Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Normal endothelial and epithelial cells undergo apoptosis when cell adhesion and spreading are prevented, implying a requirement for antiapoptotic signals from the extracellular matrix for cell survival. We investigated some of the molecular changes occurring in focal adhesions during growth factor deprivation-induced apoptosis in confluent monolayers of human umbilical vein endothelial cells. Among the first morphologic changes after initiation of the apoptotic process are membrane blebbing, loss of focal adhesion sites, and retraction from the matrix followed by detachment. We observe a specific proteolytic cleavage of focal adhesion kinase (pp125FAK), an important component of the focal adhesion complex, and identify pp125FAK as a novel substrate for caspase-3 and caspase-3-like apoptotic caspases. The initial cleavage precedes detachment, and coincides with loss of pp125FAK and paxillin from focal adhesion sites and their redistribution into the characteristic membrane blebs of apoptotically dying cells. Cleavage of pp125FAK differentially affects its association with signaling and cytoskeletal components of the focal adhesion complex; binding of paxillin, but not pp130(Cas) (Cas, Crk-associated substrate) and vinculin, to the COOH terminally truncated pp125FAK is abolished. Therefore, caspase-mediated cleavage of pp125FAK may be participating in the disassembly of the focal adhesion complex and actively interrupting survival signals from the extracellular matrix, thus propagating the cell death program.
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PMID:Caspase-mediated cleavage of focal adhesion kinase pp125FAK and disassembly of focal adhesions in human endothelial cell apoptosis. 946 8

The relationship between focal adhesion protein (FAK) activity and loss of cell-matrix contact during apoptosis is not entirely clear nor has the role of FAK in chemically induced apoptosis been studied. We investigated the status of FAK phosphorylation and cleavage in renal epithelial cells during apoptosis caused by the nephrotoxicant dichlorovinylcysteine (DCVC). DCVC treatment caused a loss of cell-matrix contact which was preceded by a dissociation of FAK from the focal adhesions and tyrosine dephosphorylation of FAK. Paxillin was also dephosphorylated at tyrosine. DCVC treatment activated caspase-3 which was associated with cleavage of FAK. However, FAK cleavage occurred after cells had already lost focal adhesions indicating that cleavage of FAK by caspases is not responsible for loss of FAK from focal adhesions. Accordingly, although inhibition of caspase activity with zVAD-fmk blocked activation of caspase-3, FAK cleavage, and apoptosis, it neither affected dephosphorylation nor translocation of FAK or paxillin. However, zVAD-fmk completely blocked the cell detachment caused by DCVC treatment. Orthovanadate prevented DCVC-induced tyrosine dephosphorylation of both FAK and paxillin; however, it did not inhibit DCVC-induced apoptosis and actually potentiated focal adhesion disorganization and cell detachment. Thus, FAK dephosphorylation and loss of focal adhesions are not due to caspase activation; however, caspases are required for FAK proteolysis and cell detachment.
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PMID:Dephosphorylation of focal adhesion kinase (FAK) and loss of focal contacts precede caspase-mediated cleavage of FAK during apoptosis in renal epithelial cells. 1022 94

Apoptosis causes characteristic morphological changes in cells, including membrane blebbing, cell detachment from the extracellular matrix, and loss of cell-cell contacts. We investigated the changes in focal adhesion proteins during etoposide-induced apoptosis in Rat-1 cells and found that during apoptosis, p130cas (Crk-associated substrate [Cas]) is cleaved by caspase-3. Sequence analysis showed that Cas contains 10 DXXD consensus sites preferred by caspase-3. We identified two of these sites (DVPD(416)G and DSPD(748)G) in vitro, and point mutations substituting the Asp of DVPD(416)G and DSPD(748)G with Glu blocked caspase-3-mediated cleavage. Cleavage at DVPD(416)G generated a 74-kDa fragment, which was in turn cleaved at DSPD(748)G, yielding 47- and 31-kDa fragments. Immunofluorescence microscopy revealed well-developed focal adhesion sites in control cells that dramatically declined in number in etoposide-treated cells. Cas cleavage correlated temporally with the onset of apoptosis and coincided with the loss of p125FAK (focal adhesion kinase [FAK]) from focal adhesion sites and the attenuation of Cas-paxillin interactions. Considering that Cas associates with FAK, paxillin, and other molecules involved in the integrin signaling pathway, these results suggest that caspase-mediated cleavage of Cas contributes to the disassembly of focal adhesion complexes and interrupts survival signals from the extracellular matrix.
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PMID:Caspase-mediated cleavage of p130cas in etoposide-induced apoptotic Rat-1 cells. 1071 10

Decreased phosphorylation of focal adhesion kinase and paxillin is associated with loss of focal adhesions and stress fibers and precedes the onset of apoptosis (van de Water, B., Nagelkerke, J. F., and Stevens, J. L. (1999) J. Biol. Chem. 274, 13328-13337). The cortical actin cytoskeletal network is also lost during apoptosis, yet little is known about the temporal relationship between altered phosphorylation of proteins that are critical in the regulation of this network and their potential cleavage by caspases during apoptosis. Adducins are central in the cortical actin network organization. Cisplatin caused apoptosis of renal proximal tubular epithelial cells, which was associated with the cleavage of alpha-adducin into a 74-kDa fragment; this was blocked by a general caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk). Hemagglutinin-tagged human alpha-adducin was cleaved into a similar 74-kDa fragment by caspase-3 in vitro but not by caspase-6 or -7. Asp-Arg-Val-Asp(29)-Glu, Asp-Ile-Val-Asp(208)-Arg, and Asp-Asp-Ser-Asp(633)-Ala were identified as the principal caspase-3 cleavage sites; Asp-Asp-Ser-Asp(633)-Ala was key in the formation of the 74-kDa fragment. Cisplatin also caused an increased phosphorylation of alpha-adducin and gamma-adducin in the MARCKS domain that preceded alpha-adducin cleavage and was associated with loss of adducins from adherens junctions; this was not affected by z-VAD-fmk. In conclusion, the data support a model in which increased phosphorylation of alpha-adducin due to cisplatin leads to dissociation from the cytoskeleton, a situation rendered irreversible by caspase-3-mediated cleavage of alpha-adducin at Asp-Asp-Ser-Asp(633)-Ala.
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PMID:Cleavage of the actin-capping protein alpha -adducin at Asp-Asp-Ser-Asp633-Ala by caspase-3 is preceded by its phosphorylation on serine 726 in cisplatin-induced apoptosis of renal epithelial cells. 1082 23

Decreased phosphorylation of focal adhesion kinase (FAK) is associated with loss of focal adhesions and actin stress fibers and precedes the onset of apoptosis in renal epithelial cells caused by nephrotoxicants (Van de Water, B., Nagelkerke, J. F., and Stevens, J. L. (1999) J. Biol. Chem. 274, 13328-13337). The role of FAK in the control of apoptosis caused by nephrotoxicants was further investigated in LLC-PK1 cells that were stably transfected with either green fluorescent protein (GFP)-FAK or dominant negative acting deletion mutants of FAK, GFP-FAT, and GFP-FRNK. GFP-FAT and GFP-FRNK delayed the formation of focal adhesions and prevented the localization of endogenous (phosphorylated) FAK at these sites. GFP-FAT and GFP-FRNK overexpression potentiated the onset of apoptosis caused by the nephrotoxicant dichlorovinyl-cysteine. This was associated with an increased activation of caspase-3. GFP-FAT also potentiated apoptosis caused by doxorubicin but not cisplatin. The potentiation of apoptosis by GFP-FAT was related to an almost complete dephosphorylation of FAK; this did not occur in cells overexpressing only GFP. This dephosphorylation was associated with a pronounced loss of focal adhesion organization in GFP-FAT cells, in association with loss of tyrosine phosphorylation of paxillin. In conclusion, the data indicate an important role of cell-matrix signaling in the control of chemically induced apoptosis; loss of FAK activity caused by toxic chemicals results in perturbations of focal adhesion organization with a subsequent inactivation of associated (signaling) molecules and loss of survival signaling.
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PMID:Suppression of chemically induced apoptosis but not necrosis of renal proximal tubular epithelial (LLC-PK1) cells by focal adhesion kinase (FAK). Role of FAK in maintaining focal adhesion organization after acute renal cell injury. 1144 17

Immunofluorescence microscopy revealed the rearrangement and gradual dissociation of paxillin from focal adhesion sites during apoptosis. In vitro, cleavage of paxillin by caspase-3 generated a 42-kDa fragment, among other products, while cleavage by calpain generated a different set of fragments. In Rat-1 cells, cleavage of paxillin by caspase-3 was suppressed by zVAD-fmk or zDEVD-cmk, making caspase-3 a likely executioner during etoposide-induced apoptosis. In contrast, the cleavage of paxillin and p130cas in apoptotic L929 cells was blocked by calpain-specific inhibitors, which also reduced the death rate by 23 to 44%. Therefore, The disassembly and degradation of p130cas and paxillin during apoptosis may controlled by both caspases and calpains, depending upon their cellular contexts. Our findings also suggest that focal adhesion proteins paxillin and p130cas take part in integrin-mediated signaling for cell survival, and that their cleavage by caspase and/or calpain may not only disrupt focal adhesion complexes, but may also impede cell survival signaling.
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PMID:Degradation of focal adhesion proteins paxillin and p130cas by caspases or calpains in apoptotic rat-1 and L929 cells. 1151 Nov 2

We have cloned the complete cDNA from mouse paxillin, a 68-kDa adapter protein found in focal adhesions. We found that paxillin was degraded by caspases in Ba/F3 cell apoptosis induced by withdrawal of interleukin-3 (IL-3), a survival factor for this cell, and by ionizing radiation. Also, paxillin was degraded in vitro by incubation with recombinant caspase-3. Western blot analyses of degradation products of overexpressed green fluorescence protein-tagged paxillin and site-specific mutants demonstrated that Asp-102 and Asp-301 were early caspase cleavage sites, and Asp-5, Asp-146, Asp-165, and Asp-222 were late cleavage sites. Overexpression of paxillin delayed apoptosis of Ba/F3 after IL-3 withdrawal. Furthermore, this anti-apoptotic effect of paxillin was augmented by a triple mutation in aspartic acids at caspase cleavage sites. These results suggest that paxillin plays a critical role in cell survival signaling and that the cleavage of paxillin by caspases might be an important event for focal adhesion disassembly during cell apoptosis, contributing to detachment, rounding, and death.
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PMID:Linkage of caspase-mediated degradation of paxillin to apoptosis in Ba/F3 murine pro-B lymphocytes. 1182 2

Ochratoxin A (OTA), a metabolite produced by strains of Aspergillus and Penicillium, has nephritogenic, carcinogenic, and teratogenic activity in animals and humans. Nanomolar concentrations of OTA promote apoptosis in a cell-type specific fashion. In this study, we have analyzed the molecular mechanism by which OTA affects COS cell adhesion and signaling resulting in an apoptotic response. OTA, at noncytotoxic doses, was able to detach collagen- and fibronectin-adherent cells from immobilized substratum. However, prior to inducing detachment of adherent cells, OTA caused apoptosis as measured by caspase-3 activation. The treatment of adherent cells by OTA caused a reduction of tyrosine phosphorylation levels of FAK and of the adapter protein paxillin. The down-regulation of FAK preceded apoptosis and cell detachment induced by OTA. The mycotoxin was also able to cause a decrease of the phosphorylation levels of the two Shc isoforms, P66 and P52, in adherent cells. Since these Shc isoforms have been implicated in the activation of protein kinase c-Src, which is required for FAK tyrosine phosphorylation, the observed dephosphorylation of FAK and of the FAK substrate paxillin by OTA could be ascribed to the early down-regulation of Shc isoforms. However, whether FAK and Shc phosphorylation contribute both to the same pathway leading to the induction of apoptosis by OTA or are involved in two parallel signaling pathways remains to be investigated.
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PMID:Ochratoxin A affects COS cell adhesion and signaling. 1457 39

Altered cellular adhesion and apoptotic signaling in cardiac remodeling requires coordinated regulation of multiple constituent proteins that comprise cytoskeletal focal adhesions. One such protein activated by cardiac remodeling is related adhesion focal tyrosine kinase (RAFTK, also known as pyk2). Adenoviral-mediated expression of RAFTK in neonatal rat cardiomyocytes involves concurrent increases in phosphorylation of Src, c-Jun N-terminal kinase, and p38 leading to characteristic apoptotic changes including cleavage of poly(ADP-ribose) polymerase, caspase-3 activation, and increased DNA laddering. DNA laddering was decreased by mutation of the Tyr(402) Src-binding site in RAFTK, suggesting a central role for Src activity in apoptotic cell death that was confirmed by adenoviral-mediated Src expression. Multiple apoptotic signaling cascades are recruited by RAFTK as demonstrated by prevention of apoptosis using caspase-3 inhibitor IV (caspase-3 specific inhibitor), PP2 (Src-specific kinase inhibitor), or Csk (cellular negative regulator for Src), as well as dominant negative constructs for p38beta or MKP-1. These RAFTK-mediated phenotypic characteristics are prevented by concurrent expression of wild-type or a phosphorylation-deficient paxillin mutated at Tyr(31) and Tyr(118). Wild-type or mutant paxillin protein accumulation in the cytoplasm has no overt effect upon cell structure, but paxillin accumulation prevents losses of myofibril organization as well as focal adhesion kinase, vinculin, and paxillin protein levels mediated by RAFTK. Apoptotic signaling cascade inhibition by paxillin indicates interruption of signaling proximal to but downstream of RAFTK activity. Chronic RAFTK activation in cardiac remodeling may represent a maladaptive reactive response that can be modulated by paxillin, opening up novel possibilities for inhibition of cardiomyocyte apoptosis and structural degeneration in heart failure.
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PMID:Cardiomyocyte apoptosis triggered by RAFTK/pyk2 via Src kinase is antagonized by paxillin. 1532 13

Although there are several agents that induce neutrophil apoptosis, few are known as inducers of eosinophil apoptosis. As eosinophils are potent effector cells contributing to allergic inflammation and asthma, we investigated whether the pro-apoptotic agent Viscum album agglutinin-I (VAA-I) could induce eosinophil apoptosis. VAA-I was found to induce apoptosis in eosinophilic AML14.3D10 (3D10) cells and that these cells expressed caspases-1, -2, -3, -4, -7, -8, -9 and -10. VAA-I-induced gelsolin degradation was reversed by the pan-caspase inhibitor N-benzyloxycarbonyl-V-A-D-O-methylfluoromethyl ketone (z-VAD). Also, paxillin, vimentin and lamin B1 were cleaved by caspases in VAA-I-induced 3D10 cells. VAA-I activated caspase-3 and -8 in 3D10 cells but, unlike z-VAD, treatment with a caspase-8 inhibitor slightly reversed apoptosis. Treatment of purified human eosinophils with VAA-I was found to induce apoptosis, degradation of gelsolin and lamin B1, but unlike 3D10 cells, cleavage of lamin B1 and cell apoptosis was not reversed by z-VAD. We conclude that VAA-I is a potent inducer of eosinophil apoptosis and that proteases other than those inhibited by z-VAD in 3D10 cells are involved in VAA-I-induced peripheral blood eosinophil apoptosis and lamin B1 cleavage. Thus, VAA-I represents a potential candidate for the reduction of the number of eosinophils in diseases where they play important roles.
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PMID:Viscum album agglutinin-I induces apoptosis and degradation of cytoskeletal proteins via caspases in human leukaemia eosinophil AML14.3D10 cells: differences with purified human eosinophils. 1609 66


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