Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Integrins are adhesion receptors that transmit signals bidirectionally across the plasma membrane. In our previous report we have shown that the squamous lung cancer cell line, Calu-1, binds to collagen type IV (Coll IV) through beta1-integrin and results in phosphorylation of focal adhesion kinase (FAK) (Ann Thorac Surg 2004; 78:450-457). Considering the critical role of FAK in cell migration, proliferation, and survival, here we investigated potential mechanisms of its activation and regulation in Calu-1 cells. We observed the phosphorylation of Tyr397 of FAK (the autophosphorylation site of FAK) and paxillin, the immediate downstream substrate of FAK following the adhesion of Calu-1 cells to Coll IV. FAK remains phosphorylated during proliferation either on Coll IV or on uncoated plates for 72 h, as determined by peroxivanadate treatment. Exposure of Calu-1 cells with 60 microM genistein, reduces FAK phosphorylation (7.6 fold) and cell proliferation. Extracellular signal regulated kinases (ERKs) were also phosphorylated after Coll IV attachment. Disruption of Calu-1 cell cytoskeleton integrity by 1-5 muM Cytochalasin D resulted in the inhibition of cell adhesion (50% to 75%, p<0.19 - 6.6 x 10(7)) and ERKs phosphorylation (2 fold) without any effect on FAK phosphorylation. Protein Kinase C inhibitor, Calphostin C at 100 and 250 nM concentrations did not block Coll IV induced FAK phosphorylation but activated the ERKs in a dose dependent manner. beta1-integrin is essential for Coll IV induced FAK activation, but it is not physically associated with FAK as determined by immunodetection assay. Collectively, this report defines the existence of multiple and potentially parallel Coll IV/beta1-integrin mediated signaling events in Calu-1 cells, which involve FAK, ERKs, and PKC.
 ...
PMID:Activation of focal adhesion kinase in human lung cancer cells involves multiple and potentially parallel signaling events. 1596 58

Cellular cytoskeletal remodeling reflects alterations in local biochemical and mechanical changes in terms of stress that manifests relocation of signaling molecules within and across the cell. Although stretching due to load and chemical changes by high homocysteine (HHcy) causes cytoskeletal re-arrangement, the synergism between stretch and HHcy is unclear. We investigated the contribution of HHcy in cyclic stretch-induced focal adhesion (FA) protein redistribution leading to cytoskeletal re-arrangement in mouse aortic endothelial cells (MAEC). MAEC were subjected to cyclic stretch (CS) and HHcy alone or in combination. The redistribution of FA protein, and small GTPases were determined by Confocal microscopy and Western blot techniques in membrane and cytosolic compartments. We found that each treatment induces focal adhesion kinase (FAK) phosphorylation and cytoskeletal actin polymerization. In addition, CS activates and membrane translocates small GTPases RhoA with minimal effect on Rac1, whereas HHcy alone is ineffective in both GTPases translocation. However, the combined effect of CS and HHcy activates and membrane translocates both GTPases. Free radical scavenger NAC (N-Acetyl-Cysteine) inhibits CS and HHcy-mediated FAK phosphorylation and actin stress fiber formation. Interestingly, CS also activates and membrane translocates another FA protein, paxillin in HHcy condition. Cytochalasin D, an actin polymerization blocker and PI3-kinase inhibitor Wortmannin inhibited FAK phosphorylation and membrane translocation of paxillin suggesting the involvement of PI3K pathway. Together our results suggest that CS- and HHcy-induced oxidative stress synergistically contribute to small GTPase membrane translocation and focal adhesion protein redistribution leading to endothelial remodeling.
 ...
PMID:Homocysteine-induced biochemical stress predisposes to cytoskeletal remodeling in stretched endothelial cells. 1752 26

Chronic exposure to solar ultraviolet radiation (UV) induces photoaging, and ultimately photocarcinogenesis. Senescent human skin fibroblasts (HSFs) in UVB stress-induced premature senescence (UVB-SIPS) share a similar extracellular matrix (ECM) phenotype with other types of senescent fibroblast. ECM from senescent fibroblasts induced by a variety of stresses has been shown to promote preneoplastic and neoplastic epithelial cell growth, a potential mechanism in carcinogenesis. We undertook this study to explore whether the extracellular matrices from UVB-induced senescent fibroblasts have any effect on the proliferation of HaCaT cells. The results showed that ECM secreted from HSFs in UVB-SIPS has 13.15 and 29.27% more stimulatory effect on proliferation than ECM secreted from presenescent HSFs and non-ECM, respectively. ECM from fibroblasts in UVB-SIPS activates FAK, ERK, and AKT in HaCaT cells. ERK and PI3K/AKT inhibitors inhibit ECM-induced ERK, AKT activation and cell proliferation. Cytochalasin D, a destructive agent of the cytoskeleton, inhibits ECM-induced FAK activation and cell proliferation in HaCaT cells. Collectively, we conclude that ECM secreted from HSFs in UVB-SIPS promotes cell proliferation via ERK and PI3K/AKT pathways and modulation of FAK and cytoskeletal proteins in HaCaT cells. Pharmacological manipulation of those signaling components may lead to the prevention and treatment of skin cancer induced by chronic solar exposure.
 ...
PMID:Extracellular matrix secreted by senescent fibroblasts induced by UVB promotes cell proliferation in HaCaT cells through PI3K/AKT and ERK signaling pathways. 1850 72

While Src plays crucial roles in shear stress-induced cellular processes, little is known on the spatiotemporal pattern of high shear stress (HSS)-induced Src activation. HSS (65 dyn/cm(2)) was applied on bovine aortic endothelial cells to visualize the dynamic Src activation at subcellular levels utilizing a membrane-targeted Src biosensor (Kras-Src) based on fluorescence resonance energy transfer (FRET). A polarized Src activation was observed with higher activity at the side facing the flow, which was enhanced by a cytochalasin D-mediated disruption of actin filaments but inhibited by a benzyl alcohol-mediated enhancement of membrane fluidity. Further experiments revealed that HSS decreased RhoA activity, with a constitutively active RhoA mutant inhibiting while a negative RhoA mutant enhancing the HSS-induced Src polarity. Cytochalasin D can restore the polarity in cells expressing the active RhoA mutant. Further results indicate that HSS stimulates FAK activation with a spatial polarity similar to Src. The inhibition of Src by PP1, as well as the perturbation of RhoA activity and membrane fluidity, can block this HSS-induced FAK polarity. These results indicate that the HSS-induced Src and subsequently FAK polarity depends on the coordination between intracellular tension distribution regulated by RhoA, its related actin structures and the plasma membrane fluidity.
 ...
PMID:RhoA and membrane fluidity mediates the spatially polarized Src/FAK activation in response to shear stress. 2538 6


<< Previous 1 2 3