Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

BAD is a Bcl-2 homology domain 3 (BH3)-only proapoptotic member of the Bcl-2 protein family that is regulated by phosphorylation in response to survival factors. Binding of BAD to mitochondria is thought to be exclusively mediated by its BH3 domain. We show here that BAD binds to lipids with high affinities, predominantly to negatively charged phospholipids, such as phosphatidylserine, phosphatidic acid, and cardiolipin, as well as to cholesterol-rich liposomes. Two lipid binding domains (LBD1 and LBD2) with different binding preferences were identified, both located in the C-terminal part of the BAD protein. BAD facilitates membrane translocation of Bcl-XL in a process that requires LBD2. Integrity of LBD1 and LBD2 is also required for proapoptotic activity in vivo. Phosphorylation of BAD does not affect membrane binding but renders BAD susceptible to membrane extraction by 14-3-3 proteins. BAD can be removed efficiently by 14-3-3zeta, -eta, -tau and lesxs efficiently by other 14-3-3 isoforms. The assembled BAD.14-3-3 complex exhibited high affinity for cholesterol-rich liposomes but low affinity for mitochondrial membranes. We conclude that BAD is a membrane-associated protein that has the hallmarks of a receptor rather than a ligand. Lipid binding is essential for the proapoptotic function of BAD in vivo. The data support a model in which BAD shuttles in a phosphorylation-dependent manner between mitochondria and other membranes and where 14-3-3 is a key regulator of this relocation. The dynamic interaction of BAD with membranes is tied to activation and membrane translocation of Bcl-XL.
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PMID:Reversible membrane interaction of BAD requires two C-terminal lipid binding domains in conjunction with 14-3-3 protein binding. 1660 46

Glucocorticoid excess induces hyperglycemia, which may result in diabetes. The present experiments explored whether glucocorticoids trigger apoptosis in insulin-secreting cells. Treatment of mouse beta-cells or INS-1 cells with the glucocorticoid dexamethasone (0.1 micromol/l) over 4 days in cell culture increased the number of fractionated nuclei from 2 to 7 and 14%, respectively, an effect that was reversed by the glucocorticoid receptor antagonist RU486 (1 micromol/l). In INS-1 cells, dexamethasone increased the number of transferase-mediated dUTP nick-end labeling-staining positive cells, caspase-3 activity, and poly-(ADP-) ribose polymerase protein cleavage; decreased Bcl-2 transcript and protein abundance; dephosphorylated the proapoptotic protein of the Bcl-2 family (BAD) at serine155; and depolarized mitochondria. Dexamethasone increased PP-2B (calcineurin) activity, an effect abrogated by FK506. FK506 (0.1 micromol/l) and another calcineurin inhibitor, deltamethrin (1 micromol/l), attenuated dexamethasone-induced cell death. The stable glucagon-like peptide 1 analog, exendin-4 (10 nmol/l), inhibited dexamethasone-induced apoptosis in mouse beta-cells and INS-1 cells. The protective effect of exendin-4 was mimicked by forskolin (10 micromol/l) but not mimicked by guanine nucleotide exchange factor with the specific agonist 8CPT-Me-cAMP (50 micromol/l). Exendin-4 did not protect against cell death in the presence of cAMP-dependent protein kinase (PKA) inhibition by H89 (10 micromol/l) or KT5720 (5 micromol/l). In conclusion, glucocorticoid-induced apoptosis in insulin-secreting cells is accompanied by a downregulation of Bcl-2, activation of calcineurin with subsequent dephosphorylation of BAD, and mitochondrial depolarization. Exendin-4 protects against glucocorticoid-induced apoptosis, an effect mimicked by forskolin and reversed by PKA inhibitors.
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PMID:Dexamethasone induces cell death in insulin-secreting cells, an effect reversed by exendin-4. 1664 95

Heme oxygenase (HO) plays a critical role in the regulation of cellular oxidative stress. The effects of the reactive oxygen species scavenger ebselen and the HO inducers cobalt protoporphyrin and stannous chloride (SnCl(2)) on HO protein levels and activity, indices of oxidative stress, and the progression of diabetes were examined in the Zucker rat model of type 2 diabetes. The onset of diabetes coincided with an increase in HO-1 protein levels and a paradoxical decrease in HO activity, which was restored by administration of ebselen. Up-regulation of HO-1 expressed in the early development of diabetes produced a decrease in oxidative/nitrosative stress as manifested by decreased levels of 3-nitrotyrosine, superoxide, and cellular heme content. This was accompanied by a decrease in endothelial cell sloughing and reduced blood pressure. Increased HO activity was also associated with a significant increase in the antiapoptotic signaling molecules Bcl-xl and phosphorylation of p38-mitogen-activated protein kinase but no significant increases in Bcl-2 or BAD proteins. In conclusion, 3-nitrotyrosine, cellular heme, and superoxide, promoters of vascular damage, are reduced by HO-1 induction, thereby preserving vascular integrity and protecting cardiac function involving an increase in antiapoptotic proteins.
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PMID:Up-regulation of heme oxygenase provides vascular protection in an animal model of diabetes through its antioxidant and antiapoptotic effects. 1695 61

PKCtheta regulates the proliferation, survival and differentiation of T-cells. Here we show that PKCtheta interacts with Raf-1 and B-Raf kinases. Raf-1 enhanced the kinase activity of associated PKCtheta, while PKCtheta reduced the catalytic activity of associated Raf-1. In contrast, B-Raf binding did not affect PKCtheta kinase activity, and PKCtheta did not change B-Raf activity. Coexpression of mutationally activated Raf-1 in cells enhanced the phosphorylation of T538 in the PKCtheta activation loop. PKCtheta and Raf cooperated in terms of binding to BAD, a pro-apoptotic Bcl-2 family protein that is inactivated by phosphorylation. While neither Raf-1 nor B-Raf could phosphorylate BAD, they enhanced the ability of PKCtheta to interact with BAD and to phosphorylate BAD in vitro and in vivo, suggesting a new role for Raf proteins in T-cells by targeting PKCtheta to interact with and phosphorylate BAD.
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PMID:Raf-1 and B-Raf promote protein kinase C theta interaction with BAD. 1701 51

Several lines of evidence indicate that, together with deregulated growth, alteration of apoptosis plays a pivotal role in tumorigenesis. PUMA, a pro-apoptotic member of Bcl-2 family, mediates p53-dependent and -independent apoptosis. BAD is also a pro-apoptotic Bcl-2 family member and phosphorylation of BAD protein inhibits the pro-apoptosis function of BAD. To see whether the alteration of protein expressions of PUMA and phospho-BAD (p-BAD) are characteristics of human colorectal cancers, we analyzed the expression of these proteins in 103 colorectal carcinomas by immunohistochemistry. Also, we analyzed the mutation of the Bcl-2 homology 3 (BH3) domain of PUMA gene, an important domain in the apoptosis function of PUMA, by single-strand conformation polymorphism (SSCP) in 98 colorectal carcinomas. p-BAD immunostaining was detected in 62 cases (60.1%) of the 103 carcinomas, whereas it was not detected in the normal colonic mucosal epithelial cells. PUMA protein expression was detected in both cancer cells and normal mucosal cells in all of the 103 cases. However, the cancer cells showed higher intensities of PUMA immunostaining than the normal cells of the same patients in 50.4% of the cases. There was no association of the p-BAD expression with the PUMA expression. The mutational analysis revealed no PUMA BH3 domain mutation in the cancers. Our data indicated that expressions of both PUMA and p-BAD were increased in the colorectal cancer cells, and suggested that the increased expression of these proteins in malignant colorectal epithelial cells compared to the normal mucosal epithelial cells may possibly alter the cell death regulation during colorectal tumorigenesis.
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PMID:Pro-apoptotic PUMA and anti-apoptotic phospho-BAD are highly expressed in colorectal carcinomas. 1739 17

Objective To investigate the effects of 14-3-3 protein overexpression on the 1-methyl-4-phenylpyridinium (MPP(+)) induced pheochromocytoma (PC12) cell death and the potential mechanisms. Methods pcDNA3.1(+)-14-3-3 plasmids, which could be expressed in mammalian cell, were constructed and transfected into PC12 cells with Lipofectamine 2000. The expression of 14-3-3 protein, Bcl-2 protein, and BAD protein were determined by western blot. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, microplate reader, and flow cytometric analysis were used to measure cell viability, the caspase activity, and apoptotic ratio respectively. Results (1) The expression of 14-3-3 protein increased significantly three weeks after pcDNA3.1 (+)-14-3-3 plasmids transfected into PC12 cells. (2) MPP(+) caused a decrease of cell viability in a dose-dependent manner. At 100 mu mol/L MPP(+), cell viability reduced approximately 50%. (3) The caspase activity increased along with the MPP(+) concentrations rising and reached its maximum value (0.34 mu mol/mg protein) at 100 mu mol/L MPP(+). However caspase activity decreased significantly when the MPP(+) concentration exceeded 100 mu mol/L. (4) Overexpression of 14-3-3 protein decreased the apoptosis ratio of PC12 cells treated with 100 mu mol/L MPP(+) from 26.5% to 8.6%. (5) Bcl-2 protein tended to decrease but BAD protein tended to increase after treatment of PC12 cells with 100 mu mol/L MPP(+). Overexpression of 14-3-3 protein significantly increased the cellular level of Bcl-2 protein and decreased that of BAD protein. Conclusion Overexpression of 14-3-3 protein may reduce MPP(+)-induced apoptotic cell death in PC12 cells by up-regulating the Bcl-2 expression and down-regulating the BAD expression. These results may provide a promising target for treatment of Parkinson' s disease.
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PMID:Overexpression of 14-3-3 protein protects pheochromocytoma cells against 1-methyl-4-phenylpyridinium toxicity. 1769 Jul 28

Mounting evidence indicates that deregulation of apoptosis contributes to the development of human cancers. BAD, a proapoptotic Bcl-2 family protein, regulates the intrinsic apoptosis pathway. The aim of this study was to explore whether alterations of phospho-BAD (p-BAD) protein that antagonizes apoptosis function of BAD and mutation of BAD gene are characteristics of human gastric cancers. We analyzed expression of p-BAD in 60 gastric adenocarcinomas by immunohistochemistry. Also, we analyzed BAD gene for detection of somatic mutations by single-strand conformation polymorphism (SSCP) assay. p-BAD expression was detected well in normal gastric mucosal epithelial cells, whereas it was detected in only 51% (31 of the 60) of the cancers. There was no somatic mutation of BAD gene in the 60 gastric cancer samples. The decreased expression of p-BAD in malignant gastric epithelial cells compared to normal mucosal epithelial cells suggested that loss of p-BAD expression may play a role in gastric tumorigenesis. The data also suggest that BAD mutation may not be a direct target of inactivation in gastric tumorigenesis.
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PMID:Immunohistochemical analysis of phospho-BAD protein and mutational analysis of BAD gene in gastric carcinomas. 1769 55

Apoptosis induced by oxidized low-density lipoproteins (oxLDL) and tumor necrosis factor-alpha (TNF-alpha) is believed to contribute to atherosclerosis and vascular dysfunction. Estrogen treatment reduces apoptosis due to TNF-alpha and we hypothesized that it would also reduce apoptosis due to oxLDL. We also explored the anti-apoptotic mechanisms. We used early passage human umbilical vein endothelial cells (HUVEC) grown in steroid-depleted, red phenol-free medium. Cells were synchronized by starvation for 6h and then treated with oxLDL (75microg/ml) or TNF-alpha (20ng/ml) in the presence of 17-beta-estradiol (E2) (20nM). Apoptosis was analyzed by flow cytometry and caspase-3 cleavage. We also assessed expression of Bcl-2 and Bcl-xL and phosphorylation of BAD. At 6h TNF-alpha induced apoptosis but oxLDL did not; E2 did not affect this TNF-alpha induced apoptosis and there was no change in Bcl-2 or Bcl-xL expression. At 24h both TNF-alpha and oxLDL increased apoptosis and E2 reduced the increase. E2 also increased expression of the anti-apoptotic Bcl-2 and Bcl-xL and increased phosphorylation of proapoptotic BAD which reduces its proapoptotic activity at 1h. However at 24h there was also an increase in total BAD so that the proportion of phosphorylation of BAD decreased. oxLDL induced apoptosis occurs later than that of TNF-alpha. E2 decreased this late phase apoptosis and this likely requires the production of anti-apoptotic proteins.
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PMID:Estrogen decreases TNF-alpha and oxidized LDL induced apoptosis in endothelial cells. 1793 19

H2O2, as an example of oxidative stress, induces cardiac myocyte apoptosis. Bcl-2 family proteins are key regulators of the apoptotic response while their functions can be regulated by post-translational modifications including phosphorylation, dimerization or proteolytic cleavage. In this study, we examined the role of various protein kinases in regulating total BAD protein levels in adult rat cardiac myocytes undergoing apoptosis. Stimulation with 0.1 mM H2O2, which induces apoptosis, resulted in a marked down-regulation of BAD protein, which is attributed to cleavage by caspases since it can be restored in the presence of a general caspase inhibitor. Inhibition of PKC, p38-MAPK, ERK1/2 and PI-3-K did not influence the reduced BAD protein levels observed after stimulation with H2O2. On the contrary, inhibition of PKA or specifically PKCdelta resulted in up-regulation of BAD. Decreased caspase 3 activity was observed in H2O2 treated cells after inhibition of PKA or PKCdelta whereas inhibition of PKA also resulted in improved cell survival. Furthermore, addition of okadaic acid to inhibit selected phosphatases resulted in enhanced BAD cleavage. These data suggest that, during oxidative stress-induced cardiac myocyte apoptosis, there is a caspase-dependent down-regulation of BAD protein, which seems to be regulated by coordinated action of PKA, PKCdelta and phosphatases.
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PMID:Regulation of BAD protein by PKA, PKCdelta and phosphatases in adult rat cardiac myocytes subjected to oxidative stress. 1797 75

There is growing evidence that accelerated telomeric attrition and/or aberrant telomerase activity contributes to pathogenesis in a number of diseases. Likewise, there is increasing interest to develop new therapies to restore or replace dysfunctional cells characterized by short telomeric length using telomerase-positive counterparts or stem cells. While telomerase adds telomeric repeats de novo contributing to enhanced proliferative capacity and lifespan, it may also increase cellular survival by conferring resistance to apoptosis. Consequently, we sought to determine the involvement of telomerase for reduced apoptosis using ovarian surface epithelial cells. We found that expression of hTERT, the catalytic component of telomerase, was sufficient and specific to reduce caspase-mediated cellular apoptosis. Further, hTERT expression reduced activation of caspases 3, 8, and 9, reduced expression of pro-apoptotic mitochondrial proteins t-BID, BAD, and BAX and increased expression of the anti-apoptotic mitochondrial protein, Bcl-2. The ability of telomerase to suppress caspase-mediated apoptosis was p-jnk dependent since abrogation of jnk expression with jip abolished resistance to apoptosis. Consequently, these findings indicate that telomerase may promote cellular survival in epithelial cells by suppressing jnk-dependent caspase-mediated apoptosis.
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PMID:Telomerase confers resistance to caspase-mediated apoptosis. 1804 12


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