1
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Liu G, Thangavel R, Rysted J, Kim Y, Francis MB, Adams E, Lin Z, Taugher RJ, Wemmie JA, Usachev YM, Lee G. Loss of tau and Fyn reduces compensatory effects of MAP2 for tau and reveals a Fyn-independent effect of tau on calcium. J Neurosci Res 2019; 97:1393-1413. [PMID: 31452242 PMCID: PMC6850396 DOI: 10.1002/jnr.24517] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/18/2022]
Abstract
Microtubule-associated protein tau associates with Src family tyrosine kinase Fyn and is tyrosine phosphorylated by Fyn. The presence of tyrosine phosphorylated tau in AD and the involvement of Fyn in AD has drawn attention to the tau-Fyn complex. In this study, a tau-Fyn double knockout (DKO) mouse was generated to investigate the role of the complex. DKO mice resembled Fyn KO in novel object recognition and contextual fear conditioning tasks and resembled tau KO mice in the pole test and protection from pentylenetetrazole-induced seizures. In glutamate-induced Ca2+ response, Fyn KO was decreased relative to WT and DKO had a greater reduction relative to Fyn KO, suggesting that tau may have a Fyn-independent role. Since tau KO resembled WT in its Ca2+ response, we investigated whether microtubule-associated protein 2 (MAP2) served to compensate for tau, since the MAP2 level was increased in tau KO but decreased in DKO mice. We found that like tau, MAP2 increased Fyn activity. Moreover, tau KO neurons had increased density of dendritic MAP2-Fyn complexes relative to WT neurons. Therefore, we hypothesize that in the tau KO, the absence of tau would be compensated by MAP2, especially in the dendrites, where tau-Fyn complexes are of critical importance. In the DKO, decreased levels of MAP2 made compensation more difficult, thus revealing the effect of tau in the Ca2+ response.
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Affiliation(s)
- Guanghao Liu
- Interdisciplinary Program in Neuroscience, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Ramasamy Thangavel
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jacob Rysted
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Yohan Kim
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Meghan B Francis
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Eric Adams
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Zhihong Lin
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Rebecca J Taugher
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - John A Wemmie
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Yuriy M Usachev
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Gloria Lee
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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2
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Romero MMG, McCathie G, Jankun P, Roehl HH. Damage-induced reactive oxygen species enable zebrafish tail regeneration by repositioning of Hedgehog expressing cells. Nat Commun 2018; 9:4010. [PMID: 30275454 PMCID: PMC6167316 DOI: 10.1038/s41467-018-06460-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 08/30/2018] [Indexed: 12/20/2022] Open
Abstract
Many aquatic vertebrates have a remarkable ability to regenerate limbs and tails after amputation. Previous studies indicate that reactive oxygen species (ROS) signalling initiates regeneration, but the mechanism by which this takes place is poorly understood. Developmental signalling pathways have been shown to have proregenerative roles in many systems. However, whether these are playing roles that are specific to regeneration, or are simply recapitulating their developmental functions is unclear. Here, we analyse zebrafish larval tail regeneration and find evidence that ROS released upon wounding cause repositioning of notochord cells to the damage site. These cells secrete Hedgehog ligands that are required for regeneration. Hedgehog signalling is not required for normal tail development suggesting that it has a regeneration-specific role. Our results provide a model for how ROS initiate tail regeneration, and indicate that developmental signalling pathways can play regenerative functions that are not directly related to their developmental roles. Reactive oxygen species (ROS) are required to initiate regeneration but the mechanisms regulating its production are unclear. Here, the authors show in zebrafish larval tail regeneration that ROS is released by mobilised notochord cells enables their repositioning in the damage site, assisted by secreted Hh.
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Affiliation(s)
- Maria Montserrat Garcia Romero
- Bateson Centre, Department of Biomedical Sciences, The University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Gareth McCathie
- Bateson Centre, Department of Biomedical Sciences, The University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Philip Jankun
- Bateson Centre, Department of Biomedical Sciences, The University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Henry Hamilton Roehl
- Bateson Centre, Department of Biomedical Sciences, The University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.
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3
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Kim DJ, Norden PR, Salvador J, Barry DM, Bowers SLK, Cleaver O, Davis GE. Src- and Fyn-dependent apical membrane trafficking events control endothelial lumen formation during vascular tube morphogenesis. PLoS One 2017; 12:e0184461. [PMID: 28910325 PMCID: PMC5598984 DOI: 10.1371/journal.pone.0184461] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/24/2017] [Indexed: 01/10/2023] Open
Abstract
Here we examine the question of how endothelial cells (ECs) develop their apical membrane surface domain during lumen and tube formation. We demonstrate marked apical membrane targeting of activated Src kinases to this apical domain during early and late stages of this process. Immunostaining for phosphotyrosine or phospho-Src reveals apical membrane staining in intracellular vacuoles initially. This is then followed by vacuole to vacuole fusion events to generate an apical luminal membrane, which is similarly decorated with activated phospho-Src kinases. Functional blockade of Src kinases completely blocks EC lumen and tube formation, whether this occurs during vasculogenic tube assembly or angiogenic sprouting events. Multiple Src kinases participate in this apical membrane formation process and siRNA suppression of Src, Fyn and Yes, but not Lyn, blocks EC lumen formation. We also demonstrate strong apical targeting of Src-GFP and Fyn-GFP fusion proteins and increasing their expression enhances lumen formation. Finally, we show that Src- and Fyn-associated vacuoles track and fuse along a subapically polarized microtubule cytoskeleton, which is highly acetylated. These vacuoles generate the apical luminal membrane in a stereotypically polarized, perinuclear position. Overall, our study identifies a critical role for Src kinases in creating and decorating the EC apical membrane surface during early and late stages of lumen and tube formation, a central event in the molecular control of vascular morphogenesis.
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Affiliation(s)
- Dae Joong Kim
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Dalton Cardiovascular Research Center, Columbia, MO, United States of America
| | - Pieter R Norden
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Dalton Cardiovascular Research Center, Columbia, MO, United States of America
| | - Jocelynda Salvador
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Dalton Cardiovascular Research Center, Columbia, MO, United States of America
| | - David M Barry
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas TX, United States of America
| | - Stephanie L K Bowers
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Dalton Cardiovascular Research Center, Columbia, MO, United States of America
| | - Ondine Cleaver
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas TX, United States of America
| | - George E Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Dalton Cardiovascular Research Center, Columbia, MO, United States of America
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4
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An L, Liu S, Zhang W, Zhang Y, Huang Y, Hu X, Chen S, Zhao S. Mouse Fyn induces pseudopodium formation in Chinese hamster ovary cells. J Vet Sci 2013; 15:111-5. [PMID: 24378585 PMCID: PMC3973753 DOI: 10.4142/jvs.2014.15.1.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/23/2013] [Indexed: 11/20/2022] Open
Abstract
Molecular mechanisms underlying the effects of Fyn on cell morphology, pseudopodium movement, and cell migration were investigated. The Fyn gene was subcloned into pEGFP-N1 to produce pEGFP-N1-Fyn. Chinese hamster ovary (CHO) cells were transfected with pEGFP-N1-Fyn. The expression of Fyn mRNA and proteins was monitored by reverse transcription-PCR and Western blotting. Additionally, transfected cells were stained with 4',6-diamidino-2-phenylindole and a series of time-lapse images was taken. Sequences of the recombinant plasmids pMD18-T-Fyn and pEGFP-N1-Fyn were confirmed by sequence identification using National Center for Biotechnology Information in USA, and Fyn expression was detected by RT-PCR and Western blotting. The morphology of CHO cells transfected with the recombinant vector was significantly altered. Fyn expression induced filopodia and lamellipodia formation. Based on these results, we concluded that overexpression of mouse Fyn induces the formation of filopodia and lamellipodia in CHO cells, and promotes cell movement.
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Affiliation(s)
- Lei An
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
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5
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Dráber P, Sulimenko V, Dráberová E. Cytoskeleton in mast cell signaling. Front Immunol 2012; 3:130. [PMID: 22654883 PMCID: PMC3360219 DOI: 10.3389/fimmu.2012.00130] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 05/05/2012] [Indexed: 11/13/2022] Open
Abstract
Mast cell activation mediated by the high affinity receptor for IgE (FcεRI) is a key event in allergic response and inflammation. Other receptors on mast cells, as c-Kit for stem cell factor and G protein-coupled receptors (GPCRs) synergistically enhance the FcεRI-mediated release of inflammatory mediators. Activation of various signaling pathways in mast cells results in changes in cell morphology, adhesion to substrate, exocytosis, and migration. Reorganization of cytoskeleton is pivotal in all these processes. Cytoskeletal proteins also play an important role in initial stages of FcεRI and other surface receptors induced triggering. Highly dynamic microtubules formed by αβ-tubulin dimers as well as microfilaments build up from polymerized actin are affected in activated cells by kinases/phosphatases, Rho GTPases and changes in concentration of cytosolic Ca(2+). Also important are nucleation proteins; the γ-tubulin complexes in case of microtubules or Arp 2/3 complex with its nucleation promoting factors and formins in case of microfilaments. The dynamic nature of microtubules and microfilaments in activated cells depends on many associated/regulatory proteins. Changes in rigidity of activated mast cells reflect changes in intermediate filaments build up from vimentin. This review offers a critical appraisal of current knowledge on the role of cytoskeleton in mast cells signaling.
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Affiliation(s)
- Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Vadym Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
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6
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Reinhold A, Reimann S, Reinhold D, Schraven B, Togni M. Expression of SKAP-HOM in DCs is required for an optimal immune response in vivo. J Leukoc Biol 2009; 86:61-71. [PMID: 19369640 DOI: 10.1189/jlb.0608344] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The cytosolic adaptor molecule SKAP-HOM, similar to the T cell-specific homologue SKAP55, interacts directly with ADAP, and both molecules are involved in inside-out signaling. Previous studies have shown that in the absence of SKAP-HOM, antigen receptor-triggered integrin-mediated adhesion is impaired severely in B cells but not in T cells. In addition, loss of SKAP-HOM results in a less severe clinical course of EAE. DCs are the most potent APCs and express SKAP-HOM. However, the role of SKAP-HOM in DCs remains unknown. Here, we assessed whether the reduced severity of EAE observed in SKAP-HOM-deficient mice is at least partially a result of an impaired cooperation between APCs and T cells. We demonstrate that migration of LC in vivo and the spontaneous motility of BMDCs in vitro are increased in the absence of SKAP-HOM. In contrast, triggering of the integrin results in a drastic decrease of DC motility and in enhanced actin polymerization in SKAP-HOM-deficient DCs. Furthermore, the antigen-dependent conjugate formed between wild-type T cells and SKAP-HOM(-/-) DCs is delayed in comparison with wild-type DCs. Strikingly, fewer antigen-specific T cells are induced by immunization with SKAP-HOM(-/-) BMDCs as compared with wild-type BMDCs in vivo. Thus, these findings suggest that SKAP-HOM expression in DCs is required for the induction of an optimal immune response.
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Affiliation(s)
- Annegret Reinhold
- Institute of Molecular and Clinical Immunology, Otto von Guericke University, Magdeburg, Germany
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7
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Ma X, Sayeski PP. Identification of tubulin as a substrate of Jak2 tyrosine kinase and its role in Jak2-dependent signaling. Biochemistry 2007; 46:7153-62. [PMID: 17530781 DOI: 10.1021/bi700101n] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Jak2 is a nonreceptor tyrosine kinase that acts in numerous cellular signal transduction systems. Here, large amounts of recombinant Jak2 protein were expressed in eukaryotic cells, and an unknown 55 kDa protein was copurified with it. Mass spectrometry and Western blot analysis identified the 55 kDa protein as the alpha- and beta-isoforms of tubulin. Biochemical experiments determined that Jak2 and tubulin specifically coassociate with one another, and the region of Jak2 that binds tubulin is the pseudokinase domain. Immunofluoresence indicated that Jak2 and tubulin (microtubules) colocalize within intact cells. The functional consequence of the coassociation between Jak2 and tubulin is that Jak2 phosphorylates tubulin on tyrosine residues. Specifically, in response to growth hormone, tubulin was phosphorylated in a Jak2-dependent manner. Tubulin was also found to interact with signal transducers and activators of transcription 1 (STAT1) and be involved in STAT1 nuclear transport. As such, this work suggests that tubulin is a substrate of Jak2 and facilitates Jak2/STAT1-dependent signaling.
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Affiliation(s)
- Xianyue Ma
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, P.O. Box 100274, Gainesville, Florida 32610, USA
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8
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Huang SY, Chen YH, Teng SH, Chen IC, Ho LL, Tu CF. Protein expression of lymphocytes in HLA-DR transgenic pigs by a proteomic approach. Proteomics 2006; 6:5815-25. [PMID: 17022099 DOI: 10.1002/pmic.200600054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Matching donor and recipient human leucocyte antigen (HLA-II) could conquer cell-mediated rejection following transplantation. Transgenic pigs carrying HLA genes that "humanize" porcine organs, tissues, and cells were successfully generated. This study further clarifies the effect of HLA-DR transgenes on lymphocyte protein expression, via a proteomic approach. Lymphocytes were isolated from two HLA-DR transgenic pigs and three nontransgenic littermates on 157 d after birth. Soluble protein of 1x10(7) cells was separated using 2-DE. In total, 301 colloidal CBB-stained protein spots detected on all five 2-D gels were quantified. Thirty-three proteins were differentially expressed by a factor of 1.5. These proteins were subsequently identified by MALDI-TOF MS and MALDI-TOF/TOF MS/MS. These proteins were sorted into the following categories: chaperones, T-lymphocyte function, DNA/RNA processing, cytoskeleton-associated proteins, signal transduction, enzymes, and unknown. Previous studies have suggested that some of the identified proteins are associated with lymphocyte activation/proliferation. The identities of the unidentified spots and the systematic effect of these up- and down-regulated proteins on T-cell function in HLA-DR transgenic pigs require further exploration.
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Affiliation(s)
- San-Yuan Huang
- Division of Biotechnology, Animal Technology Institute Taiwan, Miaoli, Taiwan
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9
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Sulimenko V, Dráberová E, Sulimenko T, Macurek L, Richterová V, Dráber P, Dráber P. Regulation of microtubule formation in activated mast cells by complexes of gamma-tubulin with Fyn and Syk kinases. THE JOURNAL OF IMMUNOLOGY 2006; 176:7243-53. [PMID: 16751367 DOI: 10.4049/jimmunol.176.12.7243] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aggregation of the high-affinity IgE receptors (FcepsilonRIs) on the surface of granulated mast cells initiates a chain of signaling events culminating in the release of allergy mediators. Although microtubules are involved in mast cell degranulation, the molecular mechanism that controls microtubule rearrangement after FcepsilonRI triggering is poorly understood. In this study, we show that the activation of bone marrow-derived mast cells (BMMCs) induced by FcepsilonRI aggregation or treatment with pervanadate leads to a rapid polymerization of microtubules. This polymerization was not dependent on the presence of Lyn kinase as determined by experiments with BMMCs isolated from Lyn-negative mice. One of the key regulators of microtubule polymerization is gamma-tubulin. Immunoprecipitation experiments revealed that gamma-tubulin from activated cells formed complexes with Fyn and Syk protein tyrosine kinases and several tyrosine phosphorylated proteins from both wild-type and Lyn(-/-) BMMCs. Pretreatment of the cells with Src-family or Syk-family selective tyrosine kinase inhibitors, PP2 or piceatannol, respectively, inhibited the formation of microtubules and reduced the amount of tyrosine phosphorylated proteins in gamma-tubulin complexes, suggesting that Src and Syk family kinases are involved in the initial stages of microtubule formation. This notion was corroborated by pull-down experiments in which gamma-tubulin complex bounds to the recombinant Src homology 2 and Src homology 3 domains of Fyn kinase. We propose that Fyn and Syk kinases are involved in the regulation of binding properties of gamma-tubulin and/or its associated proteins, and thus modulate the microtubule nucleation in activated mast cells.
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Affiliation(s)
- Vadym Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague
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10
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Huet D, Bagot M, Loyaux D, Capdevielle J, Conraux L, Ferrara P, Bensussan A, Marie-Cardine A. SC5 mAb represents a unique tool for the detection of extracellular vimentin as a specific marker of Sezary cells. THE JOURNAL OF IMMUNOLOGY 2006; 176:652-9. [PMID: 16365461 DOI: 10.4049/jimmunol.176.1.652] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Circulating malignant Sézary lymphocytes result from a clonal proliferation of memory/activated CD4(+)CD45RO(+) T lymphocytes primarily involving the skin. Recently, the CD158k/KIR3DL2 cell surface receptor has been identified to phenotypically characterize these cells. We previously described a mAb termed SC5 that identifies an unknown early activation cell membrane molecule. It is expressed selectively by T lymphocytes isolated from healthy individuals upon activation, and by circulating Sézary syndrome lymphocytes. In addition, we found that SC5 mAb was reactive with all resting T lymphocytes once permeabilized, indicating that SC5 mAb-reactive molecule might present distinct cellular localization according to the T cell activation status. In this study, we show for the first time that SC5 mAb recognizes the intermediate filament protein vimentin when exported to the extracellular side of the plasma membrane of viable Sézary malignant cells. We demonstrate that SC5 mAb is unique as it reacts with both viable malignant lymphocytes and apoptotic T cells. As vimentin is also detected rapidly at the cell membrane surface after normal T lymphocyte activation, it suggests that its extracellular detection on Sézary cells could be a consequence of their constitutive activation status. Finally, as a probable outcome of vimentin cell surface expression, autoantibodies against vimentin were found in the sera of Sézary syndrome patients.
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Affiliation(s)
- Delphine Huet
- Institut National de la Santé et de la Recherche Médicale Unité 659, University of Paris XII, Medical School of Créteil, Henri Mondor Hospital, Department of Dermatology, Créteil, France
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11
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Gevaert K, Staes A, Van Damme J, De Groot S, Hugelier K, Demol H, Martens L, Goethals M, Vandekerckhove J. Global phosphoproteome analysis on human HepG2 hepatocytes using reversed-phase diagonal LC. Proteomics 2006; 5:3589-99. [PMID: 16097034 DOI: 10.1002/pmic.200401217] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We present a phosphoproteomics approach using diagonal RP chromatography as the basic isolation principle. Phosphopeptides present in a tryptic digest of total cellular lysates were first enriched by Fe3+-immobilized metal ion affinity chromatography. Further sorting of the phosphopeptides took place in three steps. First, the resulting peptide mixture was fractionated over reversed-phase chromatography. Second, peptides present in each fraction were treated with phosphatases. Third, the dephosphorylated peptides were then more hydrophobic and shifted towards a later elution interval from the contaminating non-phosphopeptides eluting at the same position as during the primary run. Since the phosphopeptides are isolated as their dephosphorylated form, additional proof for their original phosphorylation state was obtained by split-differential 16O-18O labeling. The method was validated with alpha-casein phosphopeptides and consecutively applied on HepG2 cells. We identified 190 phosphorylated peptides from 152 different proteins. This dataset includes 38 novel protein phosphorylation sites.
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Affiliation(s)
- Kris Gevaert
- Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology, Ghent University, Ghent, Belgium
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12
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Togni M, Swanson KD, Reimann S, Kliche S, Pearce AC, Simeoni L, Reinhold D, Wienands J, Neel BG, Schraven B, Gerber A. Regulation of in vitro and in vivo immune functions by the cytosolic adaptor protein SKAP-HOM. Mol Cell Biol 2005; 25:8052-63. [PMID: 16135797 PMCID: PMC1234325 DOI: 10.1128/mcb.25.18.8052-8063.2005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
SKAP-HOM is a cytosolic adaptor protein representing a specific substrate for the Src family protein tyrosine kinase Fyn. Previously, several groups have provided experimental evidence that SKAP-HOM (most likely in cooperation with the cytosolic adaptor protein ADAP) is involved in regulating leukocyte adhesion. To further assess the physiological role of SKAP-HOM, we investigated the immune system of SKAP-HOM-deficient mice. Our data show that T-cell responses towards a variety of stimuli are unaffected in the absence of SKAP-HOM. Similarly, B-cell receptor (BCR)-mediated total tyrosine phosphorylation and phosphorylation of Erk, p38, and JNK, as well as immunoreceptor-mediated Ca(2+) responses, are normal in SKAP-HOM(-/-) animals. However, despite apparently normal membrane-proximal signaling events, BCR-mediated proliferation is strongly attenuated in the absence of SKAP-HOM(-/-). In addition, adhesion of activated B cells to fibronectin (a ligand for beta1 integrins) as well as to ICAM-1 (a ligand for beta2 integrins) is strongly reduced. In vivo, the loss of SKAP-HOM results in a less severe clinical course of experimental autoimmune encephalomyelitis following immunization of mice with the encephalitogenic peptide of MOG (myelin oligodendrocyte glycoprotein). This is accompanied by strongly reduced serum levels of MOG-specific antibodies and lower MOG-specific T-cell responses. In summary, our data suggest that SKAP-HOM is required for proper activation of the immune system, likely by regulating the cross-talk between immunoreceptors and integrins.
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Affiliation(s)
- M Togni
- Institute of Immunology, Otto von Guericke University, Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany
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13
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Teckchandani AM, Birukova AA, Tar K, Verin AD, Tsygankov AY. The multidomain protooncogenic protein c-Cbl binds to tubulin and stabilizes microtubules. Exp Cell Res 2005; 306:114-27. [PMID: 15878338 DOI: 10.1016/j.yexcr.2005.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 01/27/2005] [Accepted: 02/15/2005] [Indexed: 11/18/2022]
Abstract
The protooncogenic protein c-Cbl is known to regulate the actin cytoskeleton. In this study, we present results indicating that c-Cbl can also regulate the microtubular network. We have shown that c-Cbl binds to tubulin and microtubules through its tyrosine kinase binding (TKB) domain. However, the character of the interactions described in this report is novel, since the G306E mutation, which disrupts the ability of c-Cbl's TKB to bind to tyrosine-phosphorylated proteins, does not affect the observed interaction between c-Cbl and microtubules. Furthermore, overexpression of c-Cbl in human pulmonary artery endothelial cells and COS-7 cells leads to microtubule stabilization. We demonstrate that this effect of c-Cbl is mediated by TKB, and, like c-Cbl binding to microtubules, is independent of the ability of TKB to bind to tyrosine-phosphorylated proteins. Finally, we have shown that c-Cbl directly polymerizes microtubules in vitro, and that TKB is necessary and sufficient for this effect of c-Cbl. In this last phenomenon, as well as in the previous ones, the effect of TKB is not sensitive to the inactivating G306E mutation. Overall, the results presented in this report suggest a novel function for c-Cbl-microtubule binding and stabilization.
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Affiliation(s)
- Anjali M Teckchandani
- Department of Microbiology and Immunology, Temple University School of Medicine, 3400 N. Broad Street, Philadelphia, PA 19140, USA
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14
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Zamora-Leon SP, Shafit-Zagardo B. Disruption of the actin network enhances MAP-2c and Fyn-induced process outgrowth. ACTA ACUST UNITED AC 2005; 62:110-23. [PMID: 16145685 DOI: 10.1002/cm.20090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We investigated the interaction of MAP-2c and Fyn in the initiation of process outgrowth in COS7 cells. Single transfections of Fyn and MAP-2c resulted in a dramatic decrease in flat, rounded COS7 cells, and a significant increase in both the number of cells with multiple short, spike-like processes, and cells with longer processes. Co-transfection of Fyn and MAP-2c resulted in an additive increase in the number of cells with more than two processes and discrete sites of co-localization within processes. When single or double transfected cells were treated with cytochalasin D or lantrunculin there was a dramatic increase in the number of cells with more than two processes. In addition, there was an increase in the length of the processes, both in single and double transfected cells, suggesting that the actin meshwork provides a barrier for MT-based process extension. When co-transfected cells were post-treated with nocodazole, Fyn was not associated with MAP-2c and acetylated, stable tubulin. Although some Fyn/MAP-2c co-localization was retained, punctate staining of MAP-2c and Fyn were observed at the cell periphery, in areas devoid of stable MTs. Mutations in either tyrosine 67 (Tyr67), a site on human MAP-2c phosphorylated by Fyn, or a second tyrosine residue (Tyr50), did not alter the ability of MAP-2c and Fyn to induce process outgrowth. These studies suggest that independent of one another MAP-2c and Fyn are able to induce process outgrowth and in concert can initiate and enhance process outgrowth in an additive manner.
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Affiliation(s)
- S Pilar Zamora-Leon
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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15
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Abstract
Rho GTPases are molecular switches controlling a broad range of cellular processes including lymphocyte activation. Not surprisingly, Rho GTPases are now recognized as pivotal regulators of antigen-specific T cell activation by APCs and immunological synapse formation. This review summarizes recent advances in our understanding of how Rho GTPase-dependent pathways control T lymphocyte motility, polarization and activation.
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Affiliation(s)
- M Deckert
- INSERM Unit 576, Hôpital de l'Archet, BP3079, 06202 Nice, France.
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16
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Laurent CE, Delfino FJ, Cheng HY, Smithgall TE. The human c-Fes tyrosine kinase binds tubulin and microtubules through separate domains and promotes microtubule assembly. Mol Cell Biol 2004; 24:9351-8. [PMID: 15485904 PMCID: PMC522259 DOI: 10.1128/mcb.24.21.9351-9358.2004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The c-Fes protein-tyrosine kinase (Fes) has been implicated in the differentiation of vascular endothelial, myeloid hematopoietic, and neuronal cells, promoting substantial morphological changes in these cell types. The mechanism by which Fes promotes morphological aspects of cellular differentiation is unknown. Using COS-7 cells as a model system, we observed that Fes strongly colocalizes with microtubules in vivo when activated via coiled-coil mutation or by coexpression with an active Src family kinase. In contrast, wild-type Fes showed a diffuse cytoplasmic localization in this system, which correlated with undetectable kinase activity. Coimmunoprecipitation and immunofluorescence microscopy showed that the N-terminal Fes/CIP4 homology (FCH) domain is involved in Fes interaction with soluble unpolymerized tubulin. However, the FCH domain was not required for colocalization with polymerized microtubules in vivo. In contrast, a functional SH2 domain was essential for microtubule localization of Fes, consistent with the strong tyrosine phosphorylation of purified tubulin by Fes in vitro. Using a microtubule nucleation assay, we observed that purified c-Fes also catalyzed extensive tubulin polymerization in vitro. Taken together, these results identify c-Fes as a regulator of the tubulin cytoskeleton that may contribute to Fes-induced morphological changes in myeloid hematopoietic and neuronal cells.
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Affiliation(s)
- Charles E Laurent
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, E1240 Biomedical Science Tower, Pittsburgh, PA 15261, USA
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17
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Zamora-Leon SP, Bresnick A, Backer JM, Shafit-Zagardo B. Fyn phosphorylates human MAP-2c on tyrosine 67. J Biol Chem 2004; 280:1962-70. [PMID: 15536091 DOI: 10.1074/jbc.m411380200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The Src homology 3 (SH3) domain of Fyn binds to a conserved PXXP motif on microtubule-associated protein-2. Co-transfections into COS7 cells and in vitro kinase assays performed with Fyn and wild-type, or mutant MAP-2c, determined that Fyn phosphorylated MAP-2c on tyrosine 67. The phosphorylation generated a consensus sequence for the binding of the SH2 domain of Grb2 (pYSN). Pull-down assays with SH2-Grb2 from human fetal brain homogenates, and co-immunoprecipitation of Grb2 and MAP-2 confirmed the interaction in vivo, and demonstrated that MAP-2c is tyrosine-phosphorylated in human fetal brain. Filter overlay assays confirmed that the SH2 domain of Grb2 binds to human MAP-2c following incubation with active Fyn. Enzyme-linked immunosorbent assays confirmed the interaction between the SH2 domain of Grb2 and a tyrosine-phosphorylated MAP-2 peptide spanning the pY(67)SN motif. Thus, MAP-2c can directly recruit multiple signaling proteins important for central nervous system development.
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Affiliation(s)
- S Pilar Zamora-Leon
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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18
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Talmor-Cohen A, Tomashov-Matar R, Tsai WB, Kinsey WH, Shalgi R. Fyn kinase–tubulin interaction during meiosis of rat eggs. Reproduction 2004; 128:387-93. [PMID: 15454633 DOI: 10.1530/rep.1.00266] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prior to fertilization, the spindle of vertebrate eggs must remain stable and well organized during the second meiotic meta-phase arrest (MII). In a previous study we have determined that the completion of meiosis is a Src family kinase (SFK)-dependent event. In the current study we have used the SFK inhibitors, SU6656 and PP2, and demonstrated that inhibition of SFKs caused the formation of a disorganized spindle. The observation that proper organization of an MII spindle is an SFK-dependent process, combined with our previous finding that Fyn kinase is localized at the microtubules (MTs), prompted us to examine the potential role of Fyn in MT signaling. Our results show an association between Fyn and tubulin, the ability of Fyn to phosphorylate tubulinin vitroand stimulation of meiosis completion by injection of a constitutively active form of Fyn (CAF).We suggested that SFKs mediate significant functions during the organization of the MII spindle. In view of CAF injection experiments, and of the pronounced concentration of Fyn kinase at the spindle, we propose that Fyn may play an important role in some aspects of the spindle functions, possibly those involving the MTs.
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Affiliation(s)
- A Talmor-Cohen
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Ramat-Aviv 69978 Tel-Aviv, Israel
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19
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Serrador JM, Cabrero JR, Sancho D, Mittelbrunn M, Urzainqui A, Sánchez-Madrid F. HDAC6 deacetylase activity links the tubulin cytoskeleton with immune synapse organization. Immunity 2004; 20:417-28. [PMID: 15084271 DOI: 10.1016/s1074-7613(04)00078-0] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2003] [Revised: 02/06/2004] [Accepted: 02/10/2004] [Indexed: 11/29/2022]
Abstract
We investigated the role of acetylated microtubules in the antigen-specific interaction of T helper and antigen-presenting cells (APCs). In T cells, acetylated microtubules concentrated at contact site with APCs, surrounding clusters of CD3 and LFA-1. TcR engagement induced a transient deacetylation of microtubules at early times and an enhanced acetylation at late times. Confocal videomicroscopy studies revealed that the HDAC6 tubulin deacetylase was translocated and concentrated at the contact site of T cells with APCs. Overexpression of HDAC6 but not a dead deacetylase mutant in T cells disorganized CD3 and LFA-1 at the immune synapse. This effect was reverted by treatment with the deacetylase inhibitor trichostatin A. The antigen-specific translocation of the microtubule organizing center (MTOC) and IL-2 production were also severely impaired by overexpression of HDAC6. Our results underscore the key role for HDAC6 in the organization of the immune synapse and the antigen-specific reorientation of the MTOC.
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Affiliation(s)
- Juan M Serrador
- Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, E-28006 Madrid, Spain
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20
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Sancho D, Vicente-Manzanares M, Mittelbrunn M, Montoya MC, Gordón-Alonso M, Serrador JM, Sánchez-Madrid F. Regulation of microtubule-organizing center orientation and actomyosin cytoskeleton rearrangement during immune interactions. Immunol Rev 2002; 189:84-97. [PMID: 12445267 DOI: 10.1034/j.1600-065x.2002.18908.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The reorganization of membrane, cytoskeletal and signaling molecules during immune interactions is critical for the generation of immune response. At the initiation of the T cell-antigen presenting cell (APC) interaction, antigen-independent weak adhesion forces allow the scanning of the APC surface by the T cell receptor for specific antigens. The stabilization of T cell-APC conjugates involves the segregation of membrane and intracellular signaling proteins, driven by reorganization of membrane microdomains and cytoskeletal changes. In early T cell-APC cognate interactions, the microtubular cytoskeleton undergoes drastic changes that lead to microtubule-organizing center (MTOC) reorientation to the vicinity of the cell-cell contact area. Recent data on the dynamics of MTOC redistribution and its influence in T cell-APC conjugate stabilization, together with the description of an increasing number of signaling molecules associated to this complex, underscore the key role of MTOC translocation in the T cell response. We focus on the mechanisms that control the early MTOC reorientation during T cell-APC interaction and the relevance of this process to T cell activation.
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Affiliation(s)
- David Sancho
- Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain
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21
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Process outgrowth of oligodendrocytes is promoted by interaction of fyn kinase with the cytoskeletal protein tau. J Neurosci 2002. [PMID: 11826099 DOI: 10.1523/jneurosci.22-03-00698.2002] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Fyn kinase plays an important role during myelination and has been shown to promote morphological differentiation of cultured oligodendrocytes. We analyzed the downstream targets of Fyn kinase in oligodendrocytes. Because process outgrowth and wrapping of axons involve cytoskeletal rearrangement, we focused on cytoskeletal proteins linked to Fyn. Here we demonstrate that Fyn binds to the cytoskeletal proteins Tau and alpha-Tubulin in oligodendrocytes. Tau interacts with the Fyn SH3 domain whereas alpha-Tubulin binds to the Fyn SH2 and SH3 domains. To study the function of the Fyn-Tau interaction in oligodendrocytes, we designed a Tau deletion mutant that would compete with endogenous Tau-Fyn binding in transfected cells. The mutant Tau protein binds to the Fyn SH3 domain but lacks the microtubuli interaction domain and thus cannot bind to microtubuli. In the presence of the mutant Tau protein, a reduction of the process number and process length in oligodendroglial cells was observed. This effect is likely to be caused by interference with the Fyn-Tau-microtubuli cascade rather than inactivation of the kinase, because Fyn bound to the mutant Tau retains activity. A similar inhibition of process outgrowth was observed when oliogodendroglial cells were cultured in the presence of Fumonisin B1, an inhibitor of sphingolipid synthesis that prevents the formation of rafts. Because ligation of the cell adhesion molecule F3 on oligodendrocytes leads to activation of Fyn kinase localized in rafts, these findings suggest that recruitment of Tau and Tubulin to activated Fyn kinase in rafts is an important step in the initiation of myelination.
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22
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Zamora-Leon SP, Lee G, Davies P, Shafit-Zagardo B. Binding of Fyn to MAP-2c through an SH3 binding domain. Regulation of the interaction by ERK2. J Biol Chem 2001; 276:39950-8. [PMID: 11546790 DOI: 10.1074/jbc.m107807200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Microtubule-associated protein 2 (MAP-2) isoforms are developmentally expressed in the nervous system and contain a number of functional domains. Adjacent to the first repeat of the microtubule-binding domain is an RTPPKSP motif for binding SH3 domains. To identify SH3-containing proteins that interact with MAP-2, transfections, filter overlay assays, glutathione S-transferase (GST)-mediated binding assays, co-immunoprecipitations and enzyme-linked immunosorbent assays were performed. Transfections of MAP-2a, MAP-2b, and MAP-2c constructs into COS7 cells, followed by incubation of the cell lysates with SH3-GST fusion proteins, determined that the strongest interaction was between MAP-2c and the non-receptor tyrosine kinase Fyn; however, MAP-2b and MAP-2c also bound to Grb2. Co-immunoprecipitation of Fyn and MAP-2c from human fetal homogenates confirmed the interaction in vivo. MAP-2 synthetic peptides spanning the RTPPKSP motif bound to Fyn, and the interaction was regulated by phosphorylation. Co-transfections with MAP-2c and the extracellular signal-regulated kinase 2 (ERK2) demonstrated that MAP-2c is threonine/serine-phosphorylated on its RTPPKSP motif and that threonine phosphorylation abolished the MAP-2c/Fyn binding. Kinase assays and co-transfection of MAP-2c and Fyn confirmed that Fyn tyrosine kinase phosphorylates MAP-2c. Thus, the activation of signaling pathways may regulate cytoskeletal dynamics by altering the state of phosphorylation of MAP-2 by both ERK2 and Fyn kinase.
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Affiliation(s)
- S P Zamora-Leon
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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23
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Yamada T, Aoyama Y, Owada MK, Kawakatsu H, Kitajima Y. Scraped-wounding causes activation and association of C-Src tyrosine kinase with microtubules in cultured keratinocytes. Cell Struct Funct 2000; 25:351-9. [PMID: 11280705 DOI: 10.1247/csf.25.351] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In order to elucidate the function of c-Src in keratinocytes, we studied the intracellular distribution of its active and inactive form in cultured normal human keratinocyte, using anti-c-Src monoclonal antibody clone 28, which recognizes the active form of c-Src (dephosphorylated at COOH-terminal residue Tyr 530), and monoclonal antibody clone 327 which recognizes both active and inactive forms. Since c-Src has been suggested to be involved in the control of cell adhesion in other cells, we produced a dynamic condition of cell migration by cutting culture cell colonies into squares to form a mesh pattern with a blade (culture wound model). Before cutting, the active form was expressed in cells located only at the periphery of colonies or isolated migrating cells, and was associated with microtubules. Wounding the colony generated a dramatic and rapid activation of c-Src in a few rows of cells along the cut edges, which were made even at the middle of colony, resulting in the association of the active form with microtubules. This increase of the active form was also detected by immunoblotting of cell extracts. These reactions were inhibited by 1 mM sodium orthovanadate, a protein-tyrosine phosphatase inhibitor. ST 638, a potent Src family tyrosine kinase inhibitor, inhibited the migration of keratinocytes in the culture wound healing model. These results suggest that wounding the culture causes activation of c-Src in keratinocytes, and thus activated c-Src may play a role in the function of microtubules during cell migration, especially at an early stage of wound healing.
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Affiliation(s)
- T Yamada
- Department of Dermatology, Gifu University School of Medicine, Tsukasamachi, Japan
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24
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Faruki S, Geahlen RL, Asai DJ. Syk-dependent phosphorylation of microtubules in activated B-lymphocytes. J Cell Sci 2000; 113 ( Pt 14):2557-65. [PMID: 10862713 DOI: 10.1242/jcs.113.14.2557] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Syk is a protein-tyrosine kinase that is essential for B-lymphocyte development and B-cell signaling. Syk phosphorylates tubulin on tyrosine both in vitro and in intact lymphocytes. Here we show that (alpha)-tubulin present within the cytoskeletal microtubule network was phosphorylated in a Syk-dependent manner following the activation of B-cells by engagement of the B-cell antigen receptor or by treatment with the phosphotyrosine phosphatase inhibitor, pervanadate. Immunofluorescence staining of microtubule cytoskeletons and western blotting studies with antibodies to phosphotyrosine confirmed the phosphorylation of polymerized tubulin in Syk-expressing, but not Syk-deficient, cells. At low concentrations of pervanadate, centrosomes appeared to be preferentially tyrosine-phosphorylated. Tubulin phosphorylated to a high stoichiometry on tyrosine assembled into microtubules in vitro, and preassembled microtubules were also phosphorylated by Syk kinase in vitro. Thus, Syk has the capacity to interact with microtubule networks within the B-lymphocyte and catalyzes the phosphorylation of the (alpha)-tubulin subunit. Syk-dependent phosphorylation of microtubules may affect the ability of the microtubule cytoskeleton to serve as a platform upon which signaling complexes are assembled.
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Affiliation(s)
- S Faruki
- Department of Biological Sciences and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, USA
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25
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Dráberová L, Dráberová E, Surviladze Z, Dráber P, Dráber P. Protein tyrosine kinase p53/p56(lyn) forms complexes with gamma-tubulin in rat basophilic leukemia cells. Int Immunol 1999; 11:1829-39. [PMID: 10545487 DOI: 10.1093/intimm/11.11.1829] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The aggregation of receptors with high affinity for IgE (FcepsilonRI) on the surface of mast cells and basophils initiates a chain of biochemical events culminating in the release of allergy mediators. Although microtubules have been implicated in the activation process, the molecular mechanism of their interactions with signal transduction molecules is poorly understood. Here we show that in rat basophilic leukemia cells large amounts of alphabeta-tubulin dimers ( approximately 70%) and gamma-tubulin ( approximately 85%) are found in a soluble pool which was released from the cells after permeabilization with saponin, or extraction with non-ionic detergents. Soluble tubulins were found in large complexes with other molecules. Complexes of soluble gamma-tubulin released from activated cells contained tyrosine-phosphorylated proteins of relative mol. wt approximately 25, 50, 53, 56, 60, 75, 80, 97, 115 and 200 kDa. Increased tyrosine phosphorylation of proteins associated with the cytoskeleton, i.e. around centrosomes, was detected by immunofluorescence microscopy. In vitro kinase assays revealed increased tyrosine phosphorylation of proteins in gamma-tubulin complexes isolated from activated cells. Two of the tyrosine phosphorylated proteins in these complexes were identified as the p53/56(lyn) kinase. Furthermore, gamma-tubulin bound to the N-terminal fragment of recombinant Lyn kinase and its binding was slightly enhanced in activated cells. Pretreatment of the cells with Src family-selective tyrosine kinase inhibitor, PP1, decreased the amount of tyrosine phosphorylated proteins in gamma-tubulin complexes, as well as the amount of gamma-tubulin in Lyn kinase immunocomplexes. The combined data suggest that gamma-tubulin is involved in early stages of mast cell activation.
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Affiliation(s)
- L Dráberová
- Department of Mammalian Gene Expression and Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic
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26
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da Cruz LA, Penfold S, Zhang J, Somani AK, Shi F, McGavin MK, Song X, Siminovitch KA. Involvement of the lymphocyte cytoskeleton in antigen-receptor signaling. Curr Top Microbiol Immunol 1999; 245:135-67. [PMID: 10533312 DOI: 10.1007/978-3-642-57066-7_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- L A da Cruz
- Department of Medicine, University of Toronto, Ontario, Canada
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27
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Ron D, Napolitano EW, Voronova A, Vasquez NJ, Roberts DN, Calio BL, Caothien RH, Pettiford SM, Wellik S, Mandac JB, Kauvar LM. Direct interaction in T-cells between thetaPKC and the tyrosine kinase p59fyn. J Biol Chem 1999; 274:19003-10. [PMID: 10383400 DOI: 10.1074/jbc.274.27.19003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The protein kinase C (PKC) family has been clearly implicated in T-cell activation as have several nonreceptor protein-tyrosine kinases associated with the T-cell receptor, including p59fyn. This report demonstrates that thetaPKC and p59fyn specifically interact in vitro, in the yeast two-hybrid system, and in T-cells. Further indications of direct interaction are that p59fyn potentiates thetaPKC catalytic activity and that thetaPKC is a substrate for tyrosine phosphorylation by p59fyn. This interaction may account for the localization of thetaPKC following T-cell activation, pharmacological disruption of which results in specific cell-signaling defects. The demonstration of a physical interaction between a PKC and a protein-tyrosine kinase expands the class of PKC-anchoring proteins (receptors for activated C kinases (RACKs)) and demonstrates a direct connection between these two major T-cell-signaling pathways.
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Affiliation(s)
- D Ron
- Telik, Inc., South San Francisco, California 94080, USA
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28
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Altman A, Deckert M. The function of small GTPases in signaling by immune recognition and other leukocyte receptors. Adv Immunol 1999; 72:1-101. [PMID: 10361572 DOI: 10.1016/s0065-2776(08)60017-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- A Altman
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA
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29
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Rodríguez-Fernández JL, Gómez M, Luque A, Hogg N, Sánchez-Madrid F, Cabañas C. The interaction of activated integrin lymphocyte function-associated antigen 1 with ligand intercellular adhesion molecule 1 induces activation and redistribution of focal adhesion kinase and proline-rich tyrosine kinase 2 in T lymphocytes. Mol Biol Cell 1999; 10:1891-907. [PMID: 10359604 PMCID: PMC25386 DOI: 10.1091/mbc.10.6.1891] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Integrin receptors play a central role in the biology of lymphocytes, mediating crucial functional aspects of these cells, including adhesion, activation, polarization, migration, and signaling. Here we report that induction of activation of the beta2-integrin lymphocyte function-associated antigen 1 (LFA-1) in T lymphocytes with divalent cations, phorbol esters, or stimulatory antibodies is followed by a dramatic polarization, resulting in a characteristic elongated morphology of the cells and the arrest of migrating lymphoblasts. This cellular polarization was prevented by treatment of cells with the specific tyrosine kinase inhibitor genistein. Furthermore, the interaction of the activated integrin LFA-1 with its ligand intercellular adhesion molecule 1 induced the activation of the cytoplasmic tyrosine kinases focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (PYK-2). FAK activation reached a maximum after 45 min of stimulation; in contrast, PYK-2 activation peaked at 30 min, declining after 60 min. Upon polarization of lymphoblasts, FAK and PYK-2 redistributed from a diffuse localization in the cytoplasm to a region close to the microtubule-organizing center in these cells. FAK and PYK-2 activation was blocked when lymphoblasts were pretreated with actin and tubulin cytoskeleton-interfering agents, indicating its cytoskeletal dependence. Our results demonstrate that interaction of the beta2-integrin LFA-1 with its ligand intercellular adhesion molecule 1 induces remodeling of T lymphocyte morphology and activation and redistribution of the cytoplasmic tyrosine kinases FAK and PYK-2.
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Affiliation(s)
- J L Rodríguez-Fernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain
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30
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Marie-Cardine A, Kirchgessner H, Bruyns E, Shevchenko A, Mann M, Autschbach F, Ratnofsky S, Meuer S, Schraven B. SHP2-interacting transmembrane adaptor protein (SIT), a novel disulfide-linked dimer regulating human T cell activation. J Exp Med 1999; 189:1181-94. [PMID: 10209036 PMCID: PMC2193021 DOI: 10.1084/jem.189.8.1181] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
T lymphocytes express several low molecular weight transmembrane adaptor proteins that recruit src homology (SH)2 domain-containing intracellular molecules to the cell membrane via tyrosine-based signaling motifs. We describe here a novel molecule of this group termed SIT (SHP2 interacting transmembrane adaptor protein). SIT is a disulfide-linked homodimeric glycoprotein that is expressed in lymphocytes. After tyrosine phosphorylation by src and possibly syk protein tyrosine kinases SIT recruits the SH2 domain-containing tyrosine phosphatase SHP2 via an immunoreceptor tyrosine-based inhibition motif. Overexpression of SIT in Jurkat cells downmodulates T cell receptor- and phytohemagglutinin-mediated activation of the nuclear factor of activated T cells (NF-AT) by interfering with signaling processes that are probably located upstream of activation of phospholipase C. However, binding of SHP2 to SIT is not required for inhibition of NF-AT induction, suggesting that SIT not only regulates NF-AT activity but also controls NF-AT unrelated pathways of T cell activation involving SHP2.
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Affiliation(s)
- A Marie-Cardine
- Immunomodulation Laboratory of the Institute for Immunology, University of Heidelberg, 69120 Heidelberg, Germany
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31
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Abstract
Two-dimensional gel electrophoresis of anti-p59fyn immunoprecipitates obtained from non-transformed resting human T lymphocytes resulted in the identification of an oligomeric protein complex which is constitutively formed between Fyn and several additional phosphoproteins (pp43, pp72, pp85, the protein tyrosine kinase Pyk2, as well as the two recently cloned adaptor proteins, SKAP55 and SLAP-130). With the exception of pp85, these proteins seem to preferentially interact with Fyn since they are not detectable in Lck immunoprecipitates prepared under the same experimental conditions. Among the individual members of the Fyn-complex pp85, SKAP55 and pp43 are constitutively phosphorylated on tyrosine residue(s) in vivo and likely interact with Fyn via its src homology 2 (SH2)-domain. In contrast to non-transformed T lymphocytes, continuously proliferating transformed human T cell lines express an altered Fyn-complex. Thus, despite normal expression and tyrosine phosphorylation, SKAP55 does not associate with Fyn in Jurkat cells and in other human T cell lines. Instead two novel proteins interact with Fyn among which one has previously been identified as alpha-tubulin. Importantly, almost identical alterations of the Fyn-complex as observed in Jurkat cells are induced in non-transformed T lymphocytes following mitogenic stimulation. These data suggest that Fyn and its associated proteins could be involved in the control of human T cell proliferation. Moreover, the analogous constitutive alterations in transformed T cell lines could indicate that deregulation of the Fyn-complex might be functionally associated with the malignant phenotype of these cells.
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Affiliation(s)
- A Marie-Cardine
- Institute for Immunology, Immunomodulation Laboratory, Ruprecht-Karls University of Heidelberg, Germany.
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32
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Abstract
Although molecular components of signal transduction pathways are rapidly being identified, how elements of these pathways are positioned spatially and how signals traverse the intracellular environment from the cell surface to the nucleus or to other cytoplasmic targets are not well understood. The discovery of signaling molecules that interact with microtubules (MTs), as well as the multiple effects on signaling pathways of drugs that destabilize or hyperstabilize MTs, indicate that MTs are likely to be critical to the spatial organization of signal transduction. MTs themselves are also affected by signaling pathways and this may contribute to the transmission of signals to downstream targets.
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Affiliation(s)
- G G Gundersen
- Department of Anatomy and Cell Biology Columbia University 630 West 168th Street New York NY 10032 USA.
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33
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Fernandez JA, Keshvara LM, Peters JD, Furlong MT, Harrison ML, Geahlen RL. Phosphorylation- and activation-independent association of the tyrosine kinase Syk and the tyrosine kinase substrates Cbl and Vav with tubulin in B-cells. J Biol Chem 1999; 274:1401-6. [PMID: 9880513 DOI: 10.1074/jbc.274.3.1401] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aggregation of the B-cell antigen receptor leads to the activation of the 72-kDa Syk protein-tyrosine kinase and the phosphorylation of tubulin on tyrosine. To explore the requirement of Syk catalytic activity for tubulin phosphorylation, tubulin was isolated from cytosolic fractions from anti-IgM-activated B-cells (DT40) that lacked endogenous Syk and immunoblotted with anti-phosphotyrosine antibodies. Tubulin was not tyrosine-phosphorylated in Syk- B-cells. Phosphorylation could be restored by the expression of wild-type, but not catalytically inactive, Syk. However, both catalytically inactive and wild-type Syk were capable of constitutive association with tubulin, indicating that tubulin phosphorylation is not required for this interaction. Anti-phosphotyrosine antibody immunoblotting of proteins adsorbed to colchicine-agarose revealed the presence of three major tubulin-associated phosphoproteins of 110, 90, and 74 kDa, the phosphorylation of which was dependent on Syk expression. The proteins of 110 and 90 kDa were identified as Cbl and Vav, two proto-oncogene products known to become prominently phosphorylated following receptor engagement. Both proteins were shown to be constitutively associated with tubulin.
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Affiliation(s)
- J A Fernandez
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, USA
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Marie-Cardine A, Verhagen AM, Eckerskorn C, Schraven B. SKAP-HOM, a novel adaptor protein homologous to the FYN-associated protein SKAP55. FEBS Lett 1998; 435:55-60. [PMID: 9755858 DOI: 10.1016/s0014-5793(98)01040-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A recombinant GST-Fyn-SH2 domain was used to purify proteins from lysates of pervanadate treated EL4 cells. N-terminal sequencing and molecular cloning of one of the purified polypeptides resulted in the identification of a novel adaptor protein that shares strong structural homology to the recently cloned Fyn-associated adaptor protein SKAP55. This protein was termed SKAP-HOM (SKAP55 homologue). Despite their striking homology, SKAP55 and SKAP-HOM have distinct characteristics. Thus, unlike SKAP55, which is exclusively expressed in T lymphocytes, SKAP-HOM expression is ubiquitous. Furthermore, while SKAP55 is constitutively tyrosine phosphorylated in resting human T cells, SKAP-HOM is expressed as a non-phosphorylated protein in the absence of external stimulus but becomes phosphorylated following T cell activation. In addition, SKAP-HOM does not associate with p59fyn in T cells although it represents a specific substrate for the kinase in COS cells. Finally, we demonstrate that, as previously shown for SKAP55, SKAP-HOM interacts with the recently identified polypeptide SLAP-130.
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Affiliation(s)
- A Marie-Cardine
- Ruprecht-Karls University of Heidelberg, Institute for Immunology, Germany.
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Campbell KS, Cooper S, Dessing M, Yates S, Buder A. Interaction of p59 fyn Kinase with the Dynein Light Chain, Tctex-1, and Colocalization During Cytokinesis. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.4.1728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The protein tyrosine kinase p59fyn (Fyn) plays important roles in both lymphocyte Ag receptor signaling and cytokinesis of proB cells. We utilized yeast two-hybrid cloning to identify the product of the tctex-1 gene as a protein that specifically interacts with Fyn, but not with other Src family kinases. Tctex-1 was recently identified as a component of the dynein cytoskeletal motor complex. The capacity of a Tctex-1-glutathione S-transferase fusion protein to effectively bind Fyn from cell lysates confirmed the authenticity of this interaction. Tctex-1 binding required the first 19 amino acids of Fyn and integrity of two lysine residues within this sequence that were previously shown to be important for Fyn interactions with the immunoreceptor tyrosine-based activation motifs (ITAMs) of lymphocyte Ag receptors. Expression of tctex-1 mRNA and protein was observed in all lymphoma lines analyzed, and immunofluorescence confocal microscopy localized the protein to the perinuclear region. Analysis of a T cell hybridoma revealed prominent colocalization of Tctex-1 and Fyn at the cleavage furrow and mitotic spindles in cells undergoing cytokinesis. Our results provide a unique insight into a mechanism by which Tctex-1 might mediate specific recruitment of Fyn to the dynein complex in lymphocytes, which may be a critical event in mediating the previously defined role of Fyn in cytokinesis.
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Affiliation(s)
| | | | - Mark Dessing
- Basel Institute for Immunology, Basel, Switzerland
| | - Sol Yates
- Basel Institute for Immunology, Basel, Switzerland
| | - Annie Buder
- Basel Institute for Immunology, Basel, Switzerland
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36
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Bruyns E, Marie-Cardine A, Kirchgessner H, Sagolla K, Shevchenko A, Mann M, Autschbach F, Bensussan A, Meuer S, Schraven B. T cell receptor (TCR) interacting molecule (TRIM), a novel disulfide-linked dimer associated with the TCR-CD3-zeta complex, recruits intracellular signaling proteins to the plasma membrane. J Exp Med 1998; 188:561-75. [PMID: 9687533 PMCID: PMC2212462 DOI: 10.1084/jem.188.3.561] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The molecular mechanisms regulating recruitment of intracellular signaling proteins like growth factor receptor-bound protein 2 (Grb2), phospholipase Cgamma1, or phosphatidylinositol 3-kinase (PI3-kinase) to the plasma membrane after stimulation of the T cell receptor (TCR)- CD3-zeta complex are not very well understood. We describe here purification, tandem mass spectrometry sequencing, molecular cloning, and biochemical characterization of a novel transmembrane adaptor protein which associates and comodulates with the TCR-CD3-zeta complex in human T lymphocytes and T cell lines. This protein was termed T cell receptor interacting molecule (TRIM). TRIM is a disulfide-linked homodimer which is comprised of a short extracellular domain of 8 amino acids, a 19-amino acid transmembrane region, and a 159-amino acid cytoplasmic tail. In its intracellular domain, TRIM contains several tyrosine-based signaling motifs that could be involved in SH2 domain-mediated protein-protein interactions. Indeed, after T cell activation, TRIM becomes rapidly phosphorylated on tyrosine residues and then associates with the 85-kD regulatory subunit of PI3-kinase via an YxxM motif. Thus, TRIM represents a TCR-associated transmembrane adaptor protein which is likely involved in targeting of intracellular signaling proteins to the plasma membrane after triggering of the TCR.
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Affiliation(s)
- E Bruyns
- Institute for Immunology, University of Heidelberg, 69120 Heidelberg, Germany
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37
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Kumar GL, Keil TA. Olfactory dendrites of the silkmoth antheraea polyphemus cramer (Lepidoptera : Saturniidae) : immunofluorescent staining of cytoskeletal proteins and transmission electron microscopy. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s0020-7322(98)00008-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Lowin-Kropf B, Shapiro VS, Weiss A. Cytoskeletal polarization of T cells is regulated by an immunoreceptor tyrosine-based activation motif-dependent mechanism. J Cell Biol 1998; 140:861-71. [PMID: 9472038 PMCID: PMC2141749 DOI: 10.1083/jcb.140.4.861] [Citation(s) in RCA: 196] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Binding of a T cell to an appropriate antigen-presenting cell (APC) induces the rapid reorientation of the T cell cytoskeleton and secretory apparatus towards the cell-cell contact site in a T cell antigen receptor (TCR) and peptide/major histocompatibility complex-dependent process. Such T cell polarization directs the delivery of cytokines and cytotoxic mediators towards the APC and contributes to the highly selective and specific action of effector T cells. To study the signaling pathways that regulate cytoskeletal rearrangements in T lymphocytes, we set up a conjugate formation assay using Jurkat T cells as effectors and cell-sized latex beads coated with various antibodies as artificial APCs. Here, we report that beads coated with antibodies specific for the TCR-CD3 complex were sufficient to induce T cell polarization towards the bead attachment site, as judged by reorientation of the microtubule-organizing center (MTOC) and localized actin polymerization. Thus, these cytoskeletal changes did not depend on activation of additional coreceptors. Moreover, single subunits of the TCR complex, namely TCR-zeta and CD3epsilon, were equally effective in inducing cytoskeletal polarization. However, mutagenesis of the immunoreceptor tyrosine-based activation motifs (ITAMs), present three times in TCR-zeta and once in CD3epsilon, revealed that the induction of cytoskeletal rearrangements required the presence of at least one intact ITAM. In agreement with this result, lack of functional Lck, the protein tyrosine kinase responsible for ITAM phosphorylation, abolished both MTOC reorientation and polarized actin polymerization. Both inhibitor and transient overexpression studies demonstrated that MTOC reorientation could occur in the absence of Ras activation. Our results suggest that APC-induced T cell polarization is a TCR-mediated event that is coupled to the TCR by the same signaling motif as TCR-induced gene activation, but diverges in its distal signaling requirements.
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Affiliation(s)
- B Lowin-Kropf
- Department of Medicine, University of California, San Francisco, San Francisco, California 94143, USA
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Role of Immunoreceptor Tyrosine-Based Activation Motif in Signal Transduction from Antigen and Fc Receptors**Received for publication October 7, 1997. Adv Immunol 1998. [DOI: 10.1016/s0065-2776(08)60608-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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40
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Henke RC, Seeto GS, Jeffrey PL. Thy-1 and AvGp50 signal transduction complex in the avian nervous system: c-Fyn and G alpha i protein association and activation of signalling pathways. J Neurosci Res 1997; 49:655-70. [PMID: 9335254 DOI: 10.1002/(sici)1097-4547(19970915)49:6<655::aid-jnr1>3.0.co;2-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have previously reported the isolation of two distinct populations of detergent resistant membrane complexes (DRMC's) from day-old chick brain (Henke et al.: J Neurosci Res 45:617-630, 1996). We now show that the glycosylphosphatidylinositol-anchored proteins Thy-1 and AvGp50 are associated in a signalling complex with c-Fyn, the heterotrimeric G alpha i subfamily members G alpha i-3, G alpha z, and G alpha o, alpha and beta tubulin, and a number of other phosphoproteins in immunocomplexes isolated from both populations of DRMC's. Activation of this signalling complex via Thy-1 monoclonal antibody incubation with chick forebrain cells, elicited a decrease in total phosphoprotein profile and tyrosine kinase activity present in DRMC fractions isolated from these cells, while AvGp50 and control antibodies had no effect. Down-regulation of the DRMC phosphoprotein profile was accompanied by an increase in the Thy-1-associated signalling complex, suggesting that activation of this complex initiates the decreases seen in overall DRMC kinase activity. This signalling complex provides the basis for GPI-anchored protein-mediated signal transduction within the unique plasma membrane domains represented by DRMC's.
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Affiliation(s)
- R C Henke
- Development Neurobiology Unit, Children's Medical Research Institute, Wentworthville, NSW, Australia
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Marie-Cardine A, Bruyns E, Eckerskorn C, Kirchgessner H, Meuer SC, Schraven B. Molecular cloning of SKAP55, a novel protein that associates with the protein tyrosine kinase p59fyn in human T-lymphocytes. J Biol Chem 1997; 272:16077-80. [PMID: 9195899 DOI: 10.1074/jbc.272.26.16077] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In human T-lymphocytes the Src family protein tyrosine kinase p59(fyn) associates with three phosphoproteins of 43, 55, and 85 kDa (pp43, pp55, and pp85). Employing a GST-Fyn-Src homology 2 (SH2) domain fusion protein pp55 was purified from lysates of Jurkat T-cells. Molecular cloning of the pp55 cDNA reveals that the pp55 gene codes for a so far nondescribed polypeptide of 359 amino acids that comprises a pleckstrin homology domain, a C-terminal SH3 domain, as well as several potential tyrosine phosphorylation sites, among which one fulfills the criteria to bind Src-like SH2 domains with high affinity. Consistent with this observation, pp55 selectively binds to isolated SH2 domains of Lck, Lyn, Src, and Fyn but not to the SH2 domains of ZAP70, Syk, Shc, SLP-76, Grb2, phosphatidylinositol 3-kinase, and c-abl in vitro. Based on these properties the protein was termed SKAP55 (src kinase-associated phosphoprotein of 55 kDa). Northern blot analysis shows that SKAP55 mRNA is preferentially expressed in lymphatic tissues. SKAP55 is detected in resting human T-lymphocytes as a constitutively tyrosine phosphorylated protein that selectively interacts with p59(fyn). These data suggest that SKAP55 represents a novel adaptor protein likely involved in Fyn-mediated signaling in human T-lymphocytes.
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Affiliation(s)
- A Marie-Cardine
- Ruprecht-Karls University Heidelberg, Institute of Immunology, 69120 Heidelberg, Germany. /de
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42
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Schraven B, Marie-Cardine A, Koretzky G. Molecular analysis of the fyn-complex: cloning of SKAP55 and SLAP-130, two novel adaptor proteins which associate with fyn and may participate in the regulation of T cell receptor-mediated signaling. Immunol Lett 1997; 57:165-9. [PMID: 9232446 DOI: 10.1016/s0165-2478(97)00053-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- B Schraven
- Institute for Immunology, Ruprechts-Karls University of Heidelberg, Germany.
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43
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Pheromone stimulation induces cytoskeletal changes in olfactory dendrites of male silkmoths (Lepidoptera, Saturniidae, Bombycidae). Naturwissenschaften 1996. [DOI: 10.1007/bf01144018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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