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

Tautomycetin (TMC) was identified as an immunosuppressor of activated T cells. Inhibition of T cell proliferation with TMC was observed at concentrations 100-fold lower than those needed to achieve maximal inhibition with cyclosporin A (CsA). TMC specifically blocked tyrosine phosphorylation of intracellular signal mediators downstream of Src tyrosine kinases in a T cell-specific manner, leading to apoptosis due to cleavage of Bcl-2, caspase-9, caspase-3, and poly(ADP-ribose) polymerase, but not caspase-1. In TMC-treated rats that received a heterotopic cardiac allograft, the graft survived more than 160 days, comparable to graft survival in allografted rats treated with CsA. Thus, TMC, whose mechanism of action is different from that of CsA or FK506, can be used as a potent T cell-specific immunosuppressor.
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PMID:Immunosuppressive effects of tautomycetin in vivo and in vitro via T cell-specific apoptosis induction. 1214 81

The mitochondrial localization of the membrane proteins Bcl-2 and Bcl-x(L) is essential for their anti-apoptotic function. Here we show that mitochondrial FK506-binding protein 38 (FKBP38), unlike FKBP12, binds to and inhibits calcineurin in the absence of the immunosuppressant FK506, suggesting that FKBP38 is an inherent inhibitor of this phosphatase. FKBP38 is associated with Bcl-2 and Bcl-x(L) in immunoprecipitation assays and colocalizes with these proteins in mitochondria; in addition, the expression of FKBP38 mutant proteins induces a marked redistribution of Bcl-2 and Bcl-x(L). Overexpression of FKBP38 blocks apoptosis, whereas functional inhibition of this protein by a dominant-negative mutant or by RNA interference promotes apoptosis. Thus, FKBP38 might function to inhibit apoptosis by anchoring Bcl-2 and Bcl-x(L) to mitochondria.
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PMID:Inherent calcineurin inhibitor FKBP38 targets Bcl-2 to mitochondria and inhibits apoptosis. 1251 82

Proteins synthesized in the cytosol can be inserted into or across organellar membranes depending on the signals present in their primary sequences. Proteins of the Bcl-2 family, which includes proteins that promote programmed cell death (apoptosis) and proteins that inhibit apoptosis, have signals that can target particular members to either the mitochondria or the endoplasmic reticulum (ER) or both. Germain and Shore discuss evidence for a role for the anti-apoptotic members of the family at the ER and describe an interaction with the FK506 binding protein, FKBP38, that may regulate the relative distribution of Bcl-2 proteins at the ER or mitochondria. This interaction may control the cell's sensitivity to apoptotic stimuli.
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PMID:Cellular distribution of Bcl-2 family proteins. 1263 89

In cyanide-induced apoptosis, an increase in cytosolic free Ca2+ and generation of reactive oxygen species are initiation stimuli for apoptotic cell death. Previous studies have shown that cyanide-stimulated translocation of Bax (Bcl-associated X protein) to mitochondria is linked with release of cytochrome c and subsequent activation of a caspase cascade [Shou, Li, Prabhakaran, Borowitz and Isom (2003) Toxicol. Sci. 75, 99-107]. In the present study, the relationship of the cyanide-induced increase in cytosolic free Ca2+ to activation of Bad ( Bcl-2/Bcl-X(L)- antagonist, causing cell death) was determined in cortical cells. Bad is a Ca2+-sensitive pro-apoptotic Bcl-2 protein, which on activation translocates from cytosol to mitochondria to initiate cytochrome c release. In cultured primary cortical cells, cyanide produced a concentration- and time-dependent translocation of Bad from cytosol to mitochondria. Translocation occurred early in the apoptotic response, since mitochondrial Bad was detected within 1 h of cyanide treatment. Mitochondrial levels of the protein continued to increase up to 12 h post-cyanide exposure. Concurrent with Bad translocation, a Ca2+-sensitive increase in cellular calcineurin activity was observed. Increased cytosolic Ca2+ and calcineurin activation stimulated Bad translocation since BAPTA [bis-(o-aminophenoxy)ethane-N, N, N', N'-tetra-acetic acid], an intracellular Ca2+ chelator, and cyclosporin A, a calcineurin inhibitor, significantly reduced translocation. BAPTA also blocked release of cytochrome c from mitochondria as well as apoptosis. Furthermore, treatment of cells with the calcineurin inhibitors cyclosporin A or FK506 blocked the apoptotic response, linking calcineurin activation and the subsequent translocation of Bad to cell death. These observations show that by inducing a rapid increase in cytosolic free Ca2+, cyanide can partially initiate the apoptotic cascade through a calcineurin-mediated translocation of Bad to mitochondria.
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PMID:Calcineurin-mediated Bad translocation regulates cyanide-induced neuronal apoptosis. 1474 Oct 51

Various apoptotic stimuli induce mitochondrial dysfunction. Bcl-2 and Bcl-xL antagonize apoptosis by blocking the release of caspase activators such as cytochrome c from mitochondria. We demonstrated that FKBP38, a member of the immunophilin family, interacts and targets these anti-apoptotic proteins Bcl-2 and Bcl-xL, thereby assisting them in their pro-survival role. FKBP38 is specifically localized on mitochondria, at which FKBP38 is colocalized with Bcl-2 and Bcl-xL. Expression of exogenous FKBP38 promotes mitochondrial targeting of Bcl-2 and Bcl-xL, while dominant-negative FKBP38 or siRNA of FKBP38 disturbs their localization. On the other hand, unlike FKBP12, FKBP38 inhibits serine/threonine phosphatase calcineurin in an FK506-independent manner. Overexpression of FKBP38 inhibits apoptosis, while expression of dominant-negative FKBP38 or depletion of endogenous FKBP38 increases the sensitivity for apoptosis. Thus, FKBP38 has unique features among members of the immunophilin family.
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PMID:[Immunophilin FKBP38, an inherent inhibitor of calcineurin, targets Bcl-2 to mitochondria and inhibits apoptosis]. 1496 53

Bim, a proapoptotic BH3-only member of the Bcl-2 protein family, is required for central and peripheral deletion of T lymphocytes. Mechanisms regulating Bim activity in T cells remain poorly understood. We show that expression of Bim is up-regulated in human T cells after polyclonal or specific T cell receptor triggering. Induction of Bim was affected by the agonistic potency of MHC:peptide ligands. Peptides that failed to induce Bim expression, failed to induce apoptosis in specific T cells, whereas partially agonistic ligands, which trigger death receptor-independent activation-induced cell death (AICD), induced Bim, but were inefficient in up-regulating Bcl-X(L). Activation of protein kinase C and calcineurin appeared to be necessary and sufficient for Bim up-regulation after T cell receptor ligation. Immunosuppressive drugs known to prevent T cell deletion in vivo, such as cyclosporin A or FK506, blocked Bim up-regulation and rescued T cells from death receptor-independent AICD, whereas rapamycin, which allows the development of stable immunological tolerance, did not exhibit these activities. These results define a new mode of Bim regulation, strongly implicate Bim as a mediator of AICD, and suggest that Bim up-regulation can be targeted to influence the outcome of specific immune responses.
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PMID:Regulation of expression of Bcl-2 protein family member Bim by T cell receptor triggering. 1497 Mar 29

Mice expressing an error-prone mitochondrial DNA polymerase rapidly accumulate random mutations in mitochondrial DNA. Expression of the transgene in the heart leads to dilated cardiomyopathy accompanied by a wave of apoptosis in cardiomyocytes, and a vigorous and persistent protective response, including upregulation of the anti-apoptotic protein, Bcl-2. To investigate the role of the mitochondrial permeability transition pore in the development of disease, we treated mice with cyclosporin A (CsA), an inhibitor of pore opening. Drug treatment prevented cardiac dilatation, transgene-specific apoptosis, and upregulation of Bcl-2. It also rescued hearts from the profound decrease in connexin 43, which characterizes the dilatated heart. Treatment with FK506, which like CsA inhibits cytoplasmic calcineurin but not the mitochondrial pore, did not affect disease development, suggesting that the relevant target of CsA was the mitochondrial pore. These data implicate breakdowns in the mitochondrial permeability barrier in pathogenesis of elevated frequencies of mtDNA mutations.
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PMID:Cardiac disease due to random mitochondrial DNA mutations is prevented by cyclosporin A. 1519 95

Transcription of the genes Granzyme A (GZMA), FK506 binding protein 51 (FKBP5), and Down syndrome critical region gene 1 (DSCR1) is upregulated in leukemic cells upon treatment with glucocorticoids (GCs). Several lines of evidence suggest that these genes are implicated in GC-induced apoptosis upstream of the Bcl-2 family of proteins. These genes were upregulated by GC even in the presence of an inhibitor of protein synthesis, cycloheximide, indicating that they are direct target genes of glucocorticoid receptors. DSCR1 is reported to have four isoforms, each of which has a distinct first exon, E1-E4. Among these isoforms, the one with E1 was selectively upregulated by GC. GZMA and FKBP5 have a cluster of putative glucocorticoid response elements (GREs) in introns 1 and 2, respectively, that was identified to be responsible for the response to GC. They were composed of one complete (A/T)G(A/T)(A/T)C(A/T) sequence surrounded by two incomplete (A/T)G(A/T)(A/T)C(A/T) sequences separated by one to four nucleotides. DSCR1, however, did not have a functional GRE upstream or downstream of exon 1. These studies may lead to improved therapeutic uses of GCs in leukemia and lymphoma based upon the expression of these GC target genes.
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PMID:Identification of novel direct transcriptional targets of glucocorticoid receptor. 1538 27

The mitochondrial toxin 3-nitropropionic acid (3-NP) has been largely used to study neurodegenerative disorders in which bioenergetic defects are implicated. In the present study, we analyzed the molecular pathways involved in FK506 neuroprotection against cell death induced by 3-NP, using cultured cortical neurons. 3-NP induced cytochrome c release and increased caspases -2, -3, -8, and -9-like activities, although, calpain activity was not significantly affected. FK506 decreased cytochrome c release and caspase-3-like activity induced by 3-NP, without changing the activities of other caspases. FK-506 also decreased the number of apoptotic neurons, determined by Hoechst. Under these conditions, FK506 alone significantly reduced calcineurin activity by about 50%. Our results also showed a decrease in mitochondrial Bax and an increase in mitochondrial Bcl-2 levels upon exposure to FK506 and 3-NP. However, no significant changes occurred in total Bcl-2 and Bax levels. Altogether, the results suggest that FK506 neuroprotection against 3-NP-induced apoptosis is associated with the redistribution of Bcl-2 and Bax in the mitochondrial membrane.
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PMID:FK506 prevents mitochondrial-dependent apoptotic cell death induced by 3-nitropropionic acid in rat primary cortical cultures. 1557 79

The mechanism of action of the neurotoxin 6-hydroxydopamine (6-OHDA) is thought to involve the generation of free radicals and subsequent apoptotic processes. We have demonstrated in vitro that the neuroimmunophilin, FK506 (10-100 nM), dose dependently and significantly restored the ROS production to the control level, increased the Bcl-2 protein level, partly inhibited the cytochrome C release from mitochondria and reduced the caspase-3 activation in SH-SY5Y cells. On the other hand, there was no significant restoration of the ATP level by FK506 and the toxin activated proteins, p53 and Bax, were not normalized by FK506. In support of these latter results, daily administration of FK506 for 7 days to rats (0.5, 1 and 3 mg/kg i.p.) did not significantly prevent the apomorphine-induced contralateral circling, measured 2 weeks after unilateral nigral lesioning. Moreover, FK506 pretreatment did not significantly lower the toxin elevated lipid peroxidation levels, indicating that oxidative stress was present even after the FK506 treatment in the lesioned striatum. Taken together, our results with FK506 are inconsistent. We confirm the antioxidant nature of FK506, that is, it blocks ROS production in SH-SY5Y cells. However, there were no significant protective effects in any apoptotic analyses in SH-SY5Y cells and in animal studies, a 7-day FK506 pre-treatment was not able to reverse the toxic effect of 6-OHDA in a rat model of Parkinson's disease.
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PMID:Failure of FK506 (tacrolimus) to alleviate apomorphine-induced circling in rat Parkinson model in spite of some cytoprotective effects in SH-SY5Y dopaminergic cells. 1574 76


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