1
|
Kashiwakura JI, Kawahara S, Inagaki I, Inui K, Saitoh K, Kagohashi K, Sasaki Y, Kobayashi F, Kitai Y, Muromoto R, Oritani K, Matsuda T. STAP-2 negatively regulates BCR-mediated B cell activation by recruiting tyrosine-protein kinase CSK to LYN. FEBS Lett 2023; 597:2433-2445. [PMID: 37669828 DOI: 10.1002/1873-3468.14730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 09/07/2023]
Abstract
Although signal-transducing adaptor protein-2 (STAP-2) acts in certain immune responses, its role in B cell receptor (BCR)-mediated signals remains unknown. In this study, we have revealed that BCR-mediated signals, cytokine production and antibody production were increased in STAP-2 knockout (KO) mice compared with wild-type (WT) mice. Phosphorylation of tyrosine-protein kinase LYN Y508 was reduced in STAP-2 KO B cells after BCR stimulation. Mechanistic analysis revealed that STAP-2 directly binds to LYN, dependently of STAP-2 Y250 phosphorylation by LYN. Furthermore, phosphorylation of STAP-2 enhanced interactions between LYN and tyrosine-protein kinase CSK, resulting in enhanced CSK-mediated LYN Y508 phosphorylation. These results suggest that STAP-2 is crucial for controlling BCR-mediated signals and antibody production by enhanced CSK-mediated feedback regulation of LYN.
Collapse
Affiliation(s)
- Jun-Ichi Kashiwakura
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
- Department of Life Science, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Hokkaido, Japan
| | - Shoya Kawahara
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Iori Inagaki
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kyosuke Inui
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kodai Saitoh
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kota Kagohashi
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yuto Sasaki
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Fuki Kobayashi
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yuichi Kitai
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ryuta Muromoto
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kenji Oritani
- Department of Hematology, International University of Health and Welfare, Narita, Chiba, Japan
| | - Tadashi Matsuda
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| |
Collapse
|
2
|
Characterization of Phosphorylation Status and Kinase Activity of Src Family Kinases Expressed in Cell-Based and Cell-Free Protein Expression Systems. Biomolecules 2021; 11:biom11101448. [PMID: 34680080 PMCID: PMC8533471 DOI: 10.3390/biom11101448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/27/2021] [Accepted: 09/30/2021] [Indexed: 11/25/2022] Open
Abstract
The production of heterologous proteins is an important procedure for biologists in basic and applied sciences. A variety of cell-based and cell-free protein expression systems are available to achieve this. The expression system must be selected carefully, especially for target proteins that require post-translational modifications. In this study, human Src family kinases were prepared using six different protein expression systems: 293 human embryonic kidney cells, Escherichia coli, and cell-free expression systems derived from rabbit reticulocytes, wheat germ, insect cells, or Escherichia coli. The phosphorylation status of each kinase was analyzed by Phos-tag SDS-PAGE. The kinase activities were also investigated. In the eukaryotic systems, multiple phosphorylated forms of the expressed kinases were observed. In the rabbit reticulocyte lysate system and 293 cells, differences in phosphorylation status between the wild-type and kinase-dead mutants were observed. Whether the expressed kinase was active depended on the properties of both the kinase and each expression system. In the prokaryotic systems, Src and Hck were expressed in autophosphorylated active forms. Clear differences in post-translational phosphorylation among the protein expression systems were revealed. These results provide useful information for preparing functional proteins regulated by phosphorylation.
Collapse
|
3
|
BAFF-driven NLRP3 inflammasome activation in B cells. Cell Death Dis 2020; 11:820. [PMID: 33004801 PMCID: PMC7529748 DOI: 10.1038/s41419-020-03035-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/14/2020] [Accepted: 09/16/2020] [Indexed: 02/06/2023]
Abstract
BAFF supports B-cell survival and homeostasis by activating the NF-κB pathway. While NF-κB is also involved in the priming signal of NLRP3 inflammasome, the role of BAFF in NLRP3 inflammasome regulation is unknown. Here we report BAFF engagement to BAFF receptor elicited both priming and activating signals for NLRP3 inflammasomes in primary B cells and B lymphoma cell lines. This induction of NLRP3 inflammasomes by BAFF led to increased NLRP3 and IL-1β expression, caspase-1 activation, IL-1β secretion, and pyroptosis. Mechanistically, BAFF activated NLRP3 inflammasomes by promoting the association of cIAP-TRAF2 with components of NLRP3 inflammasomes, and by inducing Src activity-dependent ROS production and potassium ion efflux. B-cell receptor (BCR) stimulation on the Lyn signaling pathway inhibited BAFF-induced Src activities and attenuated BAFF-induced NLRP3 inflammasome activation. These findings reveal an additional function of BAFF in B-cell homeostasis that is associated with BCR activities.
Collapse
|
4
|
Yamaga Y, Fukuda A, Nakanishi Y, Goto N, Matsumoto Y, Yoshioka T, Maruno T, Chiba T, Seno H. Gene expression profile of Dclk1 + cells in intestinal tumors. Dig Liver Dis 2018; 50:1353-1361. [PMID: 30001952 DOI: 10.1016/j.dld.2018.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND Accumulating evidence has shown the existence of tumor stem cells with therapeutic potential. Previously, we reported that doublecortin like kinase 1 (Dclk1) marks tumor stem cells but not normal stem cells in the intestine of ApcMin/+ mice, and that Dclk1- and Lgr5-double positive tumor cells are the tumor stem cells of intestinal tumors. AIM To investigate molecules highly expressed in the Dclk1+ normal intestinal and Dclk1+ tumor cells in ApcMin/+ mice. METHODS We used microarray analyses to examine the gene expression profile of Dclk1+ cells in both mouse normal intestinal epithelium and ApcMin/+ mouse intestinal tumors. We also performed immunofluorescence analyses. RESULTS Genes related to microtubules and the actin cytoskeleton (e.g., Rac2), and members of the Src family kinases (i.e., Hck, Lyn, Csk, and Ptpn6) were highly expressed in both Dclk1+ normal intestinal and Dclk1+ tumor cells. Phosphorylated Hck and phosphorylated Lyn were expressed in Lgr5+ cells in the intestinal tumors of Lgr5EGFP-IRES-CreERT2/+; ApcMin/+ mice. CONCLUSION We revealed factors that are highly expressed in Dclk1+ intestinal tumor cells, which may help to develop cancer stem cell-targeted therapy in future.
Collapse
Affiliation(s)
- Yuichi Yamaga
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Akihisa Fukuda
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yuki Nakanishi
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Norihiro Goto
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yoshihide Matsumoto
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takuto Yoshioka
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takahisa Maruno
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tsutomu Chiba
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hiroshi Seno
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| |
Collapse
|
5
|
Abstract
Targeted therapy of cancer typically focuses on inhibitors (for example, tyrosine kinase inhibitors) that suppress oncogenic signalling below a minimum threshold required for survival and proliferation of cancer cells. B cell acute lymphoblastic leukaemia and B cell lymphomas originate from various stages of development of B cells, which, unlike other cell types, are under intense selective pressure. The vast majority of newly generated B cells are autoreactive and die by negative selection at autoimmunity checkpoints (AICs). Owing to ubiquitous encounters with self-antigen, autoreactive B cells are eliminated by the overwhelming signalling strength of their autoreactive B cell receptor (BCR). A series of recent findings suggests that, despite malignant transformation, AICs are fully functional in B cell malignancies. This Opinion article proposes targeted engagement of AICs as a previously unrecognized therapeutic opportunity to overcome drug resistance in B cell malignancies.
Collapse
Affiliation(s)
- Markus Müschen
- Department of Systems Biology, Beckman Research Institute and National Cancer Institute (NCI) Comprehensive Cancer Center, City of Hope, Arcadia, California 91006, USA
| |
Collapse
|
6
|
Abstract
Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder that has a broad spectrum of effects on the majority of organs, including the kidneys. Approximately 40-70% of patients with SLE will develop lupus nephritis. Renal assault during SLE is initiated by genes that breach immune tolerance and promote autoantibody production. These genes might act in concert with other genetic factors that augment innate immune signalling and IFN-I production, which in turn can generate an influx of effector leucocytes, inflammatory mediators and autoantibodies into end organs, such as the kidneys. The presence of cognate antigens in the glomerular matrix, together with intrinsic molecular abnormalities in resident renal cells, might further accentuate disease progression. This Review discusses the genetic insights and molecular mechanisms for key pathogenic contributors in SLE and lupus nephritis. We have categorized the genes identified in human studies of SLE into one of four pathogenic events that lead to lupus nephritis. We selected these categories on the basis of the cell types in which these genes are expressed, and the emerging paradigms of SLE pathogenesis arising from murine models. Deciphering the molecular basis of SLE and/or lupus nephritis in each patient will help physicians to tailor specific therapies.
Collapse
|
7
|
Mahoney JM, Taroni J, Martyanov V, Wood TA, Greene CS, Pioli PA, Hinchcliff ME, Whitfield ML. Systems level analysis of systemic sclerosis shows a network of immune and profibrotic pathways connected with genetic polymorphisms. PLoS Comput Biol 2015; 11:e1004005. [PMID: 25569146 PMCID: PMC4288710 DOI: 10.1371/journal.pcbi.1004005] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 10/27/2014] [Indexed: 12/15/2022] Open
Abstract
Systemic sclerosis (SSc) is a rare systemic autoimmune disease characterized by skin and organ fibrosis. The pathogenesis of SSc and its progression are poorly understood. The SSc intrinsic gene expression subsets (inflammatory, fibroproliferative, normal-like, and limited) are observed in multiple clinical cohorts of patients with SSc. Analysis of longitudinal skin biopsies suggests that a patient's subset assignment is stable over 6-12 months. Genetically, SSc is multi-factorial with many genetic risk loci for SSc generally and for specific clinical manifestations. Here we identify the genes consistently associated with the intrinsic subsets across three independent cohorts, show the relationship between these genes using a gene-gene interaction network, and place the genetic risk loci in the context of the intrinsic subsets. To identify gene expression modules common to three independent datasets from three different clinical centers, we developed a consensus clustering procedure based on mutual information of partitions, an information theory concept, and performed a meta-analysis of these genome-wide gene expression datasets. We created a gene-gene interaction network of the conserved molecular features across the intrinsic subsets and analyzed their connections with SSc-associated genetic polymorphisms. The network is composed of distinct, but interconnected, components related to interferon activation, M2 macrophages, adaptive immunity, extracellular matrix remodeling, and cell proliferation. The network shows extensive connections between the inflammatory- and fibroproliferative-specific genes. The network also shows connections between these subset-specific genes and 30 SSc-associated polymorphic genes including STAT4, BLK, IRF7, NOTCH4, PLAUR, CSK, IRAK1, and several human leukocyte antigen (HLA) genes. Our analyses suggest that the gene expression changes underlying the SSc subsets may be long-lived, but mechanistically interconnected and related to a patients underlying genetic risk.
Collapse
Affiliation(s)
- J. Matthew Mahoney
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hannover, New Hampshire, United States of America
| | - Jaclyn Taroni
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hannover, New Hampshire, United States of America
| | - Viktor Martyanov
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hannover, New Hampshire, United States of America
| | - Tammara A. Wood
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hannover, New Hampshire, United States of America
| | - Casey S. Greene
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hannover, New Hampshire, United States of America
| | - Patricia A. Pioli
- Department of Obstetrics and Gynecology, Geisel School of Medicine at Dartmouth, Hannover, New Hampshire, United States of America
| | - Monique E. Hinchcliff
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Michael L. Whitfield
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hannover, New Hampshire, United States of America
| |
Collapse
|
8
|
Huber M, Gibbs BF. SHIP1 and the negative control of mast cell/basophil activation by supra-optimal antigen concentrations. Mol Immunol 2015; 63:32-7. [DOI: 10.1016/j.molimm.2014.02.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/19/2014] [Accepted: 02/25/2014] [Indexed: 10/25/2022]
|
9
|
Seda V, Mraz M. B-cell receptor signalling and its crosstalk with other pathways in normal and malignant cells. Eur J Haematol 2014; 94:193-205. [PMID: 25080849 DOI: 10.1111/ejh.12427] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2014] [Indexed: 12/13/2022]
Abstract
The physiology of B cells is intimately connected with the function of their B-cell receptor (BCR). B-cell lymphomas frequently (dys)regulate BCR signalling and thus take advantage of this pre-existing pathway for B-cell proliferation and survival. This has recently been underscored by clinical trials demonstrating that small molecules (fosfamatinib, ibrutinib, idelalisib) inhibiting BCR-associated kinases (SYK, BTK, PI3K) have an encouraging clinical effect. Here we describe the current knowledge of the specific aspects of BCR signalling in diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, chronic lymphocytic leukaemia (CLL) and normal B cells. Multiple factors can contribute to BCR pathway (dys)regulation in these malignancies and the activation of 'chronic' or 'tonic' BCR signalling. In lymphoma B cells, the balance of initiation, amplitude and duration of BCR activation can be influenced by a specific immunoglobulin structure, the expression and mutations of adaptor molecules (like GAB1, BLNK, GRB2, CARD11), the activity of kinases (like LYN, SYK, PI3K) or phosphatases (like SHIP-1, SHP-1 and PTEN) and levels of microRNAs. We also discuss the crosstalk of BCR with other signalling pathways (NF-κB, adhesion through integrins, migration and chemokine signalling) to emphasise that the 'BCR inhibitors' target multiple pathways interconnected with BCR, which might explain some of their clinical activity.
Collapse
Affiliation(s)
- Vaclav Seda
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | | |
Collapse
|
10
|
Abstract
Key Points
HS1 protein activation is differentially regulated by LYN kinase in CLL subsets. Dasatinib targets cytoskeletal activity, BCR signaling and survival of a sizable portion of patients with activated LYN/HS1.
Collapse
|
11
|
Xu Y, Huntington ND, Harder KW, Nandurkar H, Hibbs ML, Tarlinton DM. Phosphatidylinositol-3 kinase activity in B cells is negatively regulated by Lyn tyrosine kinase. Immunol Cell Biol 2012; 90:903-11. [PMID: 22777522 DOI: 10.1038/icb.2012.31] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phosphatidylinositol-3 kinase (PI3K) activity is essential for normal B-cell receptor (BCR)-mediated responses. To understand the mechanisms of PI3K regulation during B-cell activation, we performed a series of biochemical analysis on primary B cells, and found that activity of Src family tyrosine kinases (SFK) is crucial for the activation of PI3K following BCR ligation and this is regulated by the SFK Lyn. We show that the hyperresponsive phenotype of B cells lacking Lyn is predicated on significantly increased basal and inducible PI3K activity that correlates with the constitutive hypophosphorylation of PAG/Cbp (phosphoprotein associated with glycosphingolipid-enriched microdomains/Csk-binding protein), a concomitant reduction in bound Csk in Lyn(-/-) B cells and elevated levels of active Fyn. Regulating SFK activity may thus be a central mechanism by which Lyn regulates PI3K activity in B cells. This study defines the molecular connection between the BCR and PI3K and reveals this to be a point of Lyn-mediated regulation.
Collapse
Affiliation(s)
- Yuekang Xu
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | | | | | | | | | | |
Collapse
|
12
|
Barua D, Hlavacek WS, Lipniacki T. A computational model for early events in B cell antigen receptor signaling: analysis of the roles of Lyn and Fyn. THE JOURNAL OF IMMUNOLOGY 2012; 189:646-58. [PMID: 22711887 DOI: 10.4049/jimmunol.1102003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BCR signaling regulates the activities and fates of B cells. BCR signaling encompasses two feedback loops emanating from Lyn and Fyn, which are Src family protein tyrosine kinases (SFKs). Positive feedback arises from SFK-mediated trans phosphorylation of BCR and receptor-bound Lyn and Fyn, which increases the kinase activities of Lyn and Fyn. Negative feedback arises from SFK-mediated cis phosphorylation of the transmembrane adapter protein PAG1, which recruits the cytosolic protein tyrosine kinase Csk to the plasma membrane, where it acts to decrease the kinase activities of Lyn and Fyn. To study the effects of the positive and negative feedback loops on the dynamical stability of BCR signaling and the relative contributions of Lyn and Fyn to BCR signaling, we consider in this study a rule-based model for early events in BCR signaling that encompasses membrane-proximal interactions of six proteins, as follows: BCR, Lyn, Fyn, Csk, PAG1, and Syk, a cytosolic protein tyrosine kinase that is activated as a result of SFK-mediated phosphorylation of BCR. The model is consistent with known effects of Lyn and Fyn deletions. We find that BCR signaling can generate a single pulse or oscillations of Syk activation depending on the strength of Ag signal and the relative levels of Lyn and Fyn. We also show that bistability can arise in Lyn- or Csk-deficient cells.
Collapse
Affiliation(s)
- Dipak Barua
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | | | | |
Collapse
|
13
|
Dong Z, Davidson D, Pérez-Quintero LA, Kurosaki T, Swat W, Veillette A. The adaptor SAP controls NK cell activation by regulating the enzymes Vav-1 and SHIP-1 and by enhancing conjugates with target cells. Immunity 2012; 36:974-85. [PMID: 22683124 DOI: 10.1016/j.immuni.2012.03.023] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/31/2012] [Accepted: 03/23/2012] [Indexed: 11/29/2022]
Abstract
The adaptor SAP, mutated in X-linked lymphoproliferative disease, has critical roles in multiple immune cell types. Among these, SAP is essential for the ability of natural killer (NK) cells to eliminate abnormal hematopoietic cells. Herein, we elucidated the molecular and cellular bases of this activity. SAP enhanced NK cell responsiveness by a dual molecular mechanism. It coupled SLAM family receptors to the kinase Fyn, which triggered the exchange factor Vav-1 and augmented NK cell activation. SAP also prevented the inhibitory function of SLAM family receptors. This effect was Fyn independent and correlated with uncoupling of SLAM family receptors from the lipid phosphatase SHIP-1. Both mechanisms cooperated to enable conjugate formation with target cells and to stimulate cytotoxicity and cytokine secretion by NK cells. These data showed that SAP secures NK cell activation by a dichotomous molecular mechanism, which is required for conjugate formation. These findings may have implications for the role of SAP in other immune cell types.
Collapse
Affiliation(s)
- Zhongjun Dong
- Laboratory of Molecular Oncology, Clinical Research Institute of Montréal, Montréal, Québec, Canada.
| | | | | | | | | | | |
Collapse
|
14
|
Tavolaro S, Chiaretti S, Messina M, Peragine N, Del Giudice I, Marinelli M, Santangelo S, Mauro FR, Guarini A, Foà R. Gene expression profile of protein kinases reveals a distinctive signature in chronic lymphocytic leukemia and in vitro experiments support a role of second generation protein kinase inhibitors. Leuk Res 2010; 34:733-41. [DOI: 10.1016/j.leukres.2009.11.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 11/03/2009] [Accepted: 11/05/2009] [Indexed: 12/30/2022]
|
15
|
Abstract
B-lymphoid kinase (Blk) is exclusively expressed in B cells and thymocytes. Interestingly, transgenic expression of a constitutively active form of Blk in the T-cell lineage of mice results in the development of T-lymphoid lymphomas. Here, we demonstrate nuclear factor-kappa B (NF-kappaB)-mediated ectopic expression of Blk in malignant T-cell lines established from patients with cutaneous T-cell lymphoma (CTCL). Importantly, Blk is also expressed in situ in lesional tissue specimens from 26 of 31 patients with CTCL. Already in early disease the majority of epidermotropic T cells express Blk, whereas Blk expression is not observed in patients with benign inflammatory skin disorders. In a longitudinal study of an additional 24 patients biopsied for suspected CTCL, Blk expression significantly correlated with a subsequently confirmed diagnosis of CTCL. Blk is constitutively tyrosine phosphorylated in malignant CTCL cell lines and spontaneously active in kinase assays. Furthermore, targeting Blk activity and expression by Src kinase inhibitors and small interfering RNA (siRNA) inhibit the proliferation of the malignant T cells. In conclusion, this is the first report of Blk expression in CTCL, thereby providing new clues to the pathogenesis of the disease.
Collapse
|
16
|
|
17
|
Grande SM, Bannish G, Fuentes-Panana EM, Katz E, Monroe JG. Tonic B-cell and viral ITAM signaling: context is everything. Immunol Rev 2007; 218:214-34. [PMID: 17624955 DOI: 10.1111/j.1600-065x.2007.00535.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The presence of an immunoreceptor tyrosine-based activation motif (ITAM) makes immunoreceptors different from other signaling receptors, like integrins, G-coupled protein receptors, chemokine receptors, and growth factor receptors. This unique motif has the canonical sequence D/Ex(0-2)YxxL/Ix(6-8)YxxL/I, where x represents any amino acid and is present at least once in all immunoreceptor complexes. Immunoreceptors can promote survival, activation, and differentiation by transducing signals through these highly conserved motifs. Traditionally, ITAM signaling is thought to occur in response to ligand-induced aggregation, although evidence indicates that ligand-independent tonic signaling also provides functionally relevant signals. The majority of proteins containing ITAMs are transmembrane proteins that exist as part of immunoreceptor complexes. However, oncogenic viruses also have ITAM-containing proteins. In this review, we discuss what is known about tonic signaling by both cellular and viral ITAM-containing proteins and speculate what we might learn from each context.
Collapse
Affiliation(s)
- Shannon M Grande
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | | |
Collapse
|
18
|
Abstract
The type I Fc epsilon receptor (Fc epsilon RI) is one of the better understood members of its class and is central to the immunological activation of mast cells and basophils, the key players in immunoglobulin E (IgE)-dependent immediate hypersensitivity. This review provides background information on several distinct regulatory mechanisms controlling this receptor's stimulus-response coupling network. First, we review the current understanding of this network's operation, and then we focus on the inhibitory regulatory mechanisms. In particular, we discuss the different known cytosolic molecules (e.g. kinases, phosphatases, and adapters) as well as cell membrane proteins involved in negatively regulating the Fc epsilon RI-induced secretory responses. Knowledge of this field is developing at a fast rate, as new proteins endowed with regulatory functions are still being discovered. Our understanding of the complex networks by which these proteins exert regulation is limited. Although the scope of this review does not include addressing several important biochemical and biophysical aspects of the regulatory mechanisms, it does provide general insights into a central field in immunology.
Collapse
Affiliation(s)
- Jakub Abramson
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | | |
Collapse
|
19
|
Achiwa H, Lazo JS. PRL-1 Tyrosine Phosphatase Regulates c-Src Levels, Adherence, and Invasion in Human Lung Cancer Cells. Cancer Res 2007; 67:643-50. [PMID: 17234774 DOI: 10.1158/0008-5472.can-06-2436] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phosphatases of regenerating liver (PRL) constitute a subfamily of the protein tyrosine phosphatases that are implicated in oncogenic and metastatic phenotypes. In this study, we evaluated the role of PRL-1 in cell proliferation and metastatic processes in human lung cancer cells. We stably transfected human A549 lung cancer cells with several short hairpin RNAs for PRL-1 and found decreased invasive activity in the resulting clones compared with control cells. In addition, cells with suppressed PRL-1 exhibited greater adherence and cell spreading on fibronectin and a decreased proliferation rate compared with control cells. To address possible mechanisms for the altered phenotypes, we examined known biochemical regulators of adhesion and invasion. Inhibition of PRL-1 decreased c-Src and p130Cas expression and Rac1 and Cdc42 activation without any apparent modification of focal adhesion kinase (FAK) expression. Total tyrosine FAK phosphorylation and Tyr397 phosphorylation levels were continuously elevated in PRL-1 knockdown cells plated on fibronectin. In immunofluorescence studies, reduction in PRL-1 seemed to decrease cell membrane protrusions with a reduction in actin fiber extensions in spite of continuous phosphorylation of Tyr397 FAK, which could reflect reduced adhesion turnover. Our data implicate PRL-1 in the fundamental process of cell adhesion and migration in human lung cancer cells by affecting Rac1, Cdc42, and c-Src activation. These results support the hypothesis that PRL-1 plays an important role in maintaining the malignant phenotype by exploiting Src activation processes, and that PRL-1 could be a promising therapeutic target for cancer metastasis and cell growth.
Collapse
Affiliation(s)
- Hiroyuki Achiwa
- Department of Pharmacology, Drug Discovery Institute, and University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | | |
Collapse
|
20
|
Daoud G, Rassart E, Masse A, Lafond J. Src family kinases play multiple roles in differentiation of trophoblasts from human term placenta. J Physiol 2006; 571:537-53. [PMID: 16410281 PMCID: PMC1805791 DOI: 10.1113/jphysiol.2005.102285] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Tyrosine phosphorylation plays a major role in controlling many biological processes in different cell types. Src family kinases (SFKs) are one of the most studied groups of tyrosine kinases and can mediate a variety of signalling pathways. However, little is known about the expression of SFKs in human term placenta and their implication in trophoblast differentiation. Therefore, we examined the expression profile of SFK members over time in culture and their implication in differentiation. In vitro, freshly isolated cytotrophoblast cells, cultured in 10% fetal bovine serum (FBS), spontaneously aggregate and fuse to form multinucleated cells that resemble phenotypically mature syncytiotrophoblasts, that concomitantly produce human chorionic gonadotropin (hCG) and human placental lactogen (hPL). In this study, we showed that trophoblasts expressed all SFK members and some of them are expressed as different splice variants. Moreover, using real-time PCR, this study showed two different expression profiles of SFKs in human trophoblasts during culture. In addition, the protein level and phosphorylation status of Src were evaluated using specific antibodies. Src was rapidly phosphorylated at Tyr-416 and dephosphorylated at Tyr-527 after FBS addition. Surprisingly, inhibition of SFKs by 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d] pyrimidine (PP2) or herbimycin A had different effects on trophoblast differentiation. While herbimycin A inhibited morphological and hormonal differentiation, PP2 stimulated hormonal differentiation and inhibited cell adhesion and spreading with no effect on cell fusion. In summary, this study showed that SFKs play different roles in trophoblast differentiation, probably depending on SFK members activated. Thus, this study increases our knowledge and understanding of pathology related to impaired trophoblast differentiation such as pre-eclampsia and trophoblast neoplasm.
Collapse
Affiliation(s)
- Georges Daoud
- Laboratoire de Physiologie materno-foetale, Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montréal, Canada, H3C 3P8
| | | | | | | |
Collapse
|
21
|
Chong YP, Mulhern TD, Cheng HC. C-terminal Src kinase (CSK) and CSK-homologous kinase (CHK)--endogenous negative regulators of Src-family protein kinases. Growth Factors 2005; 23:233-44. [PMID: 16243715 DOI: 10.1080/08977190500178877] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
C-terminal Src kinase (CSK) and CSK-homologous kinase (CHK) are endogenous inhibitors of the Src-family protein tyrosine kinases (SFKs). Since constitutive activation of SFKs contributes to cancer formation and progression, to prevent excessive activation of SFKs, their activity in normal cells is kept at the basal level by CSK and CHK. CSK and CHK inactivate SFKs by specifically phosphorylating a consensus tyrosine (called Y(T)) near their C-termini. Upon phosphorylation, the phospho-Y(T) engages in intramolecular interactions that lock the SFK molecule in an inactive conformation. SFKs are anchored to the plasma membrane, while CSK and CHK are localized predominantly in the cytosol. To inhibit SFKs, CSK and CHK need to translocate to the plasma membrane. Recruitment of CSK and CHK to the plasma membrane is mediated by the binding of their SH2, SH3 and/or kinase domains to specific transmembrane proteins, G-proteins and adaptor proteins located near the plasma membrane. For CSK, membrane recruitment often accompanies activation. CSK and CHK employ two types of direct interactions with SFKs to achieve efficient Y(T) phosphorylation: (i) short-range interactions involving binding of the active sites of CSK and CHK to specific residues near Y(T), (ii) long-range non-catalytic interactions involving binding of SFKs to motifs located distally from the active sites of CSK and CHK. The interactions between CSK and SFKs are transient in nature. Unlike CSK, CHK binds tightly to SFKs to form stable protein complexes. The binding is non-catalytic as it is independent of Y(T). More importantly, the tight binding alone is sufficient to completely inhibit SFKs. This non-catalytic inhibitory binding represents a novel mechanism employed by CHK to inhibit SFKs. Given that SFKs are implicated in cancer development, compounds mimicking the non-catalytic inhibitory mechanism of CHK are potential anti-cancer therapeutics.
Collapse
Affiliation(s)
- Yuh-Ping Chong
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Department of Biochemistry and Molecular Biology, Parkville, Victoria, Australia
| | | | | |
Collapse
|
22
|
Xu Y, Harder KW, Huntington ND, Hibbs ML, Tarlinton DM. Lyn tyrosine kinase: accentuating the positive and the negative. Immunity 2005; 22:9-18. [PMID: 15664155 DOI: 10.1016/j.immuni.2004.12.004] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 12/29/2004] [Accepted: 12/30/2004] [Indexed: 12/21/2022]
Abstract
Lyn, one of several Src-family tyrosine kinases in immune cells, is noted for its ability to negatively regulate signaling pathways through phosphorylation of inhibitory receptors, enzymes, and adaptors. Somewhat paradoxically, it is also a key mediator in several pathways of B cell activation, such as CD19 and CD180. Whether Lyn functions to promote or inhibit immune cell activation depends on the stimulus and the developmental state, meaning that the consequences of Lyn activity are context dependent. The importance of regulating Lyn activity is exemplified by the pathological conditions that develop in both lyn-/- and lyn gain-of-function mice (lynup/up), including lethal antibody-mediated autoimmune diseases and myeloid neoplasia. Here, we review the outcomes of altered Lyn activity within the framework of B cell development and differentiation and the circumstances that appear to dictate the outcome.
Collapse
Affiliation(s)
- Yuekang Xu
- The Walter and Eliza Hall Institute of Medical Research, Melbourne 3050, Australia
| | | | | | | | | |
Collapse
|
23
|
Yamazoe M, Sonoda E, Hochegger H, Takeda S. Reverse genetic studies of the DNA damage response in the chicken B lymphocyte line DT40. DNA Repair (Amst) 2004; 3:1175-85. [PMID: 15279806 DOI: 10.1016/j.dnarep.2004.03.039] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the 'post-genome' era, reverse genetics is one of the most informative and powerful means to investigate protein function. The chicken B lymphocyte line DT40 is widely used for reverse genetics because the cells have a number of advantages, including efficient gene targeting as well as a remarkably stable phenotype. Furthermore, the absence of functional p53 in DT40 cells enables identification of DNA damage using chromosome analysis by suppressing damage-induced apoptosis during interphase. This review summarizes the contribution of DT40 cells to reverse genetic studies of DNA damage response pathways in higher eukaryotic cells.
Collapse
Affiliation(s)
- Mitsuyoshi Yamazoe
- CRESTO, The Japan Science and Technology Corporation, Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | | | | | | |
Collapse
|
24
|
Young RM, Holowka D, Baird B. A lipid raft environment enhances Lyn kinase activity by protecting the active site tyrosine from dephosphorylation. J Biol Chem 2003; 278:20746-52. [PMID: 12670955 DOI: 10.1074/jbc.m211402200] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The plasma membrane contains ordered lipid domains, commonly called lipid rafts, enriched in cholesterol, sphingolipids, and certain signaling proteins. Lipid rafts play a structural role in signal initiation by the high affinity receptor for IgE. Cross-linking of IgE-receptor complexes by antigen causes their coalescence with lipid rafts, where they are phosphorylated by the Src family tyrosine kinase, Lyn. To understand how lipid rafts participate in functional coupling between Lyn and FcepsilonRI, we investigated whether the lipid raft environment influences the specific activity of Lyn. We used differential detergent solubility and sucrose gradient fractionation to isolate Lyn from raft and nonraft regions of the plasma membrane in the presence or absence of tyrosine phosphatase inhibitors. We show that Lyn recovered from lipid rafts has a substantially higher specific activity than Lyn from nonraft environments. Furthermore, this higher specific activity correlates with increased tyrosine phosphorylation at the active site loop of the kinase domain. Based on these results, we propose that lipid rafts exclude a phosphatase that negatively regulates Lyn kinase activity by constitutive dephosphorylation of the kinase domain tyrosine residue of Lyn. In this model, cross-linking of FcepsilonRI promotes its proximity to active Lyn in a lipid raft environment.
Collapse
Affiliation(s)
- Ryan M Young
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | | | | |
Collapse
|
25
|
Zhu DM, Tibbles HE, Vassilev AO, Uckun FM. SYK and LYN mediate B-cell receptor-independent calcium-induced apoptosis in DT-40 lymphoma B-cells. Leuk Lymphoma 2002; 43:2165-70. [PMID: 12533043 DOI: 10.1080/1042819021000032935] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Here, we report that the calcium ionophore ionomycin induces a massive Ca2+-dependent apoptosis in wildtype DT-40 chicken B lymphoma cells, as well as in BTK-deficient, PLCgamma2-deficient and IP3 receptor-deficient DT-40 cells, but not in LYN- or SYK-deficient DT-40 cells. Notably, the deficiency of CSK, a negative regulator of Src-family PTK, promoted ionomycin-induced apoptosis of DT-40 cells. Reconstitution of SYK-deficient cells with wild-type SYK restored the apoptotic response of the cells to ionomycin, but the expression of FYN or LCK in LYN-deficient cells did not restore the apoptotic response of LYN-deficient cells. Taken together, our data suggests that both LYN and SYK, but not BTK, FYN or LCK, are crucial mediators of BCR-independent Ca2+-induced apoptosis in DT-40 lymphoma B cells.
Collapse
Affiliation(s)
- De-Min Zhu
- Department of Immunology, Parker Hughes Cancer Center Parker Hughes Institute, 2669 Patton Road, Roseville, St. Paul, MN 55113, USA
| | | | | | | |
Collapse
|
26
|
Abstract
Immune cells are activated as a result of productive interactions between ligands and various receptors known as immunoreceptors. These receptors function by recruiting cytoplasmic protein tyrosine kinases, which trigger a unique phosphorylation signal leading to cell activation. In the recent past, there has been increasing interest in elucidating the processes involved in the negative regulation of immunoreceptor-mediated signal transduction. Evidence is accumulating that immunoreceptor signaling is inhibited by complex and highly regulated mechanisms that involve receptors, protein tyrosine kinases, protein tyrosine phosphatases, lipid phosphatases, ubiquitin ligases, and inhibitory adaptor molecules. Genetic evidence indicates that this inhibitory machinery is crucial for normal immune cell homeostasis.
Collapse
Affiliation(s)
- André Veillette
- Laboratory of Molecular Oncology, IRCM, 110 Pine Avenue West, Montréal, Québec, Canada H2W 1R7.
| | | | | |
Collapse
|
27
|
Abstract
An important role has emerged for adaptor molecules in linking cell-surface receptors, such as the B-cell antigen receptor, with effector enzymes. Adaptor proteins direct the appropriate subcellular localization of effectors and regulate their activity by inducing conformational changes, both of which, in turn, contribute to the spatio-temporal precision of B-cell signal-transduction events. In addition, adaptor molecules participate in establishing negative- or positive-feedback regulatory loops in signalling networks, thereby fine-tuning the B-cell response.
Collapse
Affiliation(s)
- Tomohiro Kurosaki
- Department of Molecular Genetics, Institute for Liver Research, Kansai Medical University, Japan.
| |
Collapse
|
28
|
Cheng PC, Brown BK, Song W, Pierce SK. Translocation of the B cell antigen receptor into lipid rafts reveals a novel step in signaling. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:3693-701. [PMID: 11238609 DOI: 10.4049/jimmunol.166.6.3693] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The cross-linking of the B cell Ag receptor (BCR) leads to the initiation of a signal transduction cascade in which the earliest events involve the phosphorylation of the immunoreceptor tyrosine-based activation motifs of Ig alpha and Ig beta by the Src family kinase Lyn and association of the BCR with the actin cytoskeleton. However, the mechanism by which BCR cross-linking initiates the cascade remains obscure. In this study, using various A20-transfected cell lines, biochemical and genetic evidence is provided that BCR cross-linking leads to the translocation of the BCR into cholesterol- and sphingolipid-rich lipid rafts in a process that is independent of the initiation of BCR signaling and does not require the actin cytoskeleton. Translocation of the BCR into lipid rafts did not require the Ig alpha/Ig beta signaling complex, was not dependent on engagement of the FcR, and was not blocked by the Src family kinase inhibitor PP2 or the actin-depolymerizing agents cytochalasin D or latrunculin. Thus, cross-linking or oligomerization of the BCR induces the BCR translocation into lipid rafts, defining an event in B cell activation that precedes receptor phosphorylation and association with the actin cytoskeleton.
Collapse
MESH Headings
- Actins/metabolism
- Animals
- Antigens, CD/genetics
- Biological Transport, Active/genetics
- Biological Transport, Active/immunology
- CD79 Antigens
- Cell Membrane/enzymology
- Cell Membrane/genetics
- Cell Membrane/immunology
- Cytoskeleton/metabolism
- Enzyme Activation/immunology
- Humans
- Immunoglobulin mu-Chains/genetics
- Membrane Microdomains/enzymology
- Membrane Microdomains/immunology
- Membrane Microdomains/metabolism
- Mice
- Mutagenesis, Site-Directed
- Phosphorylation
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, B-Cell/physiology
- Receptors, IgG/metabolism
- Signal Transduction/genetics
- Signal Transduction/immunology
- Temperature
- Tumor Cells, Cultured
- Tyrosine/metabolism
- src-Family Kinases/metabolism
Collapse
Affiliation(s)
- P C Cheng
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208, USA
| | | | | | | |
Collapse
|
29
|
Winding P, Berchtold MW. The chicken B cell line DT40: a novel tool for gene disruption experiments. J Immunol Methods 2001; 249:1-16. [PMID: 11226459 DOI: 10.1016/s0022-1759(00)00333-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The use of the chicken DT40 B cell line is increasing in popularity due to the ease with which it can be manipulated genetically. It offers a targeted to random DNA integration ratio of more than 1:2, by far exceeding that of any mammalian cell line. The facility with which knockout cell lines can be generated, combined with a short generation time, makes the DT40 cell line attractive for phenotype analysis of single and multiple gene disruptions. Advantage has been taken of this to investigate such diverse fields as B cell antigen receptor (BCR) signaling, cell cycle regulation, gene conversion and apoptosis. In this review, we give a historical introduction and a practical guide to the use of the DT40 cell line, along with an overview of the main topics being researched using the DT40 cell line as a model system. These topics include B cell-specific subjects such as B cell signaling and Ig rearrangement, and subjects common to all cell types such as apoptosis, histones, mRNA modification, chromosomal maintenance and DNA repair. Attention is in each case brought to peculiarities of the DT40 cell line that are of relevance for the subject. Novel applications of the cell line, e.g., as a vector for gene targeting of human chromosomes, are also discussed in this review.
Collapse
Affiliation(s)
- P Winding
- Institute of Molecular Biology, Oster Farimagsgade 2A, DK-1353, K, Copenhagen, Denmark
| | | |
Collapse
|
30
|
Hsueh RC, Scheuermann RH. Tyrosine kinase activation in the decision between growth, differentiation, and death responses initiated from the B cell antigen receptor. Adv Immunol 2001; 75:283-316. [PMID: 10879287 DOI: 10.1016/s0065-2776(00)75007-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Immunoglobulin-containing receptors expressed on B lineage lymphocytes play critical roles in the development and function of the humoral arm of the immune system. The preB cell antigen receptor (preBCR) contains the immunoglobulin mu heavy chain (Ig mu) and signals to the preB cell that heavy chain rearrangement has been successful, a process termed heavy chain selection. The B cell antigen receptor (BCR) contains both Ig heavy and light chains and is expressed on immature and mature B cells before and after antigen encounter. Both receptor types from a complex with the Ig alpha and Ig beta proteins that link the predominantly extracellular Ig with intracellular signal transduction pathways. Signaling through the BCR induces different cellular responses depending on the nature of the signaling agent and the development stage of the target cell. These responses include clonal anergy and apoptotic deletion in immature B cells and survival, proliferation, and differentiation in mature B and preB cells. Several protein tyrosine kinases are activated rapidly following engagement of the BCR/preBCR complexes, including members of the Src family (Lyn and Blk), the Syk/ZAP70 family (Syk), and the Tec family (Btk). In this review, we discuss possible mechanisms by which engagement of these similar receptor complexes can give rise to different cellular responses and the role that these kinases play in this process.
Collapse
MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Antibody Formation
- Antigens, CD/genetics
- Antigens, CD/immunology
- Apoptosis/physiology
- B-Lymphocyte Subsets/cytology
- B-Lymphocyte Subsets/enzymology
- B-Lymphocyte Subsets/immunology
- CD79 Antigens
- Cell Differentiation/physiology
- Cell Division/physiology
- Enzyme Activation
- Enzyme Precursors/physiology
- Genes, Immunoglobulin
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/immunology
- Humans
- Immune Tolerance
- Immunoglobulin Heavy Chains/genetics
- Immunologic Deficiency Syndromes/enzymology
- Immunologic Deficiency Syndromes/genetics
- Immunologic Deficiency Syndromes/immunology
- Intracellular Signaling Peptides and Proteins
- Lymphocyte Activation
- Phosphorylation
- Plasma Cells/cytology
- Plasma Cells/immunology
- Protein Processing, Post-Translational
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/physiology
- Recombinant Fusion Proteins/immunology
- Signal Transduction
- Syk Kinase
- ZAP-70 Protein-Tyrosine Kinase
- src Homology Domains
- src-Family Kinases/deficiency
- src-Family Kinases/genetics
- src-Family Kinases/physiology
Collapse
Affiliation(s)
- R C Hsueh
- Laboratory of Molecular Pathology, University of Texas Southwestern Medical Center, Dallas 75235, USA
| | | |
Collapse
|
31
|
Tyan ML. Effects of inositol, LiCl, and heparin on the antibody responses to SRBC by normal and immunodeficient XID mice. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 2000; 224:187-90. [PMID: 10865235 DOI: 10.1046/j.1525-1373.2000.22419.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Spleen cells from naïve adult immunocompetent and immunodeficient XID mice were cultured on agar containing sheep red blood cells (SRBC) with and without myo-inositol, scyllo-inositol, lithium chloride, or heparin, and after 1 or 2 days the number of colonies of antiSRBC antibody-forming cells (PFC) were determined. It was found that myo-inositol and scyllo-inositol at one-tenth the concentration were equally effective in increasing the number of specific PFC. Myo-inositol, scyllo-inositol, and lithium chloride accelerated the appearance of direct foci in cultures of spleen cells from normal and XID mice. When heparin was added to cultures of XID spleen cells, PFC were found to be increased on Day 1; however, PFC and foci were not increased in cultures of spleen cells from competent mice until 1 day later. The addition of combinations of these agents to cultures of spleen cells had no positive or negative effect on the generation of foci or PFC. Normal mice given heparin intraperitoneally with SRBC had increased splenic PFC on Days 3 and 4 but not on Day 7. The results suggest that these agents modulate B-cell responses by increasing the rate of proliferation and/or secretion through a signaling pathway(s) distal to, or more likely, independent of Bruton's tyrosine Kinase (BTK). It is not clear that the mechanism is the same with each agent.
Collapse
Affiliation(s)
- M L Tyan
- West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA 90073, USA. tyan.marvin_1+@west_la.va.gov
| |
Collapse
|
32
|
Wienands J. The B-cell antigen receptor: formation of signaling complexes and the function of adaptor proteins. Curr Top Microbiol Immunol 1999; 245:53-76. [PMID: 10533310 DOI: 10.1007/978-3-642-57066-7_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- J Wienands
- Department for Molecular Immunology, Biology III, University of Freiburg, Germany.
| |
Collapse
|
33
|
Abstract
In B lymphocytes, a signaling complex that contributes to cell fate decisions is the B cell antigen receptor (BCR). Data from knockout experiments in cell lines and mice have revealed distinct functions for the intracellular protein tyrosine kinases (Lyn, Syk, Btk) in BCR signaling and B cell development. Combinations of intracellular signaling pathways downstream of these PTKs determine the quality and quantity of BCR signaling. For example, concerted actions of the PLC-gamma 2 and PI3-K pathways are required for proper calcium responses. Similarly, the regulation of ERK and JNK responses involves both PLC-gamma 2 and GTPases pathways. Since the immune response in vivo is regulated by alteration of these signaling outcomes, achieving a precise understanding of intracellular molecular events leading to B lymphocyte proliferation, deletion, anergy, receptor editing, and survival still remains a challenge for the future.
Collapse
Affiliation(s)
- T Kurosaki
- Department of Molecular Genetics, Kansai Medical University, Moriguchi, Japan.
| |
Collapse
|
34
|
Gergely J, Pecht I, Sármay G. Immunoreceptor tyrosine-based inhibition motif-bearing receptors regulate the immunoreceptor tyrosine-based activation motif-induced activation of immune competent cells. Immunol Lett 1999; 68:3-15. [PMID: 10397150 DOI: 10.1016/s0165-2478(99)00024-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ITIM-bearing receptors, a family which only recently has been recognized, play a key role in the regulation of the ITAM-induced activation of immune competent cells. The mechanism of ITM-mediated regulation in various cells was recently clarified. The present review focuses on ITIM bearing membrane proteins that negatively regulate the activation of cells when co-crosslinked with ITAM containing receptors, illustrates the inhibitory processes by the negative regulation of B-, NK-, T-cells and mast cells and summarizes current views on the mechanism of ITIM-mediated inhibition.
Collapse
Affiliation(s)
- J Gergely
- Research Group of the Hungarian Academy of Science at the Department of Immunology, Eötvös Loránd University, Göd
| | | | | |
Collapse
|
35
|
Zou Y, Komuro I, Yamazaki T, Kudoh S, Uozumi H, Kadowaki T, Yazaki Y. Both Gs and Gi proteins are critically involved in isoproterenol-induced cardiomyocyte hypertrophy. J Biol Chem 1999; 274:9760-70. [PMID: 10092665 DOI: 10.1074/jbc.274.14.9760] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of beta-adrenoreceptors induces cardiomyocyte hypertrophy. In the present study, we examined isoproterenol-evoked intracellular signal transduction pathways leading to activation of extracellular signal-regulated kinases (ERKs) and cardiomyocyte hypertrophy. Inhibitors for cAMP and protein kinase A (PKA) abolished isoproterenol-evoked ERK activation, suggesting that Gs protein is involved in the activation. Inhibition of Gi protein by pertussis toxin, however, also suppressed isoproterenol-induced ERK activation. Overexpression of the Gbetagamma subunit binding domain of the beta-adrenoreceptor kinase 1 and of COOH-terminal Src kinase, which inhibit functions of Gbetagamma and the Src family tyrosine kinases, respectively, also inhibited isoproterenol-induced ERK activation. Overexpression of dominant-negative mutants of Ras and Raf-1 kinase and of the beta-adrenoreceptor mutant that lacks phosphorylation sites by PKA abolished isoproterenol-stimulated ERK activation. The isoproterenol-induced increase in protein synthesis was also suppressed by inhibitors for PKA, Gi, tyrosine kinases, or Ras. These results suggest that isoproterenol induces ERK activation and cardiomyocyte hypertrophy through two different G proteins, Gs and Gi. cAMP-dependent PKA activation through Gs may phosphorylate the beta-adrenoreceptor, leading to coupling of the receptor from Gs to Gi. Activation of Gi activates ERKs through Gbetagamma, Src family tyrosine kinases, Ras, and Raf-1 kinase.
Collapse
Affiliation(s)
- Y Zou
- Department of Cardiovascular Medicine, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113 8655, Japan
| | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
The avian DT40 cell system represents a novel method to generate loss of function mutations in vertebrate cells. These chicken B lymphoma cells undergo homologous recombination at very high frequencies and can thus be used to "knock out" genes believed to function in apoptotic processes. The knockout cells can then be used to determine how the cell death process is modulated after induction of apoptosis and to order components in cell death pathways. The system can be further modified, using tetracycline-responsive promoters, to allow expression of wild-type cDNAs to rescue "knockout cells" if the gene of interest is essential. Alternatively, cDNA expression constructs containing mutations or deletions in the cDNA encoding the absent protein can be used to delineate functional domains. cDNA expression libraries or known proteins believed to function downstream of the target in a signal transduction pathway could also be transfected into the knockout cell line, and the resultant cells could be assayed for complementation and/or rescue of the apoptotic alteration/defect. Finally, the system has recently been adapted to allow disruption of human genes in DT40/human hybrid cell lines thereby potentially extending this system for use in studying human genes.
Collapse
Affiliation(s)
- J M Lahti
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, Tennessee 38105, USA.
| |
Collapse
|
37
|
Aikawa R, Komuro I, Yamazaki T, Zou Y, Kudoh S, Zhu W, Kadowaki T, Yazaki Y. Rho family small G proteins play critical roles in mechanical stress-induced hypertrophic responses in cardiac myocytes. Circ Res 1999; 84:458-66. [PMID: 10066681 DOI: 10.1161/01.res.84.4.458] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
-Mechanical stress induces a variety of hypertrophic responses, such as activation of protein kinases, reprogramming of gene expression, and an increase in protein synthesis. In the present study, to elucidate how mechanical stress induces such events, we examined the role of Rho family small GTP-binding proteins (G proteins) in mechanical stress-induced cardiac hypertrophy. Treatment of neonatal rat cardiomyocytes with the C3 exoenzyme, which abrogates Rho functions, suppressed stretch-induced activation of extracellular signal-regulated protein kinases (ERKs). Overexpression of the Rho GDP dissociation inhibitor (Rho-GDI), dominant-negative mutants of RhoA (DNRhoA), or DNRac1 significantly inhibited stretch-induced activation of transfected ERK2. Overexpression of constitutively active mutants of RhoA slightly activated ERK2 in cardiac myocytes. Overexpression of C-terminal Src kinase, which inhibits functions of the Src family of tyrosine kinases, or overexpression of DNRas had no effect on stretch-induced activation of transfected ERK2. The promoter activity of skeletal alpha-actin and c-fos genes was increased by stretch, and these increases were completely inhibited by either cotransfection of Rho-GDI or pretreatment with C3 exoenzyme. Mechanical stretch increased phenylalanine incorporation into cardiac myocytes by approximately 1.5-fold compared with control, and this increase was also significantly suppressed by pretreatment with C3 exoenzyme. Overexpression of Rho-GDI or DNRhoA did not affect angiotensin II-induced activation of ERK. ERKs were activated by culture media conditioned by stretch of cardiomyocytes without any treatment, but not of cardiomyocytes with pretreatment by C3 exoenzyme. These results suggest that the Rho family of small G proteins plays critical roles in mechanical stress-induced hypertrophic responses.
Collapse
Affiliation(s)
- R Aikawa
- Department of Cardiovascular Medicine, University of Tokyo Graduate School of Medicine, Japan
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Suzuki T, Shoji S, Yamamoto K, Nada S, Okada M, Yamamoto T, Honda ZI. Essential Roles of Lyn in Fibronectin-Mediated Filamentous Actin Assembly and Cell Motility in Mast Cells. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.7.3694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Although the requirement for c-Src in extracellular matrix (ECM)-mediated fibroblast motility has been well established, the roles of hemopoietic Src family protein tyrosine kinases in leukocyte migration have not been fully elucidated. To address the issue, we analyzed fibronectin (Fn)-mediated adhesion signaling in rat basophilic leukemia (RBL) 2H3 cells overexpressing 1) Csk, 2) a membrane-anchored, gain-of-function Csk (mCsk), and 3) a kinase-defective mCsk (mCsk(−)). Parent RBL2H3 cells, expressing autoactivated c-kit, readily adhered to Fn-coated surface, developed typical leukocyte adhesion machinery (podosome), and migrated toward Fn without cytokine priming, thus provided a simple experimental system to analyze Fn-mediated outside-in signaling. While overexpression of Csk or the Csk mutants did not significantly affect cell adhesion to the Fn surface or α5 integrin recruitment to the attachment sites, Csk suppressed and mCsk almost abolished Fn-mediated tyrosine phosphorylation of paxillin, filamentous actin assembly to podosomes, and cell migration, but mCsk(−) did not. Coexpression of LynA devoid of C-terminal negative regulatory tyrosine in mCsk cells successfully restored Fn-mediated podosome formation and cell migration. Coexpression of c-Src lacking the C-terminal tyrosine reconstructed podosomes, but could not restore the cell migration regardless of its expression level. Collectively, these observations provide evidence that Src family protein tyrosine kinases are required, and that Lyn could transmit sufficient signal for Fn-mediated cytoskeletal changes leading to cell locomotion in RBL2H3 cells, and they suggest that Lyn and c-Src are differentially involved in cell motility.
Collapse
Affiliation(s)
- Takeshi Suzuki
- *Department of Internal Medicine and Physical Therapy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Shunsuke Shoji
- *Department of Internal Medicine and Physical Therapy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Kazuhiko Yamamoto
- *Department of Internal Medicine and Physical Therapy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Shigeyuki Nada
- †Division of Protein Metabolism, Institute for Protein Research, Osaka University, Yamadaoka, Suita, Osaka, Japan; and
| | - Masato Okada
- †Division of Protein Metabolism, Institute for Protein Research, Osaka University, Yamadaoka, Suita, Osaka, Japan; and
| | - Tadashi Yamamoto
- ‡Department of Oncology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Zen-ichiro Honda
- *Department of Internal Medicine and Physical Therapy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| |
Collapse
|
39
|
Amrein KE, Molnos J, zur Hausen JD, Flint N, Takacs B, Burn P. Csk-mediated phosphorylation of substrates is regulated by substrate tyrosine phosphorylation. FARMACO (SOCIETA CHIMICA ITALIANA : 1989) 1998; 53:266-72. [PMID: 9658584 DOI: 10.1016/s0014-827x(98)00020-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Csk is a cellular protein tyrosine kinase (PTK) that has been shown to specifically regulate the activity of Src kinase family members by phosphorylation of a carboxy-terminal tyrosine residue. The molecular mechanisms controlling Csk regulation and its substrate specificity have not been elucidated. Here we report a novel type of overlay kinase assay that allows to probe for Csk-mediated phosphorylation of cellular substrates separated by polyacrylamide gel electrophoresis and transferred to nitrocellulose filters. Most of the cell lines analyzed with this method revealed only a few potential Csk substrates. However, an increased number of Csk substrates was detected in NIH3T3 cells expressing a constitutively activated form of the Src kinase Lck or in PC12 and NIH3T3 cells that had been treated with pervanadate. These cells all display an increased level of cellular protein tyrosine phosphorylation which led to the conclusion that Csk preferentially phosphorylates tyrosine-phosphorylated proteins. To verify this hypothesis we analyzed Csk-mediated phosphorylation of recombinant Lck, a known Csk substrate. Results demonstrated that autophosphorylation of Lck (at Tyr394) facilitates Csk-mediated phosphorylation of Lck at its regulatory site (Tyr505). Subsequent peptide binding studies revealed that Csk can bind to a peptide corresponding to the Lck-autophosphorylation site only when it is phosphorylated. These findings suggest that autophosphorylation of Lck at Tyr394 triggers an interaction with Csk and thereby facilitates subsequent phosphorylation and inactivation of Lck. The phosphorylation of other cellular Csk substrates may be regulated by a similar mechanism.
Collapse
Affiliation(s)
- K E Amrein
- Department of Metabolic Diseases, Hoffmann-La Roche Inc., Nutley, NJ 07110, USA
| | | | | | | | | | | |
Collapse
|
40
|
Rafnar T, Peebles RS, Brummet ME, Catipović B, Imani F, MacGlashan DW, Marsh DG. Stimulation of the high-affinity IgE receptor results in the tyrosine phosphorylation of a 60 kD protein which is associated with the protein-tyrosine kinase, Csk. Mol Immunol 1998; 35:249-57. [PMID: 9736341 DOI: 10.1016/s0161-5890(98)00028-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The protein tyrosine kinase Csk downregulates the activity of the Src family of kinases and has a negative effect on signal transduction through several Src kinase-associated receptors. Because the Src-family kinase Lyn plays a pivotal role in FcepsilonRI-mediated cellular activation, we examined whether Csk is involved in FcepsilonRI signaling events. Using anti-Csk antibodies and recombinant fusion proteins we detected a single tyrosine-phosphorylated protein of 60 kD (herein referred to as 'p60') that associates with the SH2 domain of Csk after stimulation of the FcepsilonRI. p60 phosphorylation reached a maximum within one minute and remained constant while the receptors were aggregated; disaggregation of the receptors resulted in rapid dephosphorylation of p60. The phosphorylation of p60 was only detected after activation by IgE and antigen and not by stimulation with PMA and/or ionomycin. Phosphorylated p60 was associated entirely with the membrane fraction of the cells. A considerable fraction of Csk was associated with the membrane in both unstimulated and stimulated cells, this fraction did not change upon activation. p60 coprecipitated with Csk from both unstimulated and FcepsilonRI stimulated cells and was phosphorylated by the immunocomplex. Total kinase activity of Csk immunoprecipitates increased upon FcepsilonRI stimulation. p60 did not react with antibodies to a number of known signaling molecules, including the recently cloned, GAP-associated protein, p62dok. Our data demonstrate that Csk associates with a membrane-anchored protein complex that is directly involved in FcepsilonRI signal transduction.
Collapse
Affiliation(s)
- T Rafnar
- Division of Clinical Immunology, Johns Hopkins Asthma and Allergy Center, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
| | | | | | | | | | | | | |
Collapse
|
41
|
Zou Y, Komuro I, Yamazaki T, Kudoh S, Aikawa R, Zhu W, Shiojima I, Hiroi Y, Tobe K, Kadowaki T, Yazaki Y. Cell type-specific angiotensin II-evoked signal transduction pathways: critical roles of Gbetagamma subunit, Src family, and Ras in cardiac fibroblasts. Circ Res 1998; 82:337-45. [PMID: 9486662 DOI: 10.1161/01.res.82.3.337] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Angiotensin II (Ang II) induces hypertrophy of cardiac myocytes and hyperplasia of cardiac fibroblasts. To determine the molecular mechanism by which Ang II displayed different effects on cardiac myocytes and fibroblasts, we examined signal transduction pathways leading to activation of extracellular signal-regulated kinases (ERKs). Ang II-induced ERK activation was abolished by pretreatment with pertussis toxin and by overexpression of the Gbetagamma subunit-binding domain of the beta-adrenergic receptor kinase 1 in cardiac fibroblasts but not in cardiac myocytes. Inhibition of protein kinase C strongly inhibited activation of ERKs by Ang II in cardiac myocytes, whereas inhibitors of tyrosine kinases but not of protein kinase C abolished Ang II-induced ERK activation in cardiac fibroblasts. Overexpression of C-terminal Src kinase (Csk), which inactivates Src family tyrosine kinases, suppressed the activation of transfected ERK in cardiac fibroblasts. Ang II rapidly induced phosphorylation of Shc and association of Shc with Grb2. Cotransfection of the dominant-negative mutant of Ras or Raf-1 kinase abolished Ang II-induced ERK activation in cardiac fibroblasts. Overexpression of Csk or the dominant-negative mutant of Ras had no effects on Ang II-induced ERK activation in cardiac myocytes. These findings suggest that Ang II-evoked signal transduction pathways differ among cell types. In cardiac fibroblasts, Ang II activates ERKs through a pathway including the Gbetagamma subunit of Gi protein, tyrosine kinases including Src family tyrosine kinases, Shc, Grb2, Ras, and Raf-1 kinase, whereas Gq and protein kinase C are important in cardiac myocytes.
Collapse
Affiliation(s)
- Y Zou
- Department of Medicine III, University of Tokyo School of Medicine, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
Src family protein tyrosine kinases are activated following engagement of many different classes of cellular receptors and participate in signaling pathways that control a diverse spectrum of receptor-induced biological activities. While several of these kinases have evolved to play distinct roles in specific receptor pathways, there is considerable redundancy in the functions of these kinases, both with respect to the receptor pathways that activate these kinases and the downstream effectors that mediate their biological activities. This chapter reviews the evidence implicating Src family kinases in specific receptor pathways and describes the mechanisms leading to their activation, the targets that interact with these kinases, and the biological events that they regulate.
Collapse
Affiliation(s)
- S M Thomas
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA.
| | | |
Collapse
|
43
|
Honda ZI, Suzuki T, Hirose N, Aihara M, Shimizu T, Nada S, Okada M, Ra C, Morita Y, Ito K. Roles of C-terminal Src kinase in the initiation and the termination of the high affinity IgE receptor-mediated signaling. J Biol Chem 1997; 272:25753-60. [PMID: 9325302 DOI: 10.1074/jbc.272.41.25753] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
As an attempt to analyze the roles of C-terminal Src kinase (Csk) in the high affinity IgE receptor (FcepsilonRI)-mediated signaling, we overexpressed Csk, a membrane-targeted form of Csk (mCsk), and a kinase-defective, membrane-targeted form of Csk (mCsk(-)) in rat basophil leukemia (RBL) 2H3 cells. Specific activity of Lyn at the basal state was decreased in Csk-expressing cells, and further decreased in mCsk-expressing cells. In mCsk(-)-expressing cells, basal specific activity of Lyn was increased, thereby indicating that mCsk(-) functioned as a dominant negative molecule. The onset of FcepsilonRI-mediated Lyn activation was delayed in Csk-expressing cells, and further delayed in mCsk-expressing cells. In mCsk(-)-expressing cells, Lyn activation was rapid and quite long lasting. These findings indicate (i) Csk negatively regulates rapid FcepsilonRI/Lyn coupling, and (ii) Csk activity is potentially required for its termination. The onsets of the series of events including tyrosyl phosphorylation of Syk, mitogen-activated protein (MAP) kinase activation, elevation of intracellular calcium concentration ([Ca2+]i), and histamine release were all stepwisely delayed in Csk-expressing cells and in mCsk-expressing cells. The durations of Syk phosphorylation and MAP kinase activation also closely correlated with those of Lyn activation, but [Ca2+]i elevation and histamine release followed different temporal patterns: the delayed responses in Csk-expressing cells and in mCsk-expressing cells led to sustained [Ca2+]i oscillation and histamine release, while the prompt responses in parent cells and mCsk(-)-expressing cells rapidly subsided. These findings provide further evidence that the initiations of the FcepsilonRI-mediated signals are upstreamly regulated by Src family protein tyrosine kinases and revealed that their terminations are regulated by Lyn-dependent (Syk and MAP kinase) and -independent ([Ca2+]i elevation and histamine release) mechanisms.
Collapse
Affiliation(s)
- Z i Honda
- Department of Internal Medicine, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Vuica M, Desiderio S, Schneck JP. Differential effects of B cell receptor and B cell receptor-FcgammaRIIB1 engagement on docking of Csk to GTPase-activating protein (GAP)-associated p62. J Exp Med 1997; 186:259-67. [PMID: 9221755 PMCID: PMC2198989 DOI: 10.1084/jem.186.2.259] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/1997] [Revised: 05/14/1997] [Indexed: 02/04/2023] Open
Abstract
The stimulatory and inhibitory pathways initiated by engagement of stimulatory receptors such as the B cell receptor for antigen (BCR) and inhibitory receptors such as Fcgamma receptors of the IIB1 type (FcgammaRIIB1) intersect in ways that are poorly understood at the molecular level. Because the tyrosine kinase Csk is a potential negative regulator of lymphocyte activation, we examined the effects of BCR and FcgammaRIIB1 engagement on the binding of Csk to phosphotyrosine-containing proteins. Stimulation of a B lymphoma cell line, A20, with intact anti-IgG antibody induced a direct, SH2-mediated association between Csk and a 62-kD phosphotyrosine-containing protein that was identified as RasGTPase-activating protein-associated p62 (GAP-A.p62). In contrast, stimulation of A20 cells with anti-IgG F(ab')2 resulted in little increase in the association of Csk with GAP-A.p62. The effect of FcgammaRIIB1 engagement on this association was abolished by blockade of FcgammaRIIB1 with the monoclonal antibody 2.4G2. Furthermore, the increased association between Csk and GAP-A.p62 seen upon stimulation with intact anti-Ig was abrogated in the FcgammaRIIB1-deficient cell line IIA1.6 and recovered when FcgammaRIIB1 expression was restored by transfection. The differential effects of BCR and BCR-FcgammaRIIB1-mediated signaling on the phosphorylation of GAP-A.p62 and its association with Csk suggest that docking of Csk to GAP-A.p62 may function in the negative regulation of antigen receptor-mediated signals in B cells.
Collapse
Affiliation(s)
- M Vuica
- Department of Pathology and Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
| | | | | |
Collapse
|
45
|
Wan Y, Bence K, Hata A, Kurosaki T, Veillette A, Huang XY. Genetic evidence for a tyrosine kinase cascade preceding the mitogen-activated protein kinase cascade in vertebrate G protein signaling. J Biol Chem 1997; 272:17209-15. [PMID: 9202044 DOI: 10.1074/jbc.272.27.17209] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The signal transduction pathway from heterotrimeric G proteins to the mitogen-activated protein kinase (MAPK) cascade is best understood in the yeast mating pheromone response, in which a serine/threonine protein kinase (STE20) serves as the critical linking component. Little is known in metazoans on how G proteins and the MAPK cascade are coupled. Here we provide genetic and biochemical evidence that a tyrosine kinase cascade bridges G proteins and the MAPK pathway in vertebrate cells. Targeted deletion of tyrosine kinase Csk in avian B lymphoma cells blocks the stimulation of MAPK by Gq-, but not Gi-, coupled receptors. In cells deficient in Bruton's tyrosine kinase (Btk), Gi-coupled receptors failed to activate MAPK, while Gq-coupled receptor-mediated stimulation is unaffected. Taken together with our previous data on tyrosine kinases Lyn and Syk, the Gq-coupled pathway requires tyrosine kinases Csk, Lyn, and Syk, while the Gi-coupled pathway requires tyrosine kinases Btk and Syk to feed into the MAPK cascade in these cells. The central role of Syk is further strengthened by data showing that Syk can bind to purified Lyn, Csk, or Btk.
Collapse
Affiliation(s)
- Y Wan
- Department of Physiology, Cornell University Medical College, New York, New York 10021, USA
| | | | | | | | | | | |
Collapse
|
46
|
Abstract
Recent gene-targeting experiments have highlighted the importance of the intracellular protein tyrosine kinases Lyn, Syk, and Btk in BCR signal transduction and B cell development. In addition, the interactions of these kinases and their regulatory mechanisms have been reported. Activation loop phosphorylation of these kinases is critical for their participation in signal propagation. Several substrates have been identified for these kinases and this has led to elucidation of the mechanisms by which these kinases mediate the downstream signaling events that lead to cellular responses of B cells.
Collapse
Affiliation(s)
- T Kurosaki
- Department of Molecular Genetics, Institute for Hepatic Research Kansai, Medical University, 10-15 Fumizono-cho, Moriguchi, Osaka, 570, Japan.
| |
Collapse
|
47
|
Iwabuchi K, Hatakeyama S, Takahashi A, Ato M, Okada M, Kajino Y, Kajino K, Ogasawara K, Takami K, Nakagawa H, Onoé K. Csk overexpression reduces several monokines and nitric oxide productions but enhances prostaglandin E2 production in response to lipopolysaccharide in the macrophage cell line J774A.1. Eur J Immunol 1997; 27:742-9. [PMID: 9079817 DOI: 10.1002/eji.1830270324] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The catalytic activity of src-family protein tyrosine kinases (src-PTK) is suppressed when a C-terminal tyrosine is phosphorylated by an intracellular PTK, C-terminal Src kinase (Csk). In the present report, to study the regulatory functions of the Csk in cells of monocyte/macrophage lineage, we transfected a eukaryotic expression vector containing rat csk cDNA in a macrophage cell line, J774A.1, and examined alterations of the response to lipopolysaccharide (LPS) in the transfectants which overexpressed Csk. Csk overexpression resulted primarily in a down-regulation of Fgr activity, an src-PTK expressed in J774A.1, and hyperphosphorylation of several cellular proteins of 35, 57, 66, 97 and 120-130 kDa. Furthermore, in these Csk transfectants, production of interleukin (IL)-1alpha, IL-6, tumor necrosis factor-alpha, and nitric oxide (NO) following LPS stimulation were reduced compared with those in parental J774A.1 or J774A.1 transfected with the vector alone. The extent of reduction paralleled the amounts of Csk proteins expressed in the Csk-transfected J774A.1. The reduced NO production in these cells was associated with low levels of mRNA of inducible NO synthetase. On the other hand, an enhancement of prostaglandin E2 production was observed in the Csk-transfected J774A.1 cells upon stimulation with LPS, which appeared to result from the high level of prostaglandin-H synthetase in the transfectants. The present findings indicate that overexpression of Csk has differential effects on the regulation of production of chemical mediators and monokines, probably via modulation of signal transduction downstream of LPS-mediated signals.
Collapse
Affiliation(s)
- K Iwabuchi
- Institute of Immunological Science, Hokkaido University, Kita-ku, Sapporo, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
Current models of signal transduction from the antigen receptors on B and T cells still resemble equations with several unknown elements. Data from recent knockout experiments in cell lines and mice contradict the assumption that Src-family kinase and tyrosine kinases of the Syk/Zap-70 family are the transducer elements that set signaling from these receptors in motion. Using a functional definition of signaling elements, we discuss the current knowledge of signaling events from the BCR and suggest the existence of an as-yet-unknown BCR transducer complex.
Collapse
Affiliation(s)
- M Reth
- Department of Molecular Immunology, Biology III, University Freiburg, Germany.
| | | |
Collapse
|
49
|
Abstract
Intracellular signal transduction following the extracellular ligation of a wide variety of different types of surface molecules on leukocytes involves the activation of protein tyrosine kinases. The dependence of successful intracellular signaling on the functions of the nontransmembrane class of protein tyrosine kinases coupled with the cell type-specific expression patterns for several of these enzymes makes them appealing targets for therapeutic intervention. Development of drugs that can interfere with the catalytic functions of the nontransmembrane protein tyrosine kinases or that can disrupt critical interactions with regulatory molecules and/or substrates should find clinical applications in the treatment of allergic diseases, autoimmunity, transplantation rejection, and cancer.
Collapse
Affiliation(s)
- J B Bolen
- DNAX Research Institute, Palo Alto, California 94304, USA.
| | | |
Collapse
|
50
|
Zou Y, Komuro I, Yamazaki T, Aikawa R, Kudoh S, Shiojima I, Hiroi Y, Mizuno T, Yazaki Y. Protein kinase C, but not tyrosine kinases or Ras, plays a critical role in angiotensin II-induced activation of Raf-1 kinase and extracellular signal-regulated protein kinases in cardiac myocytes. J Biol Chem 1996; 271:33592-7. [PMID: 8969227 DOI: 10.1074/jbc.271.52.33592] [Citation(s) in RCA: 168] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Angiotensin II (AngII) induces cardiac hypertrophy through activating a variety of protein kinases. In this study, to understand how cardiac hypertrophy develops, we examined AngII-evoked signal transduction pathways leading to the activation of extracellular signal-regulated protein kinases (ERKs), which are reportedly critical for the development of cardiac hypertrophy, in cultured cardiac myocytes isolated from neonatal rats. Inhibition of protein kinase C (PKC) with calphostin C or down-regulation of PKC by pretreatment with a phorbol ester for 24 h abolished AngII-induced activation of Raf-1 and ERKs, and addition of a phorbol ester conversely induced a marked increase in the activities of Raf-1 and ERKs. Pretreatment with two chemically and mechanistically dissimilar tyrosine kinase inhibitors, genistein and tyrphostin, did not attenuate AngII-induced activation of ERKs. In contrast, genistein strongly blocked insulin-induced ERK activation in cardiac myocytes. Although pretreatment with manumycin, a Ras farnesyltransferase inhibitor, or overexpression of a dominant-negative mutant of Ras inhibited insulin-induced ERK activation, neither affected AngII-induced activation of ERKs. Overexpression of a dominant-negative mutant of Raf-1 completely suppressed ERK2 activation by AngII, endothelin-1, and insulin. These results suggest that PKC and Raf-1, but not tyrosine kinases or Ras, are critical for AngII-induced activation of ERKs in cardiac myocytes.
Collapse
Affiliation(s)
- Y Zou
- Department of Medicine III, University of Tokyo School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|