TEC-/- BTK-/- double mutant T cells exhibit severely impaired T cell activitity.
1: J Exp Med. 2000 Dec 4;192(11):1611-24.
Severe B cell deficiency in mice lacking the tec kinase family members Tec and
Btk.
Ellmeier W, Jung S, Sunshine MJ, Hatam F, Xu Y, Baltimore D, Mano H, Littman DR.
Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine.
[email protected]
The cytoplasmic protein tyrosine kinase Tec has been proposed to have important
functions in hematopoiesis and lymphocyte signal transduction. Here we show that
Tec-deficient mice developed normally and had no major phenotypic alterations of
the immune system. To reveal potential compensatory roles of other Tec kinases
such as Bruton's tyrosine kinase (Btk), Tec/Btk double-deficient mice were
generated. These mice exhibited a block at the B220(+)CD43(+) stage of B cell
development and displayed a severe reduction of peripheral B cell numbers,
particularly immunoglobulin (Ig)M(lo)IgD(hi) B cells. Although Tec/Btk(null)
mice were able to form germinal centers, the response to T cell-dependent
antigens was impaired. Thus, Tec and Btk together have an important role both
during B cell development and in the generation and/or function of the
peripheral B cell pool. The ability of Tec to compensate for Btk may also
explain phenotypic differences in X-linked immunodeficiency (xid) mice compared
with human X-linked agammaglobulinemia (XLA) patients.
Publication Types:
Research Support, Non-U.S. Gov't
PMID: 11104803 [PubMed - indexed for MEDLINE]
RLK-/-ITK-/- double mutant celles exhibit severely imparired Th2 responses.
1: Nat Immunol. 2001 Dec;2(12):1183-8.
Mutation of Tec family kinases alters T helper cell differentiation.
Schaeffer EM, Yap GS, Lewis CM, Czar MJ, McVicar DW, Cheever AW, Sher A,
Schwartzberg PL.
National Human Genome Research Institute, National Institutes of Health,
Bethesda, MD 20892, USA.
The Tec kinases Rlk and Itk are critical for full T cell receptor (TCR)-induced
activation of phospholipase C-gamma and mitogen-activated protein kinase. We
show here that the mutation of Rlk and Itk impaired activation of the
transcription factors NFAT and AP-1 and production of both T helper type 1 (TH1)
and TH2 cytokines. Consistent with these biochemical defects, Itk-/- mice did
not generate effective TH2 responses when challenged with Schistosoma mansoni
eggs. Paradoxically, the more severely impaired Rlk-/-Itk-/- mice were able to
mount a TH2 response and produced TH2 cytokines in response to this challenge.
In addition, Rlk-/-Itk-/- cells showed impaired TCR-induced repression of the
TH2-inducing transcription factor GATA-3, suggesting a potential mechanism for
TH2 development in these hyporesponsive cells. Thus, mutations that affect Tec
kinases lead to complex alterations in CD4+ TH cell differentiation.
Publication Types:
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
PMID: 11702066 [PubMed - indexed for MEDLINE]
Grb2(+/-) mice disrupt T cell signaling networks and development.
1: Nat Immunol. 2001 Jan;2(1):29-36.
Disruption of T cell signaling networks and development by Grb2 haploid
insufficiency.
Gong Q, Cheng AM, Akk AM, Alberola-Ila J, Gong G, Pawson T, Chan AC.
Howard Hughes Medical Institute, Washington University School of Medicine, St.
Louis, MO 63110, USA.
The developmental processes of positive and negative selection in the thymus
shape the T cell antigen receptor (TCR) repertoire and require the integration
of multiple signaling networks. These networks involve the efficient assembly of
macromolecular complexes and are mediated by multimodular adaptor proteins that
permit the functional integration of distinct signaling molecules. We show here
that decreased expression of the adaptor protein Grb2 in Grb2+/- mice weakens
TCR-induced c-Jun N-terminal kinase (JNK) and p38, but not extracellular
signal-regulated kinase (ERK), activation. In turn, this selective effect
decreases the ability of thymocytes to undergo negative, but not positive,
selection. We also show that there are differences in the signaling thresholds
of the three mitogen-activated protein kinase (MAPK) families. These differences
may provide a mechanism by which quantitative differences in signal strength can
alter the balance of downstream signaling pathways to induce the qualitatively
distinct biological outcomes of proliferation, differentiation or apoptosis.
PMID: 11135575 [PubMed - indexed for MEDLINE]
Dendric cells and macrophages of MEK3 deficient mice have impaired IL12 production.
1: EMBO J. 1999 Apr 1;18(7):1845-57.
Defective IL-12 production in mitogen-activated protein (MAP) kinase kinase 3
(Mkk3)-deficient mice.
Lu HT, Yang DD, Wysk M, Gatti E, Mellman I, Davis RJ, Flavell RA.
Howard Hughes Medical Institute and Section of Immunobiology, Yale University
School of Medicine, New Haven, CT 06520, USA.
The p38 mitogen-activated protein kinase (MAPK) pathway, like the c-Jun
N-terminal kinase (JNK) MAPK pathway, is activated in response to cellular
stress and inflammation and is involved in many fundamental biological
processes. To study the role of the p38 MAPK pathway in vivo, we have used
homologous recombination in mice to inactivate the Mkk3 gene, one of the two
specific MAPK kinases (MAPKKs) that activate p38 MAPK. Mkk3(-/-) mice were
viable and fertile; however, they were defective in interleukin-12 (IL-12)
production by macrophages and dendritic cells. Interferon-gamma production
following immunization with protein antigens and in vitro differentiation of
naive T cells is greatly reduced, suggesting an impaired type I cytokine immune
response. The effect of the p38 MAPK pathway on IL-12 expression is at least
partly transcriptional, since inhibition of this pathway blocks IL-12 p40
promoter activity in macrophage cell lines and IL-12 p40 mRNA is reduced in
MKK3-deficient mice. We conclude that the p38 MAP kinase, activated through
MKK3, is required for the production of inflammatory cytokines by both
antigen-presenting cells and CD4(+) T cells.
PMID: 10202148 [PubMed - indexed for MEDLINE]
Bam32(-/-) B cell develop normally but have impaired T-independent antibody responses in vivo.
1: Immunity. 2003 Oct;19(4):621-32.
Bam32 links the B cell receptor to ERK and JNK and mediates B cell proliferation
but not survival.
Han A, Saijo K, Mecklenbrauker I, Tarakhovsky A, Nussenzweig MC.
Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
10021, USA.
Bam32 is an adaptor protein recruited to the plasma membrane upon B cell
receptor (BCR) crosslinking in a phosphoinositol 3-kinase (PI3K)-dependent
manner; however, its physiologic function is unclear. To determine its
physiologic function, we produced Bam32-deficient mice. Bam32(-/-) B cells
develop normally but have impaired T-independent antibody responses in vivo and
diminished responses to BCR crosslinking in vitro. Biochemical analysis revealed
that Bam32 acts in a novel pathway leading from the BCR to MAPK/ERK Kinases
(MEK1/2), MAPK/ERK Kinase Kinase-1 (MEKK1), extracellular signal-regulated
kinase (ERK), and c-jun NH2-terminal kinase (JNK), but not p38 mitogen-activated
protein kinase (p38). This pathway appears to be initiated by hematopoietic
progenitor kinase-1 (HPK1), which interacts directly with Bam32, and differs
from all previously characterized BCR signaling pathways in that it is required
for normal BCR-mediated proliferation but not for B cell survival.
PMID: 14563325 [PubMed - indexed for MEDLINE]
T-cell and B-cell of RAP1A deficient mice impair integrin-mediated cell adhesion.
1: Mol Cell Biol. 2006 Jan;26(2):643-53.
Rap1A-deficient T and B cells show impaired integrin-mediated cell adhesion.
Duchniewicz M, Zemojtel T, Kolanczyk M, Grossmann S, Scheele JS, Zwartkruis FJ.
Department of Computational Molecular Biology, Max Planck Institute for
Molecular Genetics, Ihnestrasse 73, D-14195 Berlin, Germany.
Studies in tissue culture cells have demonstrated a role for the Ras-like GTPase
Rap1 in the regulation of integrin-mediated cell-matrix and cadherin-mediated
cell-cell contacts. To analyze the function of Rap1 in vivo, we have disrupted
the Rap1A gene by homologous recombination. Mice homozygous for the deletion
allele are viable and fertile. However, primary hematopoietic cells isolated
from spleen or thymus have a diminished adhesive capacity on ICAM and
fibronectin substrates. In addition, polarization of T cells from Rap1-/- cells
after CD3 stimulation was impaired compared to that of wild-type cells. Despite
this, these defects did not result in hematopoietic or cell homing
abnormalities. Although it is possible that the relatively mild phenotype is a
consequence of functional complementation by the Rap1B gene, our genetic studies
confirm a role for Rap1A in the regulation of integrins.
PMID: 16382154 [PubMed - indexed for MEDLINE]
T-cell of WASP deficient mice impair the proliferaction and antigen receptor cap formation in response to anti-CD3zeta stimulation.
1: Immunity. 1998 Jul;9(1):81-91.
Wiskott-Aldrich syndrome protein-deficient mice reveal a role for WASP in T but
not B cell activation.
Snapper SB, Rosen FS, Mizoguchi E, Cohen P, Khan W, Liu CH, Hagemann TL, Kwan
SP, Ferrini R, Davidson L, Bhan AK, Alt FW.
Howard Hughes Medical Institute, Children's Hospital, Boston, Massachusetts
02115, USA.
The Wiskott-Aldrich syndrome (WAS) is a human X-linked immunodeficiency
resulting from mutations in a gene (WASP) encoding a cytoplasmic protein
implicated in regulating the actin cytoskeleton. To elucidate WASP function, we
disrupted the WASP gene in mice by gene-targeted mutation. WASP-deficient mice
showed apparently normal lymphocyte development, normal serum immunoglobulin
levels, and the capacity to respond to both T-dependent and T-independent type
II antigens. However, these mice did have decreased peripheral blood lymphocyte
and platelet numbers and developed chronic colitis. Moreover, purified
WASP-deficient T cells showed markedly impaired proliferation and antigen
receptor cap formation in response to anti-CD3epsilon stimulation. Yet, purified
WASP-deficient B cells showed normal responses to anti-Ig stimulation. We
discuss the implications of our findings regarding WASP function in receptor
signaling and cytoskeletal reorganization in T and B cells and compare the
effects of WASP deficiency in mice and humans.
PMID: 9697838 [PubMed - indexed for MEDLINE]
T-cell of SHB defective mice impair the phosphorylation of LAT and consequently the activation of MAP kinase pathways.
9 Sep 24;274(39):28050-7.
Requirement of the Src homology 2 domain protein Shb for T cell
receptor-dependent activation of the interleukin-2 gene nuclear factor for
activation of T cells element in Jurkat T cells.
Lindholm CK, Gylfe E, Zhang W, Samelson LE, Welsh M.
Department of Medical Cell Biology, Box 571, Biomedicum, Uppsala University,
S-75123 Uppsala, Sweden.
Stimulation of the T cell antigen receptor (TCR) induces tyrosine
phosphorylation of numerous intracellular proteins. We have recently
investigated the role of the adaptor protein Shb in the early events of T cell
signaling and observed that Shb associates with Grb2, linker for activation of T
cells (LAT) and the TCR zeta-chain in Jurkat cells. We now report that Shb also
associates with phospholipase C-gamma1 (PLC-gamma1) in these cells.
Overexpression of Src homology 2 domain defective Shb caused diminished
phosphorylation of LAT and consequently the activation of mitogen-activated
protein kinases was decreased upon TCR stimulation. In addition, the Shb mutant
also blocked phosphorylation of PLC-gamma1 and the increase in cytoplasmic
Ca(2+) following TCR stimulation. Nuclear factor for activation of T cells is a
major target for Ras and calcium signaling pathways in T cells following TCR
stimulation, and the overexpression of the mutant Shb prevented TCR-dependent
activation of the nuclear factor for activation of T cells. Consequently,
endogenous interleukin-2 production was decreased under these conditions. The
results indicate a role for Shb as a link between the TCR and downstream
signaling events involving LAT and PLC-gamma1 and resulting in the activation of
transcription of the interleukin-2 gene.
PMID: 10488157 [PubMed - indexed for MEDLINE]
B-cell of 3BP2 (-/-) deficient mice have defective in proliferation, cell cycle progression, PLC-gamma2 phosphorylation, calcium mobilization, NF-ATp dephosphorylation, and Erk and Jnk activation in response to BCR ligation.
1: Mol Cell Biol. 2006 Jul;26(14):5214-25.
3BP2 deficiency impairs the response of B cells, but not T cells, to antigen
receptor ligation.
de la Fuente MA, Kumar L, Lu B, Geha RS.
Division of Immunology, Children's Hospital, 300 Longwood Ave., Boston, MA
02115, USA.
The adapter protein 3BP2 is expressed in lymphocytes; binds to Syk/ZAP-70, Vav,
and phospholipase C-gamma (PLC-gamma); and is thought to be important for
interleukin-2 gene transcription in T cells. To define the role of 3BP2 in
lymphocyte development and function, we generated 3BP2-deficient mice. T-cell
development, proliferation, cytokine secretion, and signaling in response to
T-cell receptor (TCR) ligation were all normal in 3BP2(-/-) mice. 3BP2(-/-) mice
had increased accumulation of pre-B cells in the bone marrow and a block in the
progression of transitional B cells in the spleen from the T1 to the T2 stage,
but normal numbers of mature B cells. B-cell proliferation, cell cycle
progression, PLC-gamma2 phosphorylation, calcium mobilization, NF-ATp
dephosphorylation, and Erk and Jnk activation in response to B-cell receptor
(BCR) ligation were all impaired. These results suggest that 3BP2 is important
for BCR, but not for TCR signaling.
PMID: 16809760 [PubMed - indexed for MEDLINE]
B-cell of Vav2(-/-) deficient mice are defective in the ability to switch immunoglobulin class.
1: Nat Immunol. 2001 Jun;2(6):542-7.
Comment in:
Nat Immunol. 2001 Jun;2(6):482-4.
Signal transduction through Vav-2 participates in humoral immune responses and B
cell maturation.
Doody GM, Bell SE, Vigorito E, Clayton E, McAdam S, Tooze R, Fernandez C, Lee
IJ, Turner M.
Laboratory of Lymphocyte Signaling and Development, Molecular Immunology
Programme, The Babraham Institute, Babraham, Cambridge CB2 4AT, UK.
B and T lymphocytes develop normally in mice lacking the guanine nucleotide
exchange factor Vav-2. However, the immune responses to type II
thymus-independent antigen as well as the primary response to thymus-dependent
(TD) antigen are defective. Vav-2-deficient mice are also defective in their
ability to switch immunoglobulin class, form germinal centers and generate
secondary immune responses to TD antigens. Mice lacking both Vav-1 and Vav-2
contain reduced numbers of B lymphocytes and display a maturational block in the
development of mature B cells. B cells from Vav-1(-/-)Vav-2(-/-) mice respond
poorly to antigen receptor triggering, both in terms of proliferation and
calcium release. These studies show the importance of Vav-2 in humoral immune
responses and B cell maturation.
PMID: 11376342 [PubMed - indexed for MEDLINE]
T-cell of Vav1(-/-) deficient mice exhibit impaired antigen receptor signaling.
1: Nature. 1995 Mar 30;374(6521):474-7.
Defective T-cell receptor signalling and positive selection of Vav-deficient
CD4+ CD8+ thymocytes.
Fischer KD, Zmuldzinas A, Gardner S, Barbacid M, Bernstein A, Guidos C.
Program in Molecular Biology and Cancer, Samuel Lunenfeld Research Institute,
Mount Sinai Hospital, Toronto, Ontario, Canada.
During lymphocyte development, cellular proliferation and positive and negative
selection events ensure the production of T and B lymphocytes bearing highly
diverse, but self-tolerant, repertoires of antigen receptors. These processes
are initiated when engagement of growth-factor receptors, or the T and B
lymphocyte antigen receptors, induces tyrosine phosphorylation of specific SH2-
and SH3-domain-containing cytoplasmic proteins, including Vav. Here we show that
vav-/- embryonic stem cells generate only limited numbers of immature and mature
T and B lymphocytes in the RAG-2 blastocyst complementation assay. Furthermore,
Vav-deficient T lymphocytes showed severely impaired antigen receptor
signalling. Finally, we demonstrate that Vav-dependent signalling pathways
regulate maturation, but not CD4/CD8 lineage commitment, during
T-cell-receptor-mediated positive selection of immature CD4+ CD8+ precursors
into mature CD4+ CD8- or CD4- CD8+ T cells.
PMID: 7700360 [PubMed - indexed for MEDLINE]
Vav1(-/-)Vav2(-/-) mice exhibit greatly reduced the mature B-cells. Vav-1-/-Vav-2-/- B cells were unresponsive to BCR-driven proliferation in vitro and to thymus-indepen-dent antigen in vivo.
1: Nat Immunol. 2001 Jun;2(6):548-55.
Comment in:
Nat Immunol. 2001 Jun;2(6):482-4.
Compensation between Vav-1 and Vav-2 in B cell development and antigen receptor
signaling.
Tedford K, Nitschke L, Girkontaite I, Charlesworth A, Chan G, Sakk V, Barbacid
M, Fischer KD.
Abteilung Physiologische Chemie, Universitat Ulm, Albert-Einstein-Allee 11,
D-89069 Ulm, Germany.
Vav-1 and Vav-2 are closely related Dbl-homology GTP exchange factors (GEFs) for
Rho GTPases. Mutation of Vav-1 disrupts T cell development and T cell antigen
receptor-induced activation, but has comparatively little effect on B cells. We
found that combined deletion of both Vav-1 and Vav-2 in mice resulted in a
marked reduction in mature B lymphocyte numbers. Vav-1(-/-)Vav-2(-/-) B cells
were unresponsive to B cell antigen receptor (BCR)-driven proliferation in vitro
and to thymus-independent antigen in vivo. BCR-stimulated intracellular calcium
mobilization was greatly impaired in Vav-1(-/-)Vav-2(-/-) B cells. These
findings establish a role for Vav-2 in BCR calcium signaling and reveal that the
Vav family of GEFs is critical to B cell development and function.
PMID: 11376343 [PubMed - indexed for MEDLINE]
Fyn-deficient mice exhibit a remarkably specific lymphoid defect: thymocytes are refractile to stimulation through the TCR with mitogen or antigen.
1: Cell. 1992 Sep 4;70(5):751-63.
Defective T cell receptor signaling in mice lacking the thymic isoform of
p59fyn.
Appleby MW, Gross JA, Cooke MP, Levin SD, Qian X, Perlmutter RM.
Howard Hughes Medical Institute, Department of Immunology, University of
Washington, Seattle 98195.
Considerable evidence supports the hypothesis that the nonreceptor protein
tyrosine kinase p59fyn participates in signal transduction from the T cell
receptor (TCR). To examine this hypothesis in detail, we have produced mice that
lack the thymic isoform of p59fyn but retain expression of the brain isoform of
the protein. fynTnull mice exhibit a remarkably specific lymphoid defect:
thymocytes are refractile to stimulation through the TCR with mitogen or
antigen, while peripheral T cells, following what appears to be a normal
maturation sequence, reacquire significant signaling capabilities. These data
confirm that p59fynT plays a pivotal role in TCR signal transduction and
demonstrate that additional developmentally regulated signaling components also
contribute to TCR-induced lymphocyte activation.
PMID: 1516132 [PubMed - indexed for MEDLINE]
Lck-deficient mice show a pronounced thymic atrophy, with a dramatic reduction in the double-positive (CD4+CD8+) thymocyte population.
1: Nature. 1992 May 14;357(6374):161-4.
Comment in:
Nature. 1993 Jan 21;361(6409):213.
Profound block in thymocyte development in mice lacking p56lck.
Molina TJ, Kishihara K, Siderovski DP, van Ewijk W, Narendran A, Timms E,
Wakeham A, Paige CJ, Hartmann KU, Veillette A, et al.
Ontario Cancer Institute, University of Toronto, Canada.
The protein Lck (p56lck) has a relative molecular mass of 56,000 and belongs to
the Src family of tyrosine kinases. It is expressed exclusively in lymphoid
cells, predominantly in thymocytes and peripheral T cells. Lck associates
specifically with the cytoplasmic domains of both CD4 and CD8 T-cell surface
glycoproteins and interacts with the beta-chain of the interleukin-2 receptor,
which implicates Lck activity in signal transduction during thymocyte ontogeny
and activation of mature T cells. Here we generate an lck null mutation by
homologous recombination in embryonic stem cells to evaluate the role of p56lck
in T-cell development and activation. Lck-deficient mice show a pronounced
thymic atrophy, with a dramatic reduction in the double-positive (CD4+CD8+)
thymocyte population. Mature, single-positive thymocytes are not detectable in
these mice and there are only very few peripheral T cells. These results
illustrate the crucial role of this T-cell-specific tyrosine kinase in the
thymocyte development.
PMID: 1579166 [PubMed - indexed for MEDLINE]
T cell from mice deficient in LCK is required for normal signal transduction through the TCR.
1: Cell. 1992 Aug 21;70(4):585-93.
Genetic evidence for the involvement of the lck tyrosine kinase in signal
transduction through the T cell antigen receptor.
Straus DB, Weiss A.
Howard Hughes Medical Institute, Department of Medicine, University of
California, San Francisco 94143.
Signaling through the T cell antigen receptor (TCR) results both in rapid
increases in tyrosine phosphorylation on a number of proteins and in the
activation of the phosphatidylinositol pathway. It is not clear how stimulation
of the TCR leads to these signaling events. Mutants of the Jurkat T cell line
have been previously isolated that fail to show increases in calcium following
receptor stimulation. Analysis of one of these mutants, JCaM1, which is
defective in the induction of tyrosine phosphorylation, revealed a defect in the
expression of functional lck tyrosine kinase. The lack of lck activity was
caused in part by a splicing defect. Expression of the lck cDNA in JCaM1
restores the ability of the cell to respond to TCR stimulation. These results
indicate that lck is required for normal signal transduction through the TCR.
PMID: 1505025 [PubMed - indexed for MEDLINE]
T cells from mice deficient in SLAP-130/Fyb show markedly impaired proliferation.
1: Science. 2001 Sep 21;293(5538):2263-5.
Coupling of the TCR to integrin activation by Slap-130/Fyb.
Peterson EJ, Woods ML, Dmowski SA, Derimanov G, Jordan MS, Wu JN, Myung PS, Liu
QH, Pribila JT, Freedman BD, Shimizu Y, Koretzky GA.
The Abramson Family Cancer Research Institute, Department of Medicine, School of
Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
SLAP-130/Fyb (SLP-76-associated phosphoprotein or Fyn-binding protein; also
known as Fyb/Slap) is a hematopoietic-specific adapter, which associates with
and modulates function of SH2-containing leukocyte phosphoprotein of 76
kilodaltons (SLP-76). T cells from mice lacking SLAP-130/Fyb show markedly
impaired proliferation following CD3 engagement. In addition, the T cell
receptor (TCR) in SLAP-130/Fyb mutant cells fails to enhance integrin-dependent
adhesion. Although TCR-induced actin polymerization is normal, TCR-stimulated
clustering of the integrin LFA-1 is defective in SLAP-130/Fyb-deficient cells.
These data indicate that SLAP-130/Fyb is important for coupling TCR-mediated
actin cytoskeletal rearrangement with activation of integrin function, and for T
cells to respond fully to activating signals.
PMID: 11567141 [PubMed - indexed for MEDLINE]
B cell of chicken deficient ITK reduce IP3 generation and phospholipase C gamma 2 tyrosine phosphorylation.
1: J Exp Med. 1996 Jul 1;184(1):31-40.
A role for Bruton's tyrosine kinase in B cell antigen receptor-mediated
activation of phospholipase C-gamma 2.
Takata M, Kurosaki T.
Department of Oncology and Immunology, Wyeth-Ayerst Research, Pearl River, New
York 10965, USA.
Defects in the gene encoding Bruton's tyrosine kinase (Btk) result in a disease
called X-linked agammaglobulinemia, in which there is a profound decrease of
mature B cells due to a block in B cell development. Recent studies have shown
that Btk is tyrosine phosphorylated and activated upon B cell antigen receptor
(BCR) stimulation. To elucidate the functions of this kinase, we examined BCR
signaling of DT40 B cells deficient in Btk. Tyrosine phosphorylation of
phospholipase C (PLC)-gamma 2 upon receptor stimulation was significantly
reduced in the mutant cells, leading to the loss of both BCR-coupled
phosphatidylinositol hydrolysis and calcium mobilization. Pleckstrin homology
and Src-homology 2 domains of Btk were required for PLC-gamma 2 activation.
Since Syk is also required for the BCR-induced PLC-gamma 2 activation, our
findings indicate that PLC-gamma 2 activation is regulated by Btk and Syk
through their concerted actions.
PMID: 8691147 [PubMed - indexed for MEDLINE]
T cell of mice deficient ITK reduce IP3 generation and phospholipase C gamma 1 tyrosine phosphorylation.
1: J Exp Med. 1998 May 18;187(10):1721-7.
T cell receptor-initiated calcium release is uncoupled from capacitative calcium
entry in Itk-deficient T cells.
Liu KQ, Bunnell SC, Gurniak CB, Berg LJ.
Program of Immunology, Division of Medical Sciences, Harvard University, Boston,
Massachusetts 02115, USA.
Itk, a Tec family tyrosine kinase, plays an important but as yet undefined role
in T cell receptor (TCR) signaling. Here we show that T cells from Itk-deficient
mice have a TCR-proximal signaling defect, resulting in defective interleukin 2
secretion. Upon TCR stimulation, Itk-/- T cells release normal amounts of
calcium from intracellular stores, but fail to open plasma membrane calcium
channels. Since thapsigargin-induced store depletion triggers normal calcium
entry in Itk-/- T cells, an impaired biochemical link between store depletion
and channel opening is unlikely to be responsible for this defect. Biochemical
studies indicate that TCR-induced inositol 1,4,5 tris-phosphate (IP3) generation
and phospholipase C gamma1 tyrosine phosphorylation are substantially reduced in
Itk-/- T cells. In contrast, TCR-zeta and ZAP-70 are phosphorylated normally,
suggesting that Itk functions downstream of, or in parallel to, ZAP-70 to
facilitate TCR-induced IP3 production. These findings support a model in which
quantitative differences in cytosolic IP3 trigger distinct responses, and in
which only high concentrations of IP3 trigger the influx of extracellular
calcium.
PMID: 9584150 [PubMed - indexed for MEDLINE]
T cell of mice deficient ITK have failure of Th2 development.
1: Immunity. 1999 Oct;11(4):399-409.
Impaired NFATc translocation and failure of Th2 development in Itk-deficient
CD4+ T cells.
Fowell DJ, Shinkai K, Liao XC, Beebe AM, Coffman RL, Littman DR, Locksley RM.
Department of Medicine, University of California San Francisco 94143, USA.
Naive Itk-deficient CD4+ T cells were unable to establish stable IL-4
production, even when primed in Th2-inducing conditions. In contrast, IFNgamma
production was little affected. Failure to express IL-4 occurred even among
cells that had gone through multiple cell divisions and was associated with a
delay in the kinetics and magnitude of NFATc nuclear localization. IL-4
production was restored genetically by retroviral reconstitution of Itk or
biochemically by augmenting the calcium flux with ionomycin. In vivo,
Itk-deficient mice were unable to establish functional Th2 cells. Development of
protective Th1 cells was unimpeded. These data define a nonredundant role for
Itk in modulating signals from the TCR/CD28 pathways that are specific for the
establishment of stable IL-4 but not IFNgamma expression.
PMID: 10549622 [PubMed - indexed for MEDLINE]
Mice deficient in ITK have reduced proliferative responses to MHC stimulation and to anti-TCR cross-linking
1: Immunity. 1995 Dec;3(6):757-69.
Altered T cell receptor signaling and disrupted T cell development in mice
lacking Itk.
Liao XC, Littman DR.
Department of Microbiology and Immunology, University of California, San
Francisco 94143-0414, USA.
Itk is a T cell protein tyrosine kinase (PTK) that, along with Btk and Tec,
belongs to a family of cytoplasmic PTKs with N-terminal pleckstrin homology
domains. Btk plays a critical role in B lymphocyte development. To determine
whether Itk has an analogous role in T lymphocytes, we used gene targeting to
prepare mice lacking expression of Itk. Such animals had decreased numbers of
mature thymocytes, an effect most clearly observed in mice expressing T cell
receptor (TCR) transgenes. Mature T cells from Itk-deficient mice had reduced
proliferative responses to allogeneic MHC stimulation and to anti-TCR
cross-linking, but responded normally to stimulation with phorbol ester plus
ionomycin or with IL-2. These results provide genetic evidence that Itk is
involved in T cell development and also suggest that Itk has an important role
in proximal events in TCR-mediated signaling pathways.
PMID: 8777721 [PubMed - indexed for MEDLINE]
Mutations in Btk cause X-linked immunodeficiency.
1: Semin Immunol. 1998 Aug;10(4):309-16.
Btk function in B cell development and response.
Satterthwaite AB, Li Z, Witte ON.
Department of Microbiology and Molecular Genetics, University of California, Los
Angeles 90095-1662, USA.
Mutations in Bruton's tyrosine kinase (Btk) result in the B cell
immunodeficiencies XLA in humans and Xid in mice. Both the maintenance of
peripheral B cell numbers and their response to B cell antigen receptor (BCR)
crosslinking depend on Btk. Btk integrates signals from multiple cell surface
receptors, including BCR and G-protein coupled receptors. These Btk dependent
signals control B cell proliferation and survival by mediating Ca2+ flux,
activating JNK and p38 and inducing cell cycle regulatory genes.
Publication Types:Review
PMID: 9695187 [PubMed - indexed for MEDLINE]
Gads(GRAP2) has a role in thymocyte proliferaction for maturation of T-cells.
1: Science. 2001 Mar 9;291(5510):1987-91.
Requirement for the SLP-76 adaptor GADS in T cell development.
Yoder J, Pham C, Iizuka YM, Kanagawa O, Liu SK, McGlade J, Cheng AM.
Medical Scientist Training Program, Washington University School of Medicine,
St. Louis, MO 63110, USA.
GADS is an adaptor protein implicated in CD3 signaling because of its ability to
link SLP-76 to LAT. A GADS-deficient mouse was generated by gene targeting, and
the function of GADS in T cell development and activation was examined. GADS-
CD4-CD8- thymocytes exhibited a severe block in proliferation but still
differentiated into mature T cells. GADS- thymocytes failed to respond to CD3
cross-linking in vivo and were impaired in positive and negative selection.
Immunoprecipitation experiments revealed that the association between SLP-76 and
LAT was uncoupled in GADS- thymocytes. These observations indicate that GADS is
a critical adaptor for CD3 signaling.
PMID: 11239162 [PubMed - indexed for MEDLINE]
Gads(GRAP2) has a role for homeostatic proliferaction in B cells.
1: Eur J Immunol. 2005 Apr;35(4):1184-92.
Expression and function of the adaptor protein Gads in murine B cells.
Yankee TM, Draves KE, Clark EA.
Nearly all hematopoietic receptors are dependent on adaptor proteins for the
activation of downstream signaling pathways. The Gads adaptor protein is
expressed in many hematopoietic tissues, including bone marrow, lymph node, and
spleen. Using intracellular staining, we detected Gads protein in a number
cells, including B cells, T cells, NK cells, monocytes, and plasmacytoid DC, but
not in macrophages, neutrophils, or monocyte-derived DC. In the B cell
compartment, Gads was first expressed after immature B cells leave the bone
marrow and was down-regulated after B cell antigen receptor (BCR) ligation.
Female Gads(-/-) mice had increased numbers of splenic B cells, as compared to
female Gads(+/+) mice, suggesting a role for Gads in B cell homeostasis.
Although B cell production and turnover of splenic B cell subsets appeared
normal in Gads(-/-) mice, homeostatic proliferation was significantly impaired
in Gads(-/-) B cells. Whereas BCR ligation can induce apoptosis in wild-type
transitional stage 1 (T1) B cells, Gads(-/-) T1 B cells were resistant to
BCR-induced apoptosis. Gads(-/-) B cells also showed increased BCR-mediated
calcium mobilization. We conclude that Gads may have a negative regulatory role
in signaling through survival pathways, and is necessary for normal homeostatic
proliferation in B cells.
PMID: 15761845 [PubMed - indexed for MEDLINE]
Grap negatively regulates T-cell proliferation.
1: Mol Cell Biol. 2002 May;22(10):3230-6.
Grap negatively regulates T-cell receptor-elicited lymphocyte proliferation and
interleukin-2 induction.
Shen R, Ouyang YB, Qu CK, Alonso A, Sperzel L, Mustelin T, Kaplan MH, Feng GS.
Program in Signal Transduction Research, The Burnham Institute, La Jolla,
California 92037, USA.
Grb-2-related adaptor protein (Grap) is a Grb2-like SH3-SH2-SH3 adaptor protein
with expression restricted to lymphoid tissues. Grap(-/-) lymphocytes isolated
from targeted Grap-deficient mice exhibited enhanced proliferation,
interleukin-2 production, and c-fos induction in response to mitogenic T-cell
receptor (TCR) stimulation, compared to wild-type cells. Ectopic expression of
Grap led to a suppression of Elk-1-directed transcription induced by the Ras/Erk
pathway, without having effects on gene expression mediated by Jnk and p38
mitogen-activated protein kinases. Together, these data suggest that Grap,
unlike Grb2, acts as a negative regulator of TCR-stimulated intracellular
signaling by downregulating signal relay through the Ras/Erk pathway.
PMID: 11971956 [PubMed - indexed for MEDLINE]
Gab2 is a substrate of ZAP-70 and functions as a switch molecule toward inhibition of TCR signal transuduction.
1: J Biol Chem. 2001 Nov 30;276(48):45175-83. Epub 2001 Sep 25.
Docking protein Gab2 is phosphorylated by ZAP-70 and negatively regulates T cell
receptor signaling by recruitment of inhibitory molecules.
Yamasaki S, Nishida K, Hibi M, Sakuma M, Shiina R, Takeuchi A, Ohnishi H, Hirano
T, Saito T.
Molecular Genetics, Chiba University Graduate School of Medicine, Chiba
260-8670, Japan.
To maintain various T cell responses and immune equilibrium, activation signals
triggered by T cell antigen receptor (TCR) must be regulated by inhibitory
signals. Gab2, an adaptor protein of the insulin receptor substrate-1 family,
has been shown to be involved in the downstream signaling from cytokine
receptors. We investigated the functional role of Gab2 in TCR-mediated signal
transduction. Gab2 was phosphorylated by ZAP-70 and co-precipitated with
phosphoproteins, such as ZAP-70, LAT, and CD3zeta, upon TCR stimulation.
Overexpression of Gab2 in Jurkat cells or antigen-specific T cell hybridomas
resulted in the inhibition of NF-AT activation, interleukin-2 production, and
tyrosine phosphorylation. The structure-function relationship of Gab2 was
analyzed by mutants of Gab2. The Gab2 mutants lacking SHP-2-binding sites mostly
abrogated the inhibitory activity of Gab2, but its inhibitory function was
restored by fusing to active SHP-2 as a chimeric protein. A mutant with
defective phosphatidylinositol 3-kinase binding capacity also impaired the
inhibitory activity, and the pleckstrin homology domain-deletion mutant revealed
a crucial function of the pleckstrin homology domain for localization to the
plasma membrane. These results suggest that Gab2 is a substrate of ZAP-70 and
functions as a switch molecule toward inhibition of TCR signal transduction by
mediating the recruitment of inhibitory molecules to the TCR signaling complex.
PMID: 11572860 [PubMed - indexed for MEDLINE]
B cell signaling causes tyrosine phosphorylation of Gab1, and in turn SHP2 bind to Gab1
Gab1 phosophorylation potentiate the phosphorylation of Akt, PI3K-dependent response.
1: J Biol Chem. 2001 Apr 13;276(15):12257-65. Epub 2001 Jan 22.
The Gab1 docking protein links the b cell antigen receptor to the
phosphatidylinositol 3-kinase/Akt signaling pathway and to the SHP2 tyrosine
phosphatase.
Ingham RJ, Santos L, Dang-Lawson M, Holgado-Madruga M, Dudek P, Maroun CR, Wong
AJ, Matsuuchi L, Gold MR.
Departments of Microbiology and Immunology and Zoology, University of British
Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
B cell antigen receptor (BCR) signaling causes tyrosine phosphorylation of the
Gab1 docking protein. This allows phosphatidylinositol 3-kinase (PI3K) and the
SHP2 tyrosine phosphatase to bind to Gab1. In this report, we tested the
hypothesis that Gab1 acts as an amplifier of PI3K- and SHP2-dependent signaling
in B lymphocytes. By overexpressing Gab1 in the WEHI-231 B cell line, we found
that Gab1 can potentiate BCR-induced phosphorylation of Akt, a PI3K-dependent
response. Gab1 expression also increased BCR-induced tyrosine phosphorylation of
SHP2 as well as the binding of Grb2 to SHP2. We show that the pleckstrin
homology (PH) domain of Gab1 is required for BCR-induced phosphorylation of Gab1
and for Gab1 participation in BCR signaling. Moreover, using confocal
microscopy, we show that BCR ligation can induce the translocation of Gab1 from
the cytosol to the plasma membrane and that this requires the Gab1 PH domain as
well as PI3K activity. These findings are consistent with a model in which the
binding of the Gab1 PH domain to PI3K-derived lipids brings Gab1 to the plasma
membrane, where it can be tyrosine-phosphorylated and then act as an amplifier
of BCR signaling.
PMID: 11278704 [PubMed - indexed for MEDLINE]
RasGRP1 mediates Ras activation following TCR stimulatioin.
RasGRP1 and RasGRP3 induces RAS activation in B-cell to response to T-cell stimulation.
1: Immunol Lett. 2006 May 15;105(1):77-82. Epub 2006 Feb 20.
The role of RasGRPs in regulation of lymphocyte proliferation.
Coughlin JJ, Stang SL, Dower NA, Stone JC.
Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada T6G
2H7.
RasGRP1 links TCR signaling to Ras in T cells, while both RasGRP1 and RasGRP3
link BCR signaling to Ras in B cells. T cells deficient in RasGRP1 have
defective proliferative responses as do B cells deficient in both RasGRP1 and
RasGRP3, confirming the importance of Ras activation in lymphocyte
proliferation. While aged Rasgrp1-/- mice develop late-onset autoimmunity
characterized by splenomegaly and the presence of anti-nuclear antibodies (ANA),
the additional loss of RasGRP3 expression inhibits this phenotype. We show here
that the autoimmunity in Rasgrp1-/- mice is T cell dependent. Compared to
wildtype, Rasgrp1-/- T cells induce greater in vitro B cell proliferation that
is due, at least in part, to increased production of interleukin-4 (IL-4).
Rasgrp1 Rasgrp3 double mutant B cells are less responsive to this T cell
stimulation. The reduced double mutant B cell proliferative response was
paralleled by decreased induction of cyclin D2 upon stimulation with IL-4 and
anti-IgM. Taken together these results suggest that double mutant mice fail to
generate autoimmunity due to their decreased B cell cyclin D2 accumulation, and
thus proliferation, in response to the elevated levels of IL-4 produced by
mutant T cells.
PMID: 16530850 [PubMed - indexed for MEDLINE]
Grb2-hSos1-PLCgamma1-p36/p38-ZAP70 complexes localize in the vicinity of TCR-zeta
1: J Biol Chem. 1995 Aug 4;270(31):18428-36.
Ligation of the T-cell antigen receptor (TCR) induces association of hSos1,
ZAP-70, phospholipase C-gamma 1, and other phosphoproteins with Grb2 and the
zeta-chain of the TCR.
Nel AE, Gupta S, Lee L, Ledbetter JA, Kanner SB.
Department of Medicine, UCLA School of Medicine 90024, USA.
Signaling by the T-cell antigen receptor (TCR) involves both phospholipase C
(PLC)-gamma 1 and p21ras activation. While failing to induce Shc/Grb2
association, ligation of the TCR/CD3 receptor in Jurkat T-cells induced
hSos1-Grb2 complexes. In addition to hSos1, Grb2 participates in the formation
of a tyrosine phosphoprotein complex that includes 145-, 95-, 70-, 54-, and
36-38-kDa proteins. p145 was identified as PLC-gamma 1 and p70 as the protein
tyrosine kinase, ZAP-70. Although of the same molecular weight, p95 was not
recognized by an anti-serum to p95 Vav. The SH2 domains of Grb2 and PLC-gamma 1
were required for the formation of this protein complex. In anti-CD3-treated
cells, Grb2 redistributed from the cytosol to a particulate cell compartment
along with p36/p38, ZAP-70, and PLC-gamma 1. Part of the Grb2 complex associated
with the particulate compartment could be extracted with Nonidet P-40, while the
rest was Nonidet P-40 insoluble. In both the detergent-soluble and -insoluble
fractions, Grb2 coimmunoprecipitated with the zeta-chain of the TCR. Taken
together, these results indicate that anti-CD3 induces Grb2-hSos1-PLC-gamma
1-p36/p38-ZAP70 complexes, which localize in the vicinity of TCR-zeta.
PMID: 7629168 [PubMed - indexed for MEDLINE]
Gads(Grap2) plays an important role in T-cell signaling via its association with SLP-76 and LAT.
1: Curr Biol. 1999 Jan 28;9(2):67-75.
The hematopoietic-specific adaptor protein gads functions in T-cell signaling
via interactions with the SLP-76 and LAT adaptors.
Liu SK, Fang N, Koretzky GA, McGlade CJ.
Department of Medical Biophysics, University of Toronto, The Arthur and Sonia
Labatt
Brain Tumour Research Centre, Hospital for Sick Children, Research
Institute, 555 University Ave, Toronto, Ontario M5G 1X8, Canada.
BACKGROUND: The adaptor protein Gads is a Grb2-related protein originally
identified on the basis of its interaction with the tyrosine-phosphorylated form
of the docking protein Shc. Gads protein expression is restricted to
hematopoietic tissues and cell lines. Gads contains a Src homology 2 (SH2)
domain, which has previously been shown to have a similar binding specificity to
that of Grb2. Gads also possesses two SH3 domains, but these have a distinct
binding specificity to those of Grb2, as Gads does not bind to known Grb2 SH3
domain targets. Here, we investigated whether Gads is involved in T-cell
signaling. RESULTS: We found that Gads is highly expressed in T cells and that
the SLP-76 adaptor protein is a major Gads-associated protein in vivo. The
constitutive interaction between Gads and SLP-76 was mediated by the
carboxy-terminal SH3 domain of Gads and a 20 amino-acid proline-rich region in
SLP-76. Gads also coimmunoprecipitated the tyrosine-phosphorylated form of the
linker for activated T cells (LAT) adaptor protein following cross-linking of
the T-cell receptor; this interaction was mediated by the Gads SH2 domain.
Overexpression of Gads and SLP-76 resulted in a synergistic augmentation of
T-cell signaling, as measured by activation of nuclear factor of activated T
cells (NFAT), and this cooperation required a functional Gads SH2 domain.
CONCLUSIONS: These results demonstrate that Gads plays an important role in
T-cell signaling via its association with SLP-76 and LAT. Gads may promote
cross-talk between the LAT and SLP-76 signaling complexes, thereby coupling
membrane-proximal events to downstream signaling pathways.
PMID: 10021361 [PubMed - indexed for MEDLINE]
Lck is required for normal signal transduction through the TCR.
1: Cell. 1992 Aug 21;70(4):585-93.
Genetic evidence for the involvement of the lck tyrosine kinase in signal
transduction through the T cell antigen receptor.
Straus DB, Weiss A.
Howard Hughes Medical Institute, Department of Medicine, University of
California, San Francisco 94143.
Signaling through the T cell antigen receptor (TCR) results both in rapid
increases in tyrosine phosphorylation on a number of proteins and in the
activation of the phosphatidylinositol pathway. It is not clear how stimulation
of the TCR leads to these signaling events. Mutants of the Jurkat T cell line
have been previously isolated that fail to show increases in calcium following
receptor stimulation. Analysis of one of these mutants, JCaM1, which is
defective in the induction of tyrosine phosphorylation, revealed a defect in the
expression of functional lck tyrosine kinase. The lack of lck activity was
caused in part by a splicing defect. Expression of the lck cDNA in JCaM1
restores the ability of the cell to respond to TCR stimulation. These results
indicate that lck is required for normal signal transduction through the TCR.
PMID: 1505025 [PubMed - indexed for MEDLINE]
ZAP-70 plays crucial roles in T-cell activation and development.
Syk triggers cellular activation in T-cell.
1: Mol Cell Biol. 1998 Mar;18(3):1388-99.
Genetic evidence for differential coupling of Syk family kinases to the T-cell
receptor: reconstitution studies in a ZAP-70-deficient Jurkat T-cell line.
Williams BL, Schreiber KL, Zhang W, Wange RL, Samelson LE, Leibson PJ, Abraham
RT.
Department of Immunology, Mayo Clinic, Rochester, Minnesota 55905, USA.
T-cell antigen receptor (TCR) engagement activates multiple protein tyrosine
kinases (PTKs), including the Src family member, Lck, and the Syk-related PTK,
ZAP-70. Studies in ZAP-70-deficient humans have demonstrated that ZAP-70 plays
crucial roles in T-cell activation and development. However, progress toward a
detailed understanding of the regulation and function of ZAP-70 during TCR
signaling has been hampered by the lack of a suitable T-cell model for
biochemical and genetic analyses. In this report, we describe the isolation and
phenotypic characterization of a Syk- and ZAP-70-negative somatic mutant derived
from the Jurkat T-cell line. The P116 cell line displays severe defects in
TCR-induced signaling functions, including protein tyrosine phosphorylation,
intracellular Ca2+ mobilization, and interleukin-2 promoter-driven
transcription. These signaling defects were fully reversed by reintroduction of
catalytically active versions of either Syk or ZAP-70 into the P116 cells.
However, in contrast to ZAP-70 expression, Syk expression triggered a
significant degree of cellular activation in the absence of TCR ligation.
Transfection experiments with ZAP-70-Syk chimeric proteins indicated that both
the amino-terminal regulatory regions and the carboxy-terminal catalytic domains
of Syk and ZAP-70 contribute to the distinctive functional properties of these
PTKs. These studies underscore the crucial role of ZAP-70 in TCR signaling and
offer a powerful genetic model for further analyses of ZAP-70 regulation and
function in T cells.
PMID: 9488454 [PubMed - indexed for MEDLINE]
最終更新：2006年12月13日 21:35
