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Raggi L, Tissi C, Mazzucato A, Negri V. Molecular polymorphism related to flowering trait variation in a Phaseolus vulgaris L. collection. Plant Sci 2014; 215-216:180-9. [PMID: 24388529 DOI: 10.1016/j.plantsci.2013.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/31/2013] [Accepted: 11/05/2013] [Indexed: 05/19/2023]
Abstract
The aim of this study was to investigate the flowering variation and the molecular polymorphism in key regulatory genes that control flowering in a Phaseolus vulgaris L. collection of 94 accessions from Europe and the Americas. The analysis of variance revealed that the difference in days-to-flowering between accessions was significant, with European accessions characterized by flowering precocity. Population structure analysis corroborated previous data on the genetic distinction between the Andean and Mesoamerican gene pools. A low level of admixture was detected. Genomic sequences of 15 gene fragments were obtained. About 7.0 kb per accession were sequenced and a total of 48 nucleotide substitutions identified. A Mixed Linear Model analysis, including population structure and kinship, was used to identify marker-trait associations. Haplotype tagging single nucleotide polymorphisms (htSNPs) associated with the studied traits were detected: in PvVRN1 and PvPHYB with days-to-flowering, in PvMYB29 with number of flower buds per inflorescence and in PvTFL1z and PvFCA with inflorescence length. The two genes associated with days-to-flowering control belong to the photoperiod and vernalization pathways. In particular, the PvVRN1 gene appears to play an important role in regulating the adaptation process of common bean.
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Affiliation(s)
- Lorenzo Raggi
- Dipartimento di Biologia Applicata, Università degli Studi di Perugia, 06121 Perugia, Italy.
| | - Carlo Tissi
- Dipartimento di Biologia Applicata, Università degli Studi di Perugia, 06121 Perugia, Italy.
| | - Andrea Mazzucato
- Dipartimento di Scienze e Tecnologie per l'Agricoltura, le Foreste, la Natura e l'Energia, Università degli Studi della Tuscia, 01100 Viterbo, Italy.
| | - Valeria Negri
- Dipartimento di Biologia Applicata, Università degli Studi di Perugia, 06121 Perugia, Italy.
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Kim K, Kim JH, Moon JB, Lee J, Kwak HB, Park YW, Kim N. The transmembrane adaptor protein, linker for activation of T cells ( LAT), regulates RANKL-induced osteoclast differentiation. Mol Cells 2012; 33:401-6. [PMID: 22382685 PMCID: PMC3887798 DOI: 10.1007/s10059-012-0009-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 01/26/2012] [Accepted: 01/27/2012] [Indexed: 12/22/2022] Open
Abstract
RANKL induces the formation of osteoclasts, which are responsible for bone resorption. Herein we investigate the role of the transmembrane adaptor proteins in RANKL-induced osteoclastogenesis. LAT positively regulates osteoclast differentiation and is up-regulated by RANKL via c-Fos and NFATc1, whereas LAB and LIME act as negative modulators of osteoclastogenesis. In addition, silencing of LAT by RNA interference or overexpression of a LAT dominant negative in bone marrow-derived macrophage cells attenuates RANKL-induced osteoclast formation. Furthermore, LAT is involved in RANKL-induced PLC(γ) activation and NFATc1 induction. Thus, our data suggest that LAT acts as a positive regulator of RANKL-induced osteoclastogenesis.
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Affiliation(s)
- Kabsun Kim
- National Research Laboratory for Regulation of Bone Metabolism and Disease, Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-746,
Korea
| | - Jung Ha Kim
- National Research Laboratory for Regulation of Bone Metabolism and Disease, Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-746,
Korea
| | - Jang Bae Moon
- National Research Laboratory for Regulation of Bone Metabolism and Disease, Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-746,
Korea
| | - Jongwon Lee
- National Research Laboratory for Regulation of Bone Metabolism and Disease, Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-746,
Korea
| | - Han bok Kwak
- National Research Laboratory for Regulation of Bone Metabolism and Disease, Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-746,
Korea
| | | | - Nacksung Kim
- National Research Laboratory for Regulation of Bone Metabolism and Disease, Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-746,
Korea
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Mahon RN, Sande OJ, Rojas RE, Levine AD, Harding CV, Boom WH. Mycobacterium tuberculosis ManLAM inhibits T-cell-receptor signaling by interference with ZAP-70, Lck and LAT phosphorylation. Cell Immunol 2012; 275:98-105. [PMID: 22507872 PMCID: PMC3352599 DOI: 10.1016/j.cellimm.2012.02.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 11/18/2022]
Abstract
Immune evasion is required for Mycobacterium tuberculosis to survive in the face of robust CD4(+) T cell responses. We have shown previously that M. tuberculosis cell wall glycolipids, including mannose capped lipoarabinomannan (ManLAM), directly inhibit polyclonal murine CD4(+) T cell activation by blocking ZAP-70 phosphorylation. We extended these studies to antigen-specific murine CD4(+) T cells and primary human T cells and found that ManLAM inhibited them as well. Lck and LAT phosphorylation also were inhibited by ManLAM without affecting their localization to lipid rafts. Inhibition of proximal TCR signaling was temperature sensitive, suggesting that ManLAM insertion into T cell membranes was required. Thus, M. tuberculosis ManLAM inhibits antigen-specific CD4(+) T cell activation by interfering with very early events in TCR signaling through ManLAM's insertion in T cell membranes.
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Affiliation(s)
- Robert N Mahon
- Department of Pathology, Case Western Reserve University and University Hospitals Case Medical Center, Cleveland, OH 44106, United States.
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Abstract
In vitro studies have revealed that T cell activation occurs during the formation of either dynamic or stable interactions with antigen-presenting cells (APC), and the respective cell junctions have been referred to as immunological kinapses and synapses. However, the relevance and molecular dynamics of kinapses and synapses remain to be established in vivo. Using two-photon imaging, we tracked the distribution of LAT-EGFP molecules during antigen recognition by activated CD4(+) T cells in lymph nodes. At steady state, LAT-EGFP molecules were preferentially found at the uropod of rapidly migrating T cells. In contrast to naïve T cells that fully stopped upon systemic antigen delivery, recently activated T cells decelerated and formed kinapses, characterized by continuous extension of membrane protrusions and by the absence of persistent LAT-EGFP clustering. On the other hand, activated CD4(+) T cells formed stable immunological synapses with antigen-loaded B cells and displayed sustained accumulation of LAT-EGFP fluorescence at the contact zone. Our results show that the state of T cell activation and the type of APC largely influence T cell-APC contact dynamics in lymph nodes. Furthermore, we provide a dynamic look at immunological kinapses and synapses in lymph nodes and suggest the existence of distinct patterns of LAT redistribution during antigen recognition.
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Affiliation(s)
- Georges A. Azar
- G5 Dynamiques des Réponses Immunes, Institut Pasteur, 75015 Paris, France
- Institut National de la Santé et de la Recherche Médicale U668, Equipe Avenir, 75015 Paris, France; and
| | - Fabrice Lemaître
- G5 Dynamiques des Réponses Immunes, Institut Pasteur, 75015 Paris, France
- Institut National de la Santé et de la Recherche Médicale U668, Equipe Avenir, 75015 Paris, France; and
| | - Ellen A. Robey
- Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley, CA 94720
| | - Philippe Bousso
- G5 Dynamiques des Réponses Immunes, Institut Pasteur, 75015 Paris, France
- Institut National de la Santé et de la Recherche Médicale U668, Equipe Avenir, 75015 Paris, France; and
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Carroll-Portillo A, Spendier K, Pfeiffer J, Griffiths G, Li H, Lidke KA, Oliver JM, Lidke DS, Thomas JL, Wilson BS, Timlin JA. Formation of a mast cell synapse: Fc epsilon RI membrane dynamics upon binding mobile or immobilized ligands on surfaces. J Immunol 2010; 184:1328-38. [PMID: 20042583 PMCID: PMC3087819 DOI: 10.4049/jimmunol.0903071] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Fc epsilonRI on mast cells form a synapse when presented with mobile, bilayer-incorporated Ag. In this study, we show that receptor reorganization within the contacting mast cell membrane is markedly different upon binding of mobile and immobilized ligands. Rat basophilic leukemia mast cells primed with fluorescent anti-DNP IgE were engaged by surfaces presenting either bilayer-incorporated, monovalent DNP-lipid (mobile ligand), or chemically cross-linked, multivalent DNP (immobilized ligand). Total internal reflection fluorescence imaging and electron microscopy methods were used to visualize receptor reorganization at the contact site. The spatial relationships of Fc epsilonRI to other cellular components at the synapse, such as actin, cholesterol, and linker for activation of T cells, were also analyzed. Stimulation of mast cells with immobilized polyvalent ligand resulted in typical levels of degranulation. Remarkably, degranulation also followed interaction of mast cells, with bilayers presenting mobile, monovalent ligand. Receptors engaged with mobile ligand coalesce into large, cholesterol-rich clusters that occupy the central portion of the contacting membrane. These data indicate that Fc epsilonRI cross-linking is not an obligatory step in triggering mast cell signaling and suggest that dense populations of mobile receptors are capable of initiating low-level degranulation upon ligand recognition.
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Affiliation(s)
- Amanda Carroll-Portillo
- Department of Pathology, University of New Mexico, Albuquerque, New Mexico 87131, USA
- Biofuels and Defense Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185-0895
| | - Kathrin Spendier
- Department of Physics and Astronomy and Spatiotemporal Modeling Center, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Janet Pfeiffer
- Department of Pathology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Gary Griffiths
- Imaging Probe Development Center, NIH, NHLBI, Bethesda, MD 20892
| | - Haitao Li
- Imaging Probe Development Center, NIH, NHLBI, Bethesda, MD 20892
| | - Keith A. Lidke
- Department of Physics and Astronomy and Spatiotemporal Modeling Center, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Janet M. Oliver
- Department of Pathology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Diane S. Lidke
- Department of Pathology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - James L. Thomas
- Department of Physics and Astronomy and Spatiotemporal Modeling Center, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Bridget S. Wilson
- Department of Pathology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Jerilyn A. Timlin
- Biofuels and Defense Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185-0895
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Hughes CE, Auger JM, McGlade J, Eble JA, Pearce AC, Watson SP. Differential roles for the adapters Gads and LAT in platelet activation by GPVI and CLEC-2. J Thromb Haemost 2008; 6:2152-9. [PMID: 18826392 PMCID: PMC2710801 DOI: 10.1111/j.1538-7836.2008.03166.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 08/25/2008] [Indexed: 11/27/2022]
Abstract
BACKGROUND The adapter proteins SLP-76 and LAT have been shown to play critical roles in the activation of PLCgamma2 in platelets downstream of GPVI/FcRgamma and the C-type lectin receptor CLEC-2. SLP-76 is constitutively associated with the adapter Gads in platelets, which also binds to tyrosine phosphorylated LAT, thereby providing a potential pathway of regulation of SLP-76. OBJECTIVE In the present study, we have compared the role of Gads alongside that of LAT following activation of the major platelet glycoprotein receptors using mice deficient in the two adapter proteins. RESULTS Gads was found to be required for the efficient onset of aggregation and secretion in response to submaximal stimulation of GPVI and CLEC-2, but to be dispensable for activation following stronger stimulation of the two receptors. Gads was also dispensable for spreading induced through integrin alpha(IIb)beta(3) or the GPIb-IX-V complex. Further, Gads plays a negligible role in aggregate formation on collagen at an arteriolar rate of shear. In stark contrast, platelets deficient in the adapter LAT exhibit a marked decrease in aggregation and secretion following activation of GPVI and CLEC-2, and are unable to form stable aggregates on collagen at arteriolar shear. CONCLUSIONS The results demonstrate that Gads plays a key role in linking the adapter LAT to SLP-76 in response to weak activation of GPVI and CLEC-2 whereas LAT is required for full activation over a wider range of agonist concentrations. These results reveal the presence of a Gads-independent pathway of platelet activation downstream of LAT.
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Affiliation(s)
- C E Hughes
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, Medical School, University of Birmingham, Birmingham, UK.
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Gonzalez-Espinosa C, Odom S, Olivera A, Hobson JP, Martinez MEC, Oliveira-Dos-Santos A, Barra L, Spiegel S, Penninger JM, Rivera J. Preferential signaling and induction of allergy-promoting lymphokines upon weak stimu lation of the high affinity IgE receptor on mast cells. J Exp Med 2003; 197:1453-65. [PMID: 12782712 PMCID: PMC2193904 DOI: 10.1084/jem.20021806] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2002] [Revised: 03/23/2003] [Accepted: 03/23/2003] [Indexed: 11/04/2022] Open
Abstract
Mast cell degranulation and de novo cytokine production is a consequence of antigen-aggregation of the immunoglobulin E (IgE)-occupied high affinity receptor for IgE (Fc epsilon RI). Herein, we report that lymphokines that promote allergic inflammation, like MCP-1, were potently induced at low antigen (Ag) concentrations or at low receptor occupancy with IgE whereas some that down-regulate this response, like interleukin (IL)-10, required high receptor occupancy. Weak stimulation of mast cells caused minimal degranulation whereas a half-maximal secretory response was observed for chemokines and, with the exception of TNF-alpha, a weaker cytokine secretory response was observed. The medium from weakly stimulated mast cells elicited a monocyte/macrophage chemotactic response similar to that observed at high receptor occupancy. Weak stimulation also favored the phosphorylation of Gab2 and p38MAPK, while LAT and ERK2 phosphorylation was induced by a stronger stimulus. Gab2-deficient mast cells were severely impaired in chemokine mRNA induction whereas LAT-deficient mast cells showed a more pronounced defect in cytokines. These findings demonstrate that perturbation of small numbers of IgE receptors on mast cells favors certain signals that contribute to a lymphokine response that can mediate allergic inflammation.
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Affiliation(s)
- Claudia Gonzalez-Espinosa
- Molecular Inflammation Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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8
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Judd BA, Myung PS, Obergfell A, Myers EE, Cheng AM, Watson SP, Pear WS, Allman D, Shattil SJ, Koretzky GA. Differential requirement for LAT and SLP-76 in GPVI versus T cell receptor signaling. J Exp Med 2002; 195:705-17. [PMID: 11901197 PMCID: PMC2193740 DOI: 10.1084/jem.20011583] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Mice deficient in the adaptor Src homology 2 domain-containing leukocyte phosphoprotein of 76 kD (SLP-76) exhibit a bleeding disorder and lack T cells. Linker for activation of T cells (LAT)-deficient mice exhibit a similar T cell phenotype, but show no signs of hemorrhage. Both SLP-76 and LAT are important for optimal platelet activation downstream of the collagen receptor, GPVI. In addition, SLP-76 is involved in signaling mediated by integrin alphaIIbbeta3. Because SLP-76 and LAT function coordinately in T cell signal transduction, yet their roles appear to differ in hemostasis, we investigated in detail the functional consequences of SLP-76 and LAT deficiencies in platelets. Previously we have shown that LAT(-/-) platelets exhibit defective responses to the GPVI-specific agonist, collagen-related peptide (CRP). Consistent with this, we find that surface expression of P-selectin in response to high concentrations of GPVI ligands is reduced in both LAT- and SLP-76-deficient platelets. However, platelets from LAT(-/-) mice, but not SLP-76(-/-) mice, aggregate normally in response to high concentrations of collagen and convulxin. Additionally, unlike SLP-76, LAT is not tyrosine phosphorylated after fibrinogen binding to integrin alphaIIbbeta3, and collagen-stimulated platelets deficient in LAT spread normally on fibrinogen-coated surfaces. Together, these findings indicate that while LAT and SLP-76 are equally required for signaling via the T cell antigen receptor (TCR) and pre-TCR, platelet activation downstream of GPVI and alphaIIbbeta3 shows a much greater dependency on SLP-76 than LAT.
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Affiliation(s)
- Barbi A Judd
- Program in Molecular Biology, University of Iowa, Iowa City, IA 52242, USA
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Abstract
Coreceptors CD28 and cytotoxic T lymphocyte antigen (CTLA)-4 have opposing effects on TcR/CD3 activation of T cells. While CD28 enhances and CTLA-4 inhibits activation, the underlying molecular basis of these effects has yet to be established. In this context, ganglioside and cholesterol enriched membrane microdomains (rafts, GEMs) serve as centers of signaling in T cells. Although CD28 can promote TcR/raft colocalization, evidence is lacking on whether the surface expression of membrane rafts can be targeted by CTLA-4 in its modulation of T cell responses. In this study, we demonstrate that both CD28 and CTLA-4 profoundly alter the surface expression of membrane rafts during T cell activation. While CD28 increased expression and the number of peripheral T cells induced to express surface rafts in response to TcR ligation, CTLA-4 potently inhibited both TcR and TcR x CD28 induced raft expression on the surface of T cells. Consistent with this, CD28 increased the presence of the linker of activated T cells (LAT) in purified membrane rafts, while CTLA-4 coligation effectively blocked this increase. Further, the reversal of the CTLA-4 block with CD3/CD28 ligation was accompanied by an increase in surface raft expression and associated LAT. Our observations demonstrate for the first time that CTLA-4 targets the release of rafts to the surface of T cells, and provides a mechanism for the opposing effects of CD28 and CTLA-4 on costimulation.
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Affiliation(s)
- M Martin
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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