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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)
Flowering plants possess self-incompatibility (SI) mechanisms that promote outbreeding and thereby increase their genetic diversity. In the self-incompatible Brassicaceae, recognition and rejection of self-pollen is based on a receptor-ligand interaction between male and female SI determinants. A transmembrane receptor kinase (S locus Receptor Kinase,
SRK
) determines the SI specificity in stigmatic cells, whereas a pollen coat-localized ligand (S locus
Cysteine
-Rich, SCR) determines the SI specificity in pollen. During recent years, major advances have been made in the understanding of the molecular basis of self-pollen recognition by stigmatic cells. In this review, we will focus on evolutionary aspects of the SI system in Brassicaceae. We will describe how the study of the molecular aspect of SI, not only in the historical Brassica model but also in Arabidopsis species, has contributed to highlight certain aspects of evolution of SI in the Brassicaceae.
...
PMID:Molecular evolution of the s locus controlling mating in the brassicaceae. 1504 61
Several oncogene and tumor-suppressor gene products are known substrates for the calpain family of
cysteine
proteases, and calpain is required for transformation by v-src and tumor invasion. Thus, we have now addressed whether calpain is generally associated with transformation and how calpain contributes to oncogene function. Our results demonstrate that calpain activity is enhanced upon transformation induced by the v-Src, v-Jun, v-Myc, k-Ras, and v-Fos oncoproteins. Furthermore, elevated calpain activity commonly promotes focal adhesion remodelling, disruption of actin cytoskeleton, morphological transformation, and cell migration, although proteolysis of target substrates (such as
focal adhesion kinase
, talin, and spectrin) is differently specified by individual oncoproteins. Interestingly, v-Fos differs from other common oncoproteins in not requiring calpain activity for actin/adhesion remodelling or migration of v-Fos transformed cells. However, anchorage-independent growth of all transformed cells is sensitive to calpain inhibition. In addition, elevated calpain activity contributes to oncogene-induced apoptosis associated with transformation by v-Myc. Taken together, these studies demonstrate that calpain activity is necessary for full cellular transformation induced by common oncoproteins, but has distinct roles in oncogenic events induced by individual transforming proteins. Thus, targeting calpain activity may represent a useful general strategy for interfering with activated proto-oncogenes in cancer cells.
...
PMID:Calpain activity is generally elevated during transformation but has oncogene-specific biological functions. 1506 71
We describe a novel interaction between the disintegrin and
cysteine
-rich (DC) domains of ADAM12 and the integrin alpha7beta1. Integrin alpha7beta1 extracted from human embryonic kidney 293 cells transfected with alpha7 cDNA was retained on an affinity column containing immobilized DC domain of ADAM12. 293 cells stably transfected with alpha7 cDNA adhered to DC-coated wells, and this adhesion was partially inhibited by 6A11 integrin alpha7 function-blocking antibody. The X1 and the X2 extracellular splice variants of integrin alpha7 supported equally well adhesion to the DC protein. Integrin alpha7beta1-mediated cell adhesion to DC had different requirements for Mn2+ than adhesion to laminin. Furthermore, integrin alpha7beta1-mediated cell adhesion to laminin, but not to DC, resulted in efficient cell spreading and phosphorylation of
focal adhesion kinase
(
FAK
) at Tyr397. We also show that adhesion of L6 myoblasts to DC is mediated in part by the endogenous integrin alpha7beta1 expressed in these cells. Since integrin alpha7 plays an important role in muscle cell growth, stability, and survival, and since ADAM12 has been implicated in muscle development and regeneration, we postulate that the interaction between ADAM12 and integrin alpha7beta1 may be relevant to muscle development, function, and disease. We also conclude that laminin and the DC domain of ADAM12 represent two functional ligands for integrin alpha7beta1, and adhesion to each of these two ligands via integrin alpha7beta1 triggers different cellular responses.
...
PMID:Interaction of the disintegrin and cysteine-rich domains of ADAM12 with integrin alpha7beta1. 1524 59
Previously we have reported that thrombin induces inflammatory mediators in brain glial cells (Ryu et al. 2000. J Biol Chem 275:29955). In the present study, we found that thrombin induced a negative regulator of a cytokine signaling molecule, cytokine-induced SH2 protein (CIS), in rat brain astrocytes. In response to thrombin, CIS expression was increased at both the mRNA and protein levels. Although STAT5 is known to regulate CIS expression, thrombin did not activate STAT5, and inhibitors of
JAK2
(AG490) and
JAK3
(WHI-P97 and WHI-P154) had little effect on thrombin-induced CIS expression. In contrast, cytosolic phospholipase A(2) (cPLA(2)), cyclooxygenase (COX), and lipoxygenase (LO) play a role in CIS expression, since inhibitors of cPLA(2), cyclooxygenase (COX), and LO significantly reduced CIS expression. Reactive oxygen species (ROS) scavengers (N-acetyl-
cysteine
[NAC] and trolox) reduced thrombin-induced CIS expression, and inhibitors of COX and LO reduced ROS produced by thrombin. Furthermore, prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)), products of COX and LO, respectively, potentiated thrombin-induced CIS expression, indicating that ROS, and PGE(2) and LTB(4) generated by COX and LO, mediate CIS expression. Since interferon-gamma (IFN-gamma)-induced GAS-luciferase activity and tyrosine phosphorylation of STAT1 and STAT3 were lower in CIS-transfected cells compared to control vector-transfected cells, CIS could have anti-inflammatory activity. These data suggest that thrombin-stimulation of ROS and prostaglandin and leukotriene production via the cPLA(2), COX and LO pathways results in CIS expression. More importantly, CIS expression may be a negative feedback mechanism that prevents prolonged inflammatory responses.
...
PMID:Thrombin induces expression of cytokine-induced SH2 protein (CIS) in rat brain astrocytes: involvement of phospholipase A2, cyclooxygenase, and lipoxygenase. 1537 59
We have previously identified C1 domain-containing phosphatase and TENsin homologue (C1-TEN) as being an intracellular binding partner for Axl receptor tyrosine kinase (RTK). C1-TEN is a tensin-related protein that houses an N-terminal region with predicted structural similarity to PTEN. Here, we report our observations on the effects of ectopic expression of C1-TEN in HEK293 cells, which resulted in profound molecular and phenotypic changes. Stable expression of C1-TEN altered cellular morphology, with less cell spreading and weaker filamentous actin staining. Cells overexpressing C1-TEN were inhibited greatly in their proliferation and migration rates as compared with mock-transfected cells. Furthermore, serum starvation-induced apoptosis caused a twofold increase in caspase 3 activity in C1-TEN-overexpressing cells vs. mock cells. In addition, C1-TEN-overexpressing cells showed a markedly reduced phosphorylation of Akt/
PKB
kinase and its substrate GSK3, as well as reduced Akt enzymatic activity. No such effects on JNK were observed. Also, serum-stimulated activation of Akt was delayed in C1-TEN-overexpressing cells, while no difference in profile of ERK activation was observed. Furthermore, cells expressing a C1-TEN mutant where the putative phosphatase active site
cysteine
at position 231 was substituted for a serine displayed full restoration of both cell proliferation and Akt activation. In conclusion, C1-TEN appears to be a novel intracellular phosphatase that negatively regulates the Akt/
PKB
signaling cascade, and is similar to its relative PTEN in this respect. However, the particular domain organization of C1-TEN may enable it to regulate RTK and other signaling complexes that are linked to Akt/
PKB
signaling in a unique manner.
...
PMID:C1-TEN is a negative regulator of the Akt/PKB signal transduction pathway and inhibits cell survival, proliferation, and migration. 1581 39
N-acetyl-
cysteine
(NAC) has been reported to have anticancer properties such as counteractions against mutagens and prevention of tumor progression by scavenging reactive oxygen species (ROS). However, here we report that NAC can enhance the anchorage-independent growth of cells transformed by activated
ABL
tyrosine kinases or Ras. This effect was not dependent on loss of
focal adhesion kinase
activation. NAC rescued cell growth that was suppressed by heat shock protein (Hsp) 90 inhibitors possibly by chemical modification of their quinone moiety. NAC rendered Rat1/BCR-
ABL
cells resistance to a Ras inhibitor manumycin in soft agar colony formation. In the absence of Hsp90 inhibitors, NAC stimulated the activation of MAP kinase in BCR-
ABL
-transformed but not in the parental Rat1 cells. We propose that NAC should be used carefully in cancer treatment.
...
PMID:N-acetyl-cysteine enhances growth in BCR-ABL-transformed cells. 1581 23
We used two-dimensional difference gel electrophoresis to determine early changes in the stress-response pathways that precede focal adhesion disorganization linked to the onset of apoptosis of renal epithelial cells. Treatment of LLC-PK1 cells with the model nephrotoxicant 1,2-(dichlorovinyl)-
L-cysteine
(DCVC) resulted in a >1.5-fold up- and down-regulation of 14 and 9 proteins, respectively, preceding the onset of apoptosis. Proteins included those involved in metabolism, i.e. aconitase and pyruvate dehydrogenase, and those related to stress responses and cytoskeletal reorganization, i.e. cofilin, Hsp27, and alpha-b-crystallin. The most prominent changes were found for Hsp27, which was related to a pI shift in association with an altered phosphorylation status of serine residue 82. Although both p38 and JNK were activated by DCVC, only inhibition of p38 with SB203580 reduced Hsp27 phosphorylation, which was associated with accelerated reorganization of focal adhesions, cell detachment, and apoptosis. In contrast, inhibition of JNK with SP600125 maintained cell adhesion as well as protection against apoptosis. Active JNK co-localized at focal adhesions after DCVC treatment in a
FAK
-dependent manner. Inhibition of active JNK localization at focal adhesions did not prevent DCVC-induced phosphorylation of Hsp27. Overexpression of a phosphorylation-defective mutant Hsp27 acted as a dominant negative and accelerated the DCVC-induced changes in the focal adhesions as well as the onset of apoptosis. Our data fit a model whereby early p38 activation results in a rapid phosphorylation of Hsp27, a requirement for proper maintenance of cell adhesion, thus suppressing renal epithelial cell apoptosis.
...
PMID:Heat shock protein 27 is the major differentially phosphorylated protein involved in renal epithelial cellular stress response and controls focal adhesion organization and apoptosis. 1594 57
Protein Kinase Balpha(PKBalpha, or Akt1) is believed to play a crucial role in programmed cell death, cancer progression and the insulin-signaling cascade. The protein is activated by phosphorylation at multiple sites and subsequently phosphorylates and activates eNOS.
Free cysteine
residues of the protein may capture reactive, endogenously produced nitric oxide (NO) as S-nitrosothiols. Site-specific detection of S-nitrosylated
cysteine
residues, usually at low stoichiometry, has been a major challenge in proteomic research largely due to the lack of mass marker for S-nitrosothiols that are very labile under physiologic conditions. In this report we describe a sensitive and specific MS method for detection of S-nitrosothiols in
PKB
alpha/Akt1 in rat soleus muscle.
PKB
alpha/Akt1 was isolated by immunoprecipitation and 2D-gel electrophoresis, subjected to in-gel tryptic digestion, and cysteinyl nitrosothiols were reacted with iodoacetic acids [2-C(12)/C(13) = 50/50] under ascorbate reduction conditions. This resulted in the production of relatively stable carboxymethylcysteine (CMC) immonium ions (m/z 134.019 and m/z 135.019) within a narrow argon collision energy (CE = 30 +/- 5 V) in the high MS noise region. In addition, free and disulfide-linked
cysteine
residues were converted to carboxyamidomethylcysteines (CAM). Tryptic S-nitrosylated parent ion was detected with a mass accuracy of 50 mDa for the two CMC immonium ions at the triggered elution time during capillary liquid chromatography (LC) separation. A peptide containing Cys(296) was discriminated from four co-eluting tryptic peptides under lock mass conditions (m/z 785.8426). S-nitrosothiol in the tryptic peptide, ITDFGLBKEGIK (B: CAM, [M + 2H](2+) = 690.86, Found: 690.83), is believed to be present at a very low level, since the threshold for the CMC immonium trigger ions was set at 3 counts/s in the MS survey. The high levels of NO that are produced under stress conditions may result in increased S-nitrosylation of Cys(296) which blocks disulfide bond formation between Cys(296) and Cys(310) and suppresses the biological effects of
PKB
alpha/Akt1. With the procedures developed here, this process can be studied under physiological and pathological conditions.
...
PMID:Site-specific detection of S-nitrosylated PKB alpha/Akt1 from rat soleus muscle using CapLC-Q-TOF(micro) mass spectrometry. 1604 29
Among the 10 human Toll-like receptors (TLRs), TLR2 appears to be unique in its requirement for cooperation with other TLRs, namely TLR1 and TLR6, to mediate cell signaling. Through reconstitution experiments, we have defined more precisely the function of these human TLRs. Human colonic epithelial cells cotransfected with TLR1 and -2 preferentially respond to a synthetic tripalmitoylated bacterial lipopeptide analogue (Pam(3)
CSK
(4)). However, examination of a wide variety of lipopeptide derivatives indicates that recognition by human TLR1 and -2 does not strictly correlate with the number or position of the acyl chains on the modified
cysteine
residue. Conversely, human TLR2 and -6 exclusively respond to lipopeptides possessing a diacylglycerol group. Most surprisingly, we have found that an R stereoisomer of diacylated macrophage-activating lipopeptide 2 (MALP-2) exclusively activates epithelial cells through TLR6 and -2 but not through TLR1 and -2. These results suggest that the chirality of the central carbon of the diacylglycerol group of these agonists is a structural determinant for human TLR recognition. Examination of chimeric receptors, generated by domain exchange between TLR1 and -6, has revealed that leucine-rich repeats 9-12 of the extracellular domain enable these receptors to discriminate between structurally similar lipopeptides. However, additional chimeric constructs reveal that this region alone is not sufficient to generate receptors that can functionally cooperate with TLR2. Our results support the idea that TLR1 and TLR6 diverged during evolution to differentially recognize natural lipoprotein structures and that this function has been conserved with respect to the human receptors.
...
PMID:Domain exchange between human toll-like receptors 1 and 6 reveals a region required for lipopeptide discrimination. 1612 84
Extracellular matrix proteins and cell adhesion receptors (integrins) play essential roles in the regulation of cell adhesion and migration. Interactions of integrins with the extracellular matrix proteins lead to phosphorylation of several intracellular proteins such as
focal adhesion kinase
, activating different signaling pathways responsible for the regulation of a variety of cell functions, including cytoskeleton mobilization. Once leukocytes are guided to sites of infection, inflammation, or antigen presentation, integrins can participate in the initiation, maintenance, or termination of the immune and inflammatory responses. The modulation of neutrophil activation through integrin-mediated pathways is important in the homeostatic control of the resolution of inflammatory states. In addition, during recirculation, T lymphocyte movement through distinct microenvironments is mediated by integrins, which are critical for cell cycle, differentiation and gene expression. Disintegrins are a family of low-molecular weight,
cysteine
-rich peptides first identified in snake venom, usually containing an RGD (Arg-Gly-Asp) motif, which confers the ability to selectively bind to integrins, inhibiting integrin-related functions in different cell systems. In this review we show that, depending on the cell type and the microenvironment, disintegrins are able to antagonize the effects of integrins or to act agonistically by activating integrin-mediated signaling. Disintegrins have proven useful as tools to improve the understanding of the molecular events regulated by integrin signaling in leukocytes and prototypes in order to design therapies able to interfere with integrin-mediated effects.
...
PMID:Disintegrins: integrin selective ligands which activate integrin-coupled signaling and modulate leukocyte functions. 1617 44
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