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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The selective induction of effector functions of a T-cell clone (DB14), specific to pigeon cytochrome c 43-58 (p 43-58) and restricted to I-Ab, was analyzed using a professional antigen-presenting cell, B hybridoma (Th 2.58), and various non-professional antigen-presenting cells (APC), L cells transfected with I-Ab (I-Ab L cells), a medullary thymic epithelial cell line (m-TEC) and a cortical thymic epithelial cell line (c-TEC). The m-
TEC
, and c-
TEC
expressed I-Ab upon induction with interferon gamma (IFN-gamma). When stimulated with p 43-58 in the presence of I-Ab L cells as well as Th 2.58 cells, the DB14 cells showed marked proliferation and, after 18 hr of culturing, exhibited significant cytotoxicity against the APC. By contrast, in the presence of m, c-
TEC
, the DB14 cells showed neither proliferation nor cytotoxicity against these
TEC
but exhibited considerable detachment activity towards them. Furthermore, DB14 cells became expressed activation markers
CD69
or CD44) following stimulation with p 43-58 plus m-TEC or c-TEC. The addition of rIL-2 to the culture of DC14 cells, p 43-58 and m-TEC or c-TEC, restored the proliferative responses. However, it was shown that anergy was not involved in the negligible proliferative responses of DB14 cells after stimulation with p 43-58 plus m, c-TEC. The present findings indicate that differences in APC functions are present among the non-professional APC and suggest that the selective induction of T-cell functions can be achieved using the appropriate non-professional APC. The characteristic activation of T cells by
TEC
may be related to their functional roles in situ.
...
PMID:Detachment activity but not cytotoxicity induced in a T-cell clone following antigen presentation in the presence of thymic epithelial cells. 908 68
Selective induction of effector functions in a T cell clone, DB14, specific for pigeon cytochrome c 43-58 (p43-58) and restricted to I Ab was analyzed using professional antigen presenting cells (APC), B hybridoma (Th2.58), and various non professional APC, L cells transfected with I Ab (I-Ab L cells), a medullary thymic epithelial cell line (m-TEC) and a cortical thymic epithelial cell line (c-TEC). The m-
TEC
and c-
TEC
(m, c-TEC) expressed I-Ab after culturing with interferon-gamma (IFN-gamma). When stimulated with p43-58 in the presence of I-Ab L cells as well as Th2.58 cells, the DB14 cells showed marked proliferation and exhibited significant cytotoxicity against these APC after 18 hr of culture. By contrast, in the presence of m, c-
TEC
the DB14 cells showed neither proliferation nor cytotoxicity against these
TEC
but exhibited considerable detachment activity against them. Furthermore DB14 cells became expressed activation markers (
CD69
and CD44) after antigen (p43-58) stimulation with m-
TEC
or c-
TEC
. Addition of rIL-2 to the culture of DB14 cells, p43-58 and m, c-
TEC
restored the proliferative responses. However, it was shown that anergy was not involved in the lack of proliferative response of DB14 cells after antigen stimulation with m, c-
TEC
. The present findings indicate that differences in APC function are present among non-professional APC and suggest that the selective induction of T cell functions can be achieved using appropriate non-professional APC. The characteristic activation of T cells by
TEC
may be related to their functional roles in situ.
...
PMID:[Selective induction of effector functions in a T cell clone following antigen presentation in the presence of thymic epithelial cells]. 914 12
LCK
is a non-receptor protein tyrosine kinase required for signal transduction via the T-cell antigen receptor (TCR).
LCK
N-terminus is S-acylated on Cys3 and Cys5, in addition to its myristoylation on Gly2. Here the role of S-acylation in
LCK
function was examined. Transient transfection of COS-18 cells, which express a CD8-zeta chimera on their surface, revealed that
LCK
mutants that were singly S-acylated were able to target to the plasma membrane and to phosphorylate CD8-zeta. A non-S-acylated
LCK
mutant did not target to the plasma membrane and failed to phosphorylate CD8-zeta, although it was catalytically active. Fusion of non-S-acylated
LCK
to a transmembrane protein, CD16:7, allowed its plasma membrane targeting and also phosphorylation of CD8-zeta when expressed in COS-18 cells. Thus S-acylation targets
LCK
to the plasma membrane where it can interact with the TCR. When expressed in
LCK
-negative JCam-1.6 T cells, delocalized, non-S-acylated
LCK
was completely non-functional. Singly S-acylated
LCK
mutants, which were expressed in part at the plasma membrane, efficiently reconstituted the induced association of phospho-zeta with ZAP-70 and intracellular Ca2+ fluxes triggered by the TCR. Induction of the late signalling proteins,
CD69
and NFAT, was also reconstituted, although at reduced levels. The transmembrane
LCK
chimera also supported the induction of tyrosine phosphorylation and Ca2+ flux by the TCR in JCam-1.6 cells. However, induction of ERK MAP kinase was reduced and the chimera was incapable of reconstituting induced
CD69
or NFAT expression. These data indicate that
LCK
must be attached to the plasma membrane via dual acylation of its N-terminus to function properly in TCR signalling.
...
PMID:S-acylation of LCK protein tyrosine kinase is essential for its signalling function in T lymphocytes. 930 40
We have previously shown that a tyrosine to leucine replacement in the transmembrane region of T cell receptor (TCR)-beta results in a deficient induction of CD95-L and apoptosis upon TCR triggering in a transfected T cell line. By contrast, interleukin (IL)-2 production and the expression of CD25 and
CD69
were normally induced. Since the mutation in TCR-beta also resulted in impaired association of CD3-zeta, it was proposed that this chain is specifically required for the induction of apoptosis. We now show that the deficient induction of CD95-L and apoptosis does not derive from a general lower production of second messengers, since intracellular Ca2+ fluxes and tyrosine phosphorylation of total proteins were elicited at wild-type levels. Unlike in T cell clones stimulated with partial agonists, both p21 and p18 forms of tyrosine-phosphorylated CD3-zeta were detected, although the overall level of tyrosine-phosphorylated CD3-zeta was low. More strikingly, inducible association of
ZAP70
to CD3-zeta was strongly inhibited, despite a normal induction of
ZAP70
tyrosine phosphorylation. Finally,
ZAP70
was not concentrated near the plasma membrane in the apoptosis-deficient cells. These results suggest that CD3-zeta is necessary for engagement of a specific signaling pathway leading to CD95-L expression that also needs the recruitment of
ZAP70
.
...
PMID:T cell receptor (TCR) engagement in apoptosis-defective, but interleukin 2 (IL-2)-producing, T cells results in impaired ZAP70/CD3-zeta association. 954 30
One of the earliest recognized defects of B cells carrying the xid mutation in the gene encoding for
Bruton's tyrosine kinase
(
Btk
) was their inability to proliferate in response to anti-immunoglobulin plus interleukin (IL)-4 stimulation. Previous attempts to define the stage at which this proliferative block occurred using xid B cells provided dissimilar results. We decided to reinvestigate this question using B cells from C57BL/6-
Btk
-protein-deficient (BtkM) mice. Upon stimulation with anti-IgM and IL-4, BtkM cells increase in size and up-regulate early activation markers such as
CD69
and B7-2, however, they do not progress into the cell cycle further than a very early G1 stage. They down-regulate the cyclin-dependent kinase (cdk) inhibitor p27 to some extent but fail to up-regulate the G1-phase cyclins D2 and E and the retinoblastoma protein (pRb) remains hypo-phosphorylated. While approximately 25% of the wild-type cells enter S phase after 36 h stimulation, only 1% of the BtkM cells do so. The proliferative responsiveness of the BtkM cells is restored when the phorbol ester phorbol 12,13-di-butyrate (PDBu) is added to the anti-IgM plus IL-4 cultures. Collectively, our data demonstrate that a dramatically reduced frequency of responsive cells underlies the low proliferation of anti-IgM plus IL-4-stimulated
Btk
-deficient B cells and point towards an early block in the G1 phase due to inadequate activation of a pathway that regulates PKC activation.
...
PMID:Bruton's tyrosine-kinase-deficient murine B lymphocytes fail to enter S phase when stimulated with anti-immunoglobulin plus interleukin-4. 1007 19
The Wiskott-Aldrich syndrome protein (WASp) has been implicated in modulation of lymphocyte activation and cytoskeletal reorganization. To address the mechanisms whereby WASp subserves such functions, we have examined WASp roles in lymphocyte development and activation using mice carrying a WAS null allele (WAS(-)(/)(-)). Enumeration of hemopoietic cells in these animals revealed total numbers of thymocytes, peripheral B and T lymphocytes, and platelets to be significantly diminished relative to wild-type mice. In the thymus, this abnormality was associated with impaired progression from the CD44(-)CD25(+) to the CD44(-)CD25(-) stage of differentiation. WASp-deficient thymocytes and T cells also exhibited impaired proliferation and interleukin (IL)-2 production in response to T cell antigen receptor (TCR) stimulation, but proliferated normally in response to phorbol ester/ionomycin. This defect in TCR signaling was associated with a reduction in TCR-evoked upregulation of the early activation marker
CD69
and in TCR-triggered apoptosis. While induction of TCR-zeta,
ZAP70
, and total protein tyrosine phosphorylation as well as mitogen-activated protein kinase (MAPK) and stress-activated protein/c-Jun NH(2)-terminal kinase (SAPK/JNK) activation appeared normal in TCR-stimulated WAS(-)(/)(-) cells, TCR-evoked increases in intracellular calcium concentration were decreased in WASp-deficient relative to wild-type cells. WAS(-)(/)(-) lymphocytes also manifested a marked reduction in actin polymerization and both antigen receptor capping and endocytosis after TCR stimulation, whereas WAS(-)(/)(-) neutrophils exhibited reduced phagocytic activity. Together, these results provide evidence of roles for WASp in driving lymphocyte development, as well as in the translation of antigen receptor stimulation to proliferative or apoptotic responses, cytokine production, and cytoskeletal rearrangement. The data also reveal a role for WASp in modulating endocytosis and phagocytosis and, accordingly, suggest that the immune deficit conferred by WASp deficiency reflects the disruption of a broad range of cellular behaviors.
...
PMID:Antigen receptor-induced activation and cytoskeletal rearrangement are impaired in Wiskott-Aldrich syndrome protein-deficient lymphocytes. 1054 4
The purpose of this study was to determine whether the JAK pathway is involved in eosinophil activation and survival through IFN-gamma receptor signalling in human peripheral eosinophils. Eosinophils were purified from the blood of six atopic disease patients by anti-CD16 magnetic bead-negative selection. IFN-gamma significantly up-regulated survival and
CD69
expression in 24-48 h cultured eosinophils. Further, IFN-gamma induced tyrosine phosphorylation of
JAK2
in eosinophils, as indicated by Western blot analysis. Finally, the specific
JAK2
inhibitor AG-490 inhibited the tyrosine phosphorylation of
JAK2
, IFN-gamma-induced survival and
CD69
expression in eosinophils. In conclusion, these results indicate that IFN-gamma induces eosinophil survival and
CD69
expression through the activation of
JAK2
in peripheral eosinophils, suggesting that
JAK2
may play a significant role in eosinophil regulation by IFN-gamma-IFN-gammaR interaction.
...
PMID:Role of JAK2 signal transductional pathway in activation and survival of human peripheral eosinophils by interferon-gamma (IFN-gamma). 1059 49
Engagement of the B cell receptor (BCR) leads to the activation of tyrosine kinases and other signaling molecules that ultimately determine the type and magnitude of the B lymphocyte's cellular response. The adaptor protein BLNK/SLP-65 plays a pivotal role in BCR signal transduction by coupling Syk activation to downstream elements such as Grb2, phospholipase C-gamma, Vav and Nck. We have generated BLNK(-/-) mice to determine the physiological role of this protein in B cell development and activation. BLNK(-/-) mice exhibit an incomplete block in B cell development with a severe inhibition of pro-B to pre-B cell differentiation. BLNK(-/-) sIgM(+) cells can develop, seed the peripheral lymphoid tissues and accumulate in numbers overtime. However, these mutant B cells failed to mature and are non-responsive to BCR cross-linking in terms of proliferation and up-regulation of activation markers such as
CD69
and CD86 (B7-2). In addition, the CD5(+) subset of B cells is absent. The immune response to T cell-independent antigen but not T cell-dependent antigen is also impaired. Overall, the phenotype of BLNK(-/-) mice bears a striking resemblance to that of xid mice which is the murine model of human XLA that has a mutation in
Bruton's tyrosine kinase
. This raises the interesting possibility that mutation in BLNK/SLP-65 may be responsible for certain human immunodeficiencies.
...
PMID:B cell development and activation defects resulting in xid-like immunodeficiency in BLNK/SLP-65-deficient mice. 1070 Apr 74
The purpose of this study was to determine whether interferon-gamma (IFN-gamma) induced
CD69
expression by eosinophil precursors. Eosinophil precursors were induced from CD34+ cord blood cells using recombinant human interleukin-3 (IL-3) and interleukin-5 (IL-5). On day 14 of culture, cells constitutively expressed
CD69
and the IFN-gamma receptor (IFN-gammaR). Stimulation with IFN-gamma for 24 h did not affect IFN-gammaR expression by the cells. On the other hand, IFN-gamma significantly upregulated
CD69
expression by the precursors after 24 h of incubation. A specific
JAK2
inhibitor (AG-490) caused a concentration-dependent suppression of IFN-gamma-induced
CD69
expression by the precursors. In conclusion, these results indicate that IFN-gamma induces
CD69
expression by eosinophil precursors via the activation of
JAK2
.
...
PMID:Regulation of CD69 expression on eosinophil precursors by interferon-gamma. 1086 4
Peripheral T lymphocyte activation in response to TCR/CD3 stimulation is reduced in type 1 diabetic patients. To explore the basis of this deficiency, a comprehensive analysis of the signal transduction pathway downstream of the TCR/CD3 complex was performed for a cohort of patients (n = 38). The main result of the study shows that T cell hyporesponsiveness is positively correlated with a reduced amount of p56(lck) in resting T lymphocytes. Upon CD3-mediated activation, this defect leads to a hypophosphorylation of the CD3zeta-chain and few other polypeptides without affecting the recruitment of
ZAP70
. Other downstream effectors of the TCR/CD3 transduction machinery, such as phosphatidylinositol 3-kinase p85alpha, p59(fyn), linker for activation of T cells (LAT), and phospholipase C-gamma1, are not affected. In some patients, the severity of this phenotypic deficit could be linked to low levels of p56(lck) mRNA and resulted in the failure to efficiently induce the expression of the
CD69
early activation marker. We propose that a primary deficiency in human type 1 diabetes is a defect in TCR/CD3-mediated T cell activation due to the abnormal expression of the p56(lck) tyrosine kinase.
...
PMID:Specific deficiency of p56lck expression in T lymphocytes from type 1 diabetic patients. 1106 48
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