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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 present minireview describes experiments carried out, in short-term crush-operated rat nerves, using immunofluorescence and cytofluorimetric scanning techniques to study endogenous substances in anterograde and retrograde fast axonal transport. Vesicle membrane components
p38
(synaptophysin) and SV2 are accumulating on both sides of a crush, but a larger proportion of
p38
(about 3/4) than of SV2 (about 1/2) is recycling toward the cell body, compared to the amount carried with anterograde transport. Matrix peptides, such as CGRP, ChRA, VIP, and DBH are recycling to a minor degree, although only 10-20% of surface-associated molecules, such as synapsins and kinesin, appear to recycle. The described methodological approach to study the composition of organelles in fast axonal transport, anterograde as compared to retrograde, is shown to be useful for investigating neurobiological processes. We make use of the "in vivo chromatography" process that the fast axonal transport system constitutes. Only substances that are in some way either stored in, or associated with, transported organelles can be clearly observed to accumulate relative to the crush region. Emphasis in this paper was given to the synapsins, because of diverging results published concerning the degree of affiliation with various neuronal organelles. Our previously published results have indicated that in the living axons the
SYN
I is affiliated with mainly anterogradely fast transported organelles. Therefore, some preliminary, previously unpublished results on the accumulations of the four different synapsins (
SYN
Ia,
SYN
Ib,
SYN
IIa, and
SYN
IIb), using antisera specific for each of the four members of the synapsin family, are described. It was found that
SYN
Ib clearly has a stronger affiliation to anterogradely transported organelles than
SYN
Ia, and that both
SYN
IIa and
SYN
IIb are bound to some degree to transported organelles.
...
PMID:Organelles in fast axonal transport. What molecules do they carry in anterograde vs retrograde directions, as observed in mammalian systems? 128 29
The presence of calcitonin-gene-related peptide (CGRP) and chromogranin A was investigated in the developing rat (E18-adult) motor system, using immunofluorescence and confocal laser scanning, and compared with synaptic vesicle markers, synaptophysin and synapsin I. In lumbar motor perikarya CGRP-LI and Chr A-LI were present in high intensities in E18 and P1 perikarya in the anterior horn. With increasing age immunoreactivity decreased. Chr A-LI was sparse in the adult. In peroneal endplates,
p38
-LI and
SYN
I-LI were present in all stages, including E18. Peptide-LI was very weak or absent in early stages (E18 and P1), but abundant in P8 and P18, especially CGRP-LI, and decreased again in P32 and adult animals. These observations indicate that the peptides have precise functions during certain developmental stages, possibly related to synapse maturation, receptor concentration, and reduction of supernumerary endplates. Both peptides are rapidly transported anterogradely in adult motor axons, and may serve physiological functions also in the adult.
...
PMID:Development of calcitonin-gene-related peptide, chromogranin A, and synaptic vesicle markers in rat motor endplates, studied using immunofluorescence and confocal laser scanning. 151 19
The distribution and axonal transport of cholinergic organelles has been studied in the rat motor system, using immunofluorescence methods and a cytofluorimetric technique for quantification of immunoreactive material. Crush-operated spinal roots and sympathectomized sciatic nerves were sectioned longitudinally and incubated with antisera against
p38
, SV2, CGRP, chromogranin A (Chr A), synapsin I (
SYN
I), and with RASVA (rabbit anti-synaptic vesicle antiserum). Motor endplates were also studied. It was observed that proximally accumulating organelles--i.e., organelles which were in transport distally in the axons--contained RASVA-like immunoreactivity (LI)
p38
, SV2, CGRP-LI, Chr A-LI, and
SYN
I-LI. Retrogradely transported organelles, however, contained only
p38
and SV2 in addition to RASVA-LI, but virtually no CGRP-LI, ChrA-LI, or
SYN
I-LI. It is suggested that the rapid axonal transport mechanism operates in the nerves like a chromatographic process, which allows the concentration in the axons, proximal or distal to the crush, of organelles in anterograde or retrograde transport, respectively. The technique of nerve crushes in combination with immunocytochemistry can therefore be used to investigate the biochemical composition of organelles in transit along the axon, and give information on neurobiological events occurring in these long processes leading to the nerve endings. In this study, biochemical differences between anterogradely and retrogradely transported cholinergic organelles in the motor neuron of the rat have been observed, and were related to suggested events in the endplate.
...
PMID:Rapid axonal transport as a chromatographic process: the use of immunocytochemistry of ligated nerves to investigate the biochemistry of anterogradely versus retrogradely transported organelles. 246 Feb 58
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: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. 762 68
We have found that insulin-like growth factor I (IGF-I) can protect fibroblasts from apoptosis induced by UV-B light. Antiapoptotic signalling by the IGF-I receptor depended on receptor kinase activity, as cells overexpressing kinase-defective receptor mutants could not be protected by IGF-I. Overexpression of a kinase-defective receptor which contained a mutation in the ATP binding loop functioned as a dominant negative and sensitized cells to apoptosis. The antiapoptotic capacity of the IGF-I receptor was not shared by other growth factors tested, including epidermal growth factor (EGF) and thrombin, although the cells expressed functional receptors for all the agonists. However, EGF was antiapoptotic for cells overexpressing the EGF receptor, and expression of activated pp60v-src also was protective. There was no correlation between protection from apoptosis and activation of mitogen-activated protein kinase,
p38
/HOG1, or p70S6 kinase. On the other hand, protection by any of the tyrosine kinases against UV-induced apoptosis was blocked by wortmannin, implying a role for phosphatidylinositol 3-kinase (PI3 kinase). To test this, we transiently expressed constitutively active or kinase-dead PI3 kinase and found that overexpression of activated phosphatidylinositol 3-kinase (PI3 kinase) was sufficient to provide protection against apoptosis. Because Akt/
PKB
is believed to be a downstream effector for PI3 kinase, we also examined the role of this serine/threonine protein kinase in antiapoptotic signalling. We found that membrane-targeted Akt was sufficient to protect against apoptosis but that kinase-dead Akt was not. We conclude that the endogenous IGF-I receptor has a specific antiapoptotic signalling capacity, that overexpression of other tyrosine kinases can allow them also to be antiapoptotic, and that activation of PI3 kinase and Akt is sufficient for antiapoptotic signalling.
...
PMID:Antiapoptotic signalling by the insulin-like growth factor I receptor, phosphatidylinositol 3-kinase, and Akt. 903 87
Mast cells derived from
Bruton's tyrosine kinase
(
Btk
)-defective xid or btk null mice showed greater expansion in culture containing interleukin-3 (IL-3) than those from wild-type (wt) mice. Although the proliferative response to IL-3 was not significantly different between the wt and xid mast cells, xid and btk null mast cells died by apoptosis more slowly than their wt counterparts upon IL-3 deprivation. Consistent with these findings, the apoptosis-linked c-Jun N-terminal kinase/stress-activated protein kinase (JNK) activity was compromised in these btk-mutated cells upon Fc(epsilon)RI crosslinking or upon stimulation with IL-3 or with stem cell factor.
p38
activity was less severely, but significantly, affected by btk mutation, whereas extracellular signal-regulated kinases were not affected by the same mutation.
Btk
-mediated regulation of apoptosis and JNK activity was confirmed by reconstitution of btk null mutant mast cells with the wt btk cDNA. Furthermore, growth factor withdrawal induced the activation and sustained activity of JNK in wt mast cells, while JNK activity was consistently lower in btk-mutated mast cells. These results support the notion that
Btk
regulates apoptosis through the JNK activation.
...
PMID:Bruton's tyrosine kinase regulates apoptosis and JNK/SAPK kinase activity. 910 83
Detachment of epithelial cells from the extracellular matrix leads to induction of programmed cell death, a process that has been termed "anoikis." It has been reported recently that detachment of MDCK cells from matrix results in activation of Jun-NH2-terminal kinases (JNKs) and speculated that these stress activated protein kinases play a causal role in the induction of anoikis (Frisch, S.M., K. Vuori, D. Kelaita, and S. Sicks. 1996. J. Cell Biol. 135:1377-1382). We report here that although JNK is activated by detachment of normal MDCK cells, study of cell lines expressing activated signaling proteins usually controlled by Ras shows that stimulation of JNK fails to correlate with induction of anoikis. Activated phosphoinositide 3-OH kinase and activated
PKB
/Akt protect MDCK cells from detachment-induced apoptosis without suppressing JNK activation. Conversely, activated Raf and dominant negative SEK1, a JNK kinase, attenuate detachment-induced JNK activation without protecting from apoptosis. zVAD-fmk, a peptide inhibitor of caspases, prevents MDCK cell anoikis without affecting JNK activation.
p38
, a related stress-activated kinase, is also stimulated by detachment from matrix, but inhibition of this kinase with SB 203580 does not protect from anoikis. It is therefore unlikely that either JNK or
p38
play a direct role in detachment-induced programmed cell death in epithelial cells.
...
PMID:Lack of correlation between activation of Jun-NH2-terminal kinase and induction of apoptosis after detachment of epithelial cells. 936 19
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.
...
PMID:Btk function in B cell development and response. 969 87
The molecular signaling mechanisms by which muscle contractions lead to changes in glucose metabolism and gene expression remain largely undefined. We assessed whether exercise activates MAP kinase proteins (ERK1/2, SEK1, and p38 MAP kinase) as well as Akt and
PYK2
in skeletal muscle from healthy volunteers obtained during and after one-leg cycle ergometry at approximately 70% VO2max. Exercise led to a marked increase in ERK1/2 phosphorylation, which rapidly decreased to resting levels upon recovery. Exercise increased phosphorylation of SEK1 and p38 MAP kinase to a lesser extent than ERK1/2. In contrast to ERK1/2, p38 MAP kinase phosphorylation was increased in nonexercised muscle upon cessation of exercise. Phosphorylation of the transcription factor CREB was increased in nonexercised muscle upon cessation of exercise. Exercise did not activate Akt or increase tyrosine phosphorylation of
PYK2
. Thus, exercise has divergent effects on parallel MAP kinase pathways, of which only
p38
demonstrated a systemic response. However, our data do not support a role of Akt or
PYK2
in exercise/contraction-induced signaling in human skeletal. Activation of the different MAP kinase pathways by physical exercise appears to be important in the regulation of transcriptional events in skeletal muscle.
...
PMID:Divergent effects of exercise on metabolic and mitogenic signaling pathways in human skeletal muscle. 976 81
The receptors for the I1-3/IL-5/GM-CSF cytokine family are composed of a heterodimeric complex of a cytokine-specific alpha chain and a common beta chain (betac). Binding of IL-3/IL-5/GM-CSF to their respective receptors rapidly induces activation of multiple intracellular signalling pathways, including the Ras-Raf-ERK, the JAK/STAT, the phosphatidylinositol 3-kinase
PKB
, and the JNK/SAPK and
p38
signalling pathways. This review focuses on recent advancements in understanding how these different signalling pathways are activated by IL-3/IL-5/GM-CSF receptors, and how the individual pathways contribute to the pleiotropic effects of IL-3/IL-5/GM-CSF on their target cells, including proliferation, differentiation, survival, and effector functions.
...
PMID:Regulation of proliferation, differentiation and survival by the IL-3/IL-5/GM-CSF receptor family. 979 43
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