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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 mammary gland is a highly organized tissue, containing ductal structures, secretory alveolar units, and a supporting stroma. The organization of the epithelial cells within the tissue depends upon cell-cell adhesion as well as cell interactions with the extracellular matrix that underlies the epithelial units and makes up most of the organization of the stroma. Adhesion to the extracellular matrix is mediated by a class of heterodimeric transmembrane receptors called integrins, which cluster at focal adhesions. Integrins link the matrix with an intracellular structural scaffold, the cytoskeleton, as well as with signaling enzymes that direct cell survival, proliferation, differentiation, and migration. Two key enzymes that are recruited to sites of integrin clustering are
focal adhesion kinase
and
integrin-linked kinase
. Both enzymes are involved with communication downstream of integrins and have key roles in regulating cell behavior. This review will focus on what is known about
focal adhesion kinase
and
integrin-linked kinase
signaling and will discuss current evidence about their role in mammary gland biology and neoplasia.
...
PMID:Integrin signaling and mammary cell function. 1498 36
Rho GTPases, Cdc42 and Rac1, play pivotal roles in cell migration by efficiently integrating cell-substrate adhesion and actin polymerization. Although it has been suggested that integrins stimulate these Rho GTPases via some of integrin binding proteins such as
focal adhesion kinase
(
FAK
) and paxillin, the precise molecular mechanism is largely unknown. In this study, we showed that the over-expression of RP1 corresponding to the first CH domain (CH1) of affixin, an
integrin-linked kinase
(
ILK
)-binding protein, induced a significant actin reorganization in MDCK cells by activating Cdc42/Rac1. Affixin full length and RP1 co-immunoprecipitated with alphaPIX, a Cdc42/Rac1-specific guanine nucleotide exchanging factor (GEF), and they co-localized at the tips of lamellipodia in motile cells. The involvement of alphaPIX in the RP1-induced Cdc42 activation was demonstrated by the significant dominant negative effect of a point mutant of alphaPIX, alphaPIX (L383R, L384S), lacking GEF activity. Our data strongly support that
ILK
and affixin provide a novel signalling pathway that links integrin signalling to Cdc42/Rac1 activation.
...
PMID:The first CH domain of affixin activates Cdc42 and Rac1 through alphaPIX, a Cdc42/Rac1-specific guanine nucleotide exchanging factor. 1500 7
The quinazoline family of alpha1-blockers (prazosin, doxazosin, and terazosin) induce apoptosis of prostate cells through an alpha1-adrenoceptor-independent mechanism. The objective of this study was to gain insight into the non-adrenergic, apoptotic mechanism of action of doxazosin in the prostate and the induction of anoikis by doxazosin. Primary cultures of benign prostate stromal and epithelial cells and the LNCaP (androgen sensitive) and PC-3 (androgen insensitive) prostate carcinoma cell lines were treated with doxazosin (0-50 microM). The effects of doxazosin on cell morphology, caspase-3 activity, and the expression levels of
focal adhesion kinase
(
FAK
) and
integrin-linked kinase
(
ILK
) were examined. Doxazosin induced changes in morphology consistent with anoikis in both benign and cancerous prostatic cells and increased caspase-3 activity. The effects were similar comparing benign cells (which express alpha1-adrenoceptors) and cancer cells (which do not express alpha1-adrenoceptors), but were more robust in benign cells. Norepinephrine had no effect on doxazosin-induced cell morphology or caspase-3 activity. Treatment of PC-3 cells with doxazosin significantly reduced the protein levels of
FAK
but did not significantly affect the levels of
ILK
. These findings suggest that doxazosin induces apoptosis and anoikis of prostate cancer cells by a mechanism of action that is alpha1-adrenoceptor independent. The apoptosis of cancer cells induced by doxazosin counteracts cell proliferation and may have the potential of retarding or reversing prostate cancer cell growth.
...
PMID:Induction of anoikis by doxazosin in prostate cancer cells is associated with activation of caspase-3 and a reduction of focal adhesion kinase. 1522 Dec 43
We analysed breast tumors and breast cancer cell lines for the expression of beta-parvin (ParvB), an adaptor protein that binds to the
integrin-linked kinase
(
ILK
). Quantitative RT-PCR indicated that ParvB mRNA was downregulated, by at least 60%, in four of nine breast tumors, relative to patient-matched normal mammary gland tissue. We also found that ParvB protein levels were reduced by > or =90% in five of seven advanced tumors, relative to matched normal breast tissue. Conversely,
ILK
protein and kinase activity levels were elevated in these tumors, suggesting that downregulation of ParvB stimulates
ILK
signaling. Western blot analyses indicated very low levels of ParvB protein in MDA-MB-231 and MCF7 breast cancer cells, facilitating functional studies of the effects of ParvB on
ILK
signaling. Expression of ParvB in MDA-MB-231 and MCF7 cells increased cell adhesion to collagen. ParvB inhibited
ILK
kinase activity, anchorage-independent cell growth and in vitro matrigel invasion by MDA-MB-231 cells. EGF-induced phosphorylation of two
ILK
targets,
PKB
(Ser473) and glycogen synthase kinase 3beta (Ser9), was also inhibited by ParvB. These results indicated that ParvB inhibits
ILK
signaling downstream of receptor tyrosine kinases. Our results suggest that loss of ParvB expression is a novel mechanism for upregulating
ILK
activity in tumors.
...
PMID:Beta-parvin inhibits integrin-linked kinase signaling and is downregulated in breast cancer. 1546 40
The
integrin-linked kinase
(
ILK
) is a multidomain focal adhesion protein implicated in signal transmission from integrin and growth factor receptors. We have determined that
ILK
regulates U2OS osteosarcoma cell spreading and motility in a manner requiring both kinase activity and localization. Overexpression of wild-type (WT)
ILK
resulted in suppression of cell spreading, polarization, and motility to fibronectin. Cell lines overexpressing kinase-dead (S343A) or paxillin binding site mutant
ILK
proteins display inhibited haptotaxis to fibronectin. Conversely, spreading and motility was potentiated in cells expressing the "dominant negative," non-targeting, kinase-deficient E359K
ILK
protein. Suppression of cell spreading and motility of WT
ILK
U2OS cells could be rescued by treatment with the Rho-associated kinase (ROCK) inhibitor Y-27632 or introduction of dominant negative ROCK or RhoA, suggesting these cells have increased RhoA signaling. Activation of
focal adhesion kinase
(
FAK
), a negative regulator of RhoA, was reduced in WT
ILK
cells, whereas overexpression of
FAK
rescued the observed defects in spreading and cell polarity. Thus,
ILK
-dependent effects on ROCK and/or RhoA signaling may be mediated through
FAK
.
...
PMID:The integrin-linked kinase regulates cell morphology and motility in a rho-associated kinase-dependent manner. 1548 19
PINCH1 is composed of 5 LIM domains, binds
integrin-linked kinase
(
ILK
) and locates to integrin-mediated adhesion sites. In order to investigate PINCH1 function we generated mice and embryonic stem (ES) cell-derived embryoid bodies (EBs) lacking the PINCH1 gene. Similar to mice lacking beta1 integrin or Ilk, loss of PINCH1 arrested development at the peri-implantation stage. In contrast to beta1 integrin or Ilk mutants, however, disruption of the PINCH1 gene produced implantation chambers with visible cell clumps even at embryonic day 9.5. In order to define the phenotype leading to the peri-implantation lethality we made PINCH1-null EBs and found similar but also additional defects not observed in beta1 integrin or Ilk mutant EBs. The similarities included abnormal epiblast polarity, impaired cavitation and detachment of endoderm and epiblast from basement membranes. Additional defects, which were not observed in beta1 integrin- or
ILK
-deficient mice or EBs, included abnormal cell-cell adhesion of endoderm and epiblast as well as the presence of apoptotic cells in the endodermal cell layer. Although
ILK
and PINCH1 were shown to be involved in the phosphorylation of serine-473 of
PKB
/Akt, immunostaining with specific antibodies revealed no apparent alteration of
PKB
/Akt phosphorylation in PINCH1-deficient EBs. Altogether these data demonstrate an important role of PINCH1 for integrin function, actin organization, cell-cell adhesion and endodermal cell survival during the implanting of mouse embryos.
...
PMID:PINCH1 regulates cell-matrix and cell-cell adhesions, cell polarity and cell survival during the peri-implantation stage. 1597 50
We have found previously that human plasma-membrane-associated sialidase (NEU3), a key glycosidase for ganglioside degradation, was markedly up-regulated in human colon cancers, with an involvement in suppression of apoptosis. To elucidate the molecular mechanisms underlying increased NEU3 expression, in the present study we investigated its role in cell adhesion of human colon cancer cells. DLD-1 cells transfected with NEU3 exhibited increased adhesion to laminins and consequent cell proliferation, but decreased cell adhesion to fibronectin and collagens I and IV, compared with control cells. When triggered by laminins, NEU3 clearly stimulated phosphorylation of
FAK
(
focal adhesion kinase
) and ERK (extracellular-signal-regulated kinase), whereas there was no activation on fibronectin. NEU3 markedly enhanced tyrosine phosphorylation of integrin beta4 with recruitment of Shc and Grb-2 only on laminin-5, and NEU3 was co-immunoprecipitated by an anti-(integrin beta4) antibody, suggesting that association of NEU3 with integrin beta4 might facilitate promotion of the integrin-derived signalling on laminin-5. In addition, the promotion of phosphorylation of integrin beta1 and ILK (
integrin-linked kinase
) was also observed on laminins. G(M3) depletion as the result of NEU3 overexpression, assessed by TLC, appeared to be one of the causes of the increased adhesion on laminins and, in contrast, of the decreased adhesion on fibronectin - NEU3 probably having bimodal effects. These results indicate that NEU3 differentially regulates cell proliferation through integrin-mediated signalling depending on the extracellular matrix and, on laminins, NEU3 did indeed activate molecules often up-regulated in carcinogenesis, which may cause an acceleration of the malignant phenotype in cancer cells.
...
PMID:Plasma-membrane-associated sialidase (NEU3) differentially regulates integrin-mediated cell proliferation through laminin- and fibronectin-derived signalling. 1624 5
The ovarian surface epithelium (OSE) is the precursor of common epithelial ovarian carcinomas. In the present study, we examined the molecular mechanisms and possible physiological basis for the propensity of OSE cells to undergo epithelio-mesenchymal transition (EMT) in response to environmental influences. We hypothesized that EMT may be a homeostatic mechanism that permits displaced OSE to assume a stromal phenotype within the ovarian cortex. We report that EGF in conjunction with hydrocortisone is the EMT-inducing factor of OSE as shown by changes to a fibroblast-like morphology and growth pattern. EGF increased cell motility, enhanced the activities of secreted pro-matrix metalloproteinase (MMP)-2 and -9, and enhanced expression and activation of Erk and
integrin-linked kinase
(
ILK
). Increased
ILK
expression correlated with the activation of
PKB
/Akt, the phosphorylation of GSK-3beta, and the increased expression of cyclin E and cdk2 kinase. EGF withdrawal resulted in a more epithelial morphology and reversal of the EGF-induced activation of signaling pathways and pro-MMP activity. In contrast, treatment of EGF-treated cells with specific inhibitors of phosphatidylinositol 3-kinase, Mek, or
ILK
inhibited the inhibitor-specific pathways. The inhibitors caused suppression of EGF-induced migration and pro-MMP-2/-9 activities but did not lead to any change in EGF-induced mesenchymal morphology.
ILK
small interfering RNA inhibited Akt phosphorylation and reduced pro-MMP-2/-9 activities but had no effect on Erk activation or cell morphology. These results indicate that the EGF-induced morphological and functional changes in OSE cells are controlled by distinct signaling mechanisms working in concert. EMT of OSE cells displaced by ovulation likely permits their survival and integration with a fibroblast-like identity within the stroma. Failure to do so may lead to the formation of epithelium-derived inclusion cysts, which are known preferential sites of malignant transformation.
...
PMID:Molecular pathways regulating EGF-induced epithelio-mesenchymal transition in human ovarian surface epithelium. 1639 28
Histidine-rich glycoprotein (HRGP) is an abundant heparin-binding plasma protein that efficiently arrests growth and vascularization of mouse tumor models. We have shown that the antiangiogenic effect of HRGP is dependent on its histidine/proline-rich domain, which needs to be released from the mother protein to exert its effects. Here we identify a 35-amino-acid peptide, HRGP330, derived from the histidine/proline-rich domain as endowed with antiangiogenic properties in vitro and in vivo. The mechanism of action of HRGP330 involves subversion of focal adhesion function by disruption of
integrin-linked kinase
(
ILK
) and
focal adhesion kinase
(
FAK
) functions, inhibition of vascular endothelial growth factor (VEGF)-induced tyrosine phosphorylation of the
FAK
substrate alpha-actinin, and, as a consequence, an arrest in endothelial cell motility. The disturbed focal adhesion function is reflected in the ability of HRGP as well as of HRGP330 to prevent endothelial cell adhesion to vitronectin in a manner involving alpha(v)beta3 integrin. In conclusion, HRGP330, which we define as the minimal antiangiogenic domain of HRGP, exerts its effects through signal transduction targeting focal adhesions, thereby interrupting VEGF-induced endothelial cell motility.
...
PMID:Minimal active domain and mechanism of action of the angiogenesis inhibitor histidine-rich glycoprotein. 1648 9
A requirement for integrin-mediated adhesion in cardiac physiology is revealed through targeted deletion of integrin-associated genes in the murine heart. Here we show that targeted ablation of the
integrin-linked kinase
(
ILK
) expression results in spontaneous cardiomyopathy and heart failure by 6 wk of age. Deletion of
ILK
results in disaggregation of cardiomyocytes, associated with disruption of adhesion signaling through the beta1-integrin/
FAK
(
focal adhesion kinase
) complex. Importantly, the loss of
ILK
is accompanied by a reduction in cardiac Akt phosphorylation, which normally provides a protective response against stress. Together, these results suggest that
ILK
plays a central role in protecting the mammalian heart against cardiomyopathy and failure.
...
PMID:Targeted ablation of ILK from the murine heart results in dilated cardiomyopathy and spontaneous heart failure. 1695 Dec 52
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