on immobilized fibrinogen. Finally, fibrinogen binding-induced FcgammaRIIa phosphorylation did not occur in human platelets expressing a truncated beta3 cytoplasmic domain. Taken together, these data suggest that ligand binding to platelet alphaIIbbeta3 induces integrin cytoplasmic domain-dependent phosphorylation of FcgammaRIIa, which then enlists selected components of the immunoreceptor signaling cascade to transmit amplification signals into the cell.
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Rodius S, Chaloin O, Moes M, Schaffner-Reckinger E, Landrieu I, Lippens G, Lin M, Zhang J, Kieffer N. The talin rod IBS2 alpha-helix interacts with the beta3 integrin cytoplasmic tail membrane-proximal helix by establishing charge complementary salt bridges. J Biol Chem 2008; 283:24212-23. [PMID: 18577523 DOI: 10.1074/jbc.m709704200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Talin establishes a major link between integrins and actin filaments and contains two distinct integrin binding sites: one, IBS1, located in the talin head domain and involved in integrin activation and a second, IBS2, that maps to helix 50 of the talin rod domain and is essential for linking integrin beta subunits to the cytoskeleton ( Moes, M., Rodius, S., Coleman, S. J., Monkley, S. J., Goormaghtigh, E., Tremuth, L., Kox, C., van der Holst, P. P., Critchley, D. R., and Kieffer, N. (2007) J. Biol. Chem. 282, 17280-17288 ). Through the combined approach of mutational analysis of the beta3 integrin cytoplasmic tail and the talin rod IBS2 site, SPR binding studies, as well as site-specific antibody inhibition experiments, we provide evidence that the integrin beta3-talin rod interaction relies on a helix-helix association between alpha-helix 50 of the talin rod domain and the membrane-proximal alpha-helix of the beta3 integrin cytoplasmic tail. Moreover, charge complementarity between the highly conserved talin rod IBS2 lysine residues and integrin beta3 glutamic acid residues is necessary for this interaction. Our results support a model in which talin IBS2 binds to the same face of the beta3 subunit cytoplasmic helix as the integrin alphaIIb cytoplasmic tail helix, suggesting that IBS2 can only interact with the beta3 subunit following integrin activation.
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Affiliation(s)
- Sophie Rodius
- Laboratoire de Biologie et Physiologie Intégrée (CNRS/GDRE-ITI), Université du Luxembourg, L-1511 Luxembourg, Grand-Duchy of Luxembourg
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Bajpai M, Chopra P, Dastidar SG, Ray A. Spleen tyrosine kinase: a novel target for therapeutic intervention of rheumatoid arthritis. Expert Opin Investig Drugs 2008; 17:641-59. [PMID: 18447591 DOI: 10.1517/13543784.17.5.641] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND In the last few years, significant progress has been made in understanding the pathogenic mechanisms and in defining the role of relevant cells and molecules in the pathophysiology of rheumatoid arthritis (RA). Various therapies, both biological (anti-TNF, anti-interleukins [e.g., IL-1]) and small molecule inhibitors have been explored for the treatment of RA. OBJECTIVE To date, no single signaling pathway inhibitor as wide acting as the corticosteroids, is known. However, treatment with corticosteroids is also associated with allied side effects. Despite a lot of efforts in the category of small molecule inhibitors, no inhibitor is available to deal with RA at both fronts (inflammation and tissue damage), without causing immense side effects. METHOD This present review explores the role of spleen tyrosine kinase (Syk) in the pathogenesis of RA and also discusses how it may meet the present day therapeutic requirements for the treatment of RA. This review gives an in-depth discussion on the role of Syk signaling in RA, the possibilities of using Syk as a target and also discusses the possible side effects that could be associated with its inhibition. CONCLUSION We propose Syk inhibition as a potential therapeutic approach for the treatment of RA.
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Affiliation(s)
- Malini Bajpai
- Department of Pharmacology, New Drug Discovery Research, Ranbaxy Research Laboratories, Plot No-20, Sector-18, Gurgaon-122001-Haryana, India.
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Waldeck-Weiermair M, Zoratti C, Osibow K, Balenga N, Goessnitzer E, Waldhoer M, Malli R, Graier WF. Integrin clustering enables anandamide-induced Ca2+ signaling in endothelial cells via GPR55 by protection against CB1-receptor-triggered repression. J Cell Sci 2008; 121:1704-1717. [PMID: 18445684 PMCID: PMC4067516 DOI: 10.1242/jcs.020958] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Although the endocannabinoid anandamide is frequently described to act predominantly in the cardiovascular system, the molecular mechanisms of its signaling remained unclear. In human endothelial cells, two receptors for anandamide were found, which were characterized as cannabinoid 1 receptor (CB1R; CNR1) and G-protein-coupled receptor 55 (GPR55). Both receptors trigger distinct signaling pathways. It crucially depends on the activation status of integrins which signaling cascade becomes promoted upon anandamide stimulation. Under conditions of inactive integrins, anandamide initiates CB1R-derived signaling, including Gi-protein-mediated activation of spleen tyrosine kinase (Syk), resulting in NFkappaB translocation. Furthermore, Syk inhibits phosphoinositide 3-kinase (PI3K) that represents a key protein in the transduction of GPR55-originated signaling. However, once integrins are clustered, CB1R splits from integrins and, thus, Syk cannot further inhibit GPR55-triggered signaling resulting in intracellular Ca2+ mobilization from the endoplasmic reticulum (ER) via a PI3K-Bmx-phospholipase C (PLC) pathway and activation of nuclear factor of activated T-cells. Altogether, these data demonstrate that the physiological effects of anandamide on endothelial cells depend on the status of integrin clustering.
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Affiliation(s)
| | - Cristina Zoratti
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
| | - Karin Osibow
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
| | - Nariman Balenga
- Institute of Experimental and Clinical Pharmacology, Medical University Graz, Graz, A8010, Austria
| | - Edith Goessnitzer
- Institute of Pharmaceutical Chemistry, University Graz, Graz Austria
| | - Maria Waldhoer
- Institute of Experimental and Clinical Pharmacology, Medical University Graz, Graz, A8010, Austria
| | - Roland Malli
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
| | - Wolfgang F. Graier
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
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Knobloch J, Beckmann S, Burmeister C, Quack T, Grevelding CG. Tyrosine kinase and cooperative TGFβ signaling in the reproductive organs of Schistosoma mansoni. Exp Parasitol 2007; 117:318-36. [PMID: 17553494 DOI: 10.1016/j.exppara.2007.04.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 04/06/2007] [Accepted: 04/16/2007] [Indexed: 10/23/2022]
Abstract
Drug-induced suppression of female schistosome sexual maturation is an auspicious strategy to combat schistosomiasis since the eggs are the causative agent. The establishment of drug targets requires knowledge about the molecular mechanisms that regulate the development of the female reproductive organs, which include vitellarium and ovary. This review summarizes recent studies suggesting tyrosine kinases as important factors for the regulation of female gonad development. In this context, especially cytoplasmatic tyrosine kinases of the Src class seem to play dominant roles. Moreover, experimental data and theoretical concepts are provided supporting a crosstalk between tyrosine kinase and TGFbeta signaling in the production of vitellocytes. Finally, we take advantage from the schistosome genome project to propose a model for the regulation of vitelline-cell production and differentiation.
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Affiliation(s)
- Jürgen Knobloch
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine-University, D-40225 Düsseldorf, Germany.
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Jakus Z, Fodor S, Abram CL, Lowell CA, Mócsai A. Immunoreceptor-like signaling by beta 2 and beta 3 integrins. Trends Cell Biol 2007; 17:493-501. [PMID: 17913496 DOI: 10.1016/j.tcb.2007.09.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 08/08/2007] [Accepted: 09/11/2007] [Indexed: 11/23/2022]
Abstract
Although adhesion to extracellular structures is one of the most fundamental cell biological processes, the intracellular signals triggered by integrins, the most important receptors involved, are incompletely understood. Several recent reports indicate that signaling by beta(2) and beta(3) integrins in various cell types (neutrophils, macrophages, osteoclasts and platelets) use components of the signal transduction machinery of lymphocyte antigen receptors. Central to this immunoreceptor-like signaling is the phosphorylation of immunoreceptor tyrosine-based activation motif (ITAM)-containing adapters (such as DAP12 and the Fc receptor gamma-chain) by Src-family kinases and the concomitant recruitment of the Syk tyrosine kinase through its dual SH2 domains. These and other reports reveal an unexpected similarity between the signal-transduction mechanisms used by integrins and immune recognition receptors.
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Affiliation(s)
- Zoltán Jakus
- Department of Physiology, Semmelweis University School of Medicine, 1088 Budapest, Hungary
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49
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Abstract
A common signaling pathway is known to operate downstream of immunoreceptors, such as the T-cell, B-cell, or Fc receptors, following engagement by their respective ligands. This pathway involves Src family kinase-mediated tyrosine phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) that recruit and activate spleen tyrosine kinase (Syk) or Zap70 (zeta-associated protein of 70 kDa) kinases, which in turn activate a variety of downstream signals. Evidence has been building from a variety of sources, particularly mouse models, that molecules involved in the immunoreceptor signaling pathway are also required for signals initiated by integrins. Integrins are the major cell surface receptors that mediate adhesion of leukocytes to a variety of extracellular matrix proteins and counter-receptors expressed on endothelial cells. Integrin ligation is a critical step in the activation of leukocyte effector functions (such as neutrophil degranulation or lymphocyte proliferation). Integrin signaling through pathways common to those utilized by immunoreceptors provides a mechanism by which leukocyte adhesion can regulate activation of cellular responses. In animal models, integrin-mediated signal transduction plays a critical role in inflammatory disease. In this review, we discuss the convergence of immunoreceptor and integrin signaling, focusing on how these pathways modulate leukocyte activation.
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Affiliation(s)
- Clare L Abram
- Department of Laboratory Medicine, University of California, San Francisco, CA 94143-0451, USA
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50
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Zhu J, Carman CV, Kim M, Shimaoka M, Springer TA, Luo BH. Requirement of alpha and beta subunit transmembrane helix separation for integrin outside-in signaling. Blood 2007; 110:2475-83. [PMID: 17615290 PMCID: PMC1988953 DOI: 10.1182/blood-2007-03-080077] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Adhesion to extracellular ligands through integrins regulates cell shape, migration, growth, and survival. How integrins transmit signals in the outside-to-in direction remains unknown. Whereas in resting integrins the alpha and beta subunit transmembrane domains are associated, ligand binding promotes dissociation and separation of these domains. Here we address whether such separation is required for outside-in signaling. By introduction of an intersubunit disulfide bond, we generated mutant integrin alphaIIbbeta3 with blocked transmembrane separation that binds ligand, mediates adhesion, adopts an extended conformation after ligand binding, and forms antibody-induced macroclusters on the cell surface similarly to wild type. However, the mutant integrin exhibits a profound defect in adhesion-induced outside-in signaling as measured by cell spreading, actin stress-fiber and focal adhesion formation, and focal adhesion kinase activation. This defect was rescued by reduction of the disulfide bond. Our results demonstrate that the separation of transmembrane domains is required for integrin outside-in signal transduction.
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Affiliation(s)
- Jieqing Zhu
- The CBR Institute for Biomedical Research and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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