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)

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

The microbial peptidomacrolide FK506 affects many eukaryotic developmental and cell signaling programs via calcineurin inhibition. Prior formation of a complex between FK506 and intracellular FK506-binding proteins (FKBPs) is the precondition for the interaction with calcineurin. A puzzling difference has emerged between the mammalian multidomain protein hFKBP38 and other FKBPs. It was shown that hFKBP38 not only binds to calcineurin but also inhibits the protein phosphatase activity of calcineurin on its own [Shirane, M. and Nakayama, K.I. (2003) Nature Cell Biol. 5, 28-37]. Inherent calcineurin inhibition by hFKBP38 would completely eliminate the need for FK506 in controlling many signal transduction pathways. To address this issue, we have characterized the functional and physical interactions between calcineurin and hFKBP38. A recombinant hFKBP38 variant and endogenous hFKBP38 were tested both in vitro and in vivo. The proteins neither directly inhibited calcineurin activity nor affected NFAT reporter gene activity in SH-SY5Y and Jurkat cells. In addition, a direct physical interaction between calcineurin and hFKBP38 was not detected in co-immunoprecipitation experiments. However, hFKBP38 indirectly affected the subcellular distribution of calcineurin by interaction with typical calcineurin ligands, as exemplified by the anti-apoptotic protein Bcl-2. Our data suggest that hFKBP38 cannot substitute for the FKBP/FK506 complex in signaling pathways controlled by the protein phosphatase activity of calcineurin.
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PMID:A reassessment of the inhibitory capacity of human FKBP38 on calcineurin. 1575 46

FKBP-type peptidyl prolyl cis/trans isomerases (PPIases) are folding helper enzymes involved in the control of functional regrowth of damaged sciatic, cortical cholinergic, dopaminergic and 5-HT neurones. Here, we show that the constitutively inactive human FK506-binding protein 38 (FKBP38) is capable of responding directly to intracellular Ca2+ rise through formation of a heterodimeric Ca2+/calmodulin/FKBP38 complex. Only complex formation creates an enzymatically active FKBP, displaying affinity for Bcl-2 mediated through the PPIase site. Association between Bcl-2 and the active site of Ca2+/calmodulin/FKBP38 regulates Bcl-2 function and thereby participates in the promotion of apoptosis in neuronal tissues. FKBP38 proapoptotic function mediated by this interaction is abolished by either potent inhibitors of the PPIase activity of the Ca2+/calmodulin/FKBP38 complex or RNA interference-mediated depletion of FKBP38, promoting neuronal cell survival.
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PMID:Bcl-2 regulator FKBP38 is activated by Ca2+/calmodulin. 1599 Aug 72

The FK506-binding protein 38 (FKBP38) affects neuronal apoptosis control by suppressing the anti-apoptotic function of Bcl-2. The direct interaction between FKBP38 and Bcl-2, however, requires a prior activation of FKBP38 by the Ca2+ sensor calmodulin (CaM). Here we demonstrate for the first time that the formation of a complex between FKBP38 and CaM-Ca2+ involves two separate interaction sites, thus revealing a novel scenario of target protein regulation by CaM-Ca2+. The C-terminal FKBP38 residues Ser290-Asn313 bind to the target protein-binding cleft of the Ca2+-coordinated C-terminal CaM domain, thereby enabling the N-terminal CaM domain to interact with the catalytic domain of FKBP38 in a Ca2+-independent manner. Only the latter interaction between the catalytic FKBP38 domain and the N-terminal CaM domain activates FKBP38 and, as a consequence, also regulates Bcl-2.
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PMID:A novel calmodulin-Ca2+ target recognition activates the Bcl-2 regulator FKBP38. 1794 10

The FK506-binding protein 38 (FKBP38) is a pro-apoptotic regulator of Bcl-2 in neuroblastoma cells. Hsp90 inhibits the pro-apoptotic FKBP38/CaM/Ca(2+) complex and thus prevents interactions between FKBP38 and Bcl-2. Here we show that Hsp90 increases cell survival rates of neuroblastoma cells after apoptosis induction. Depletion of FKBP38 by short interference RNA significantly decreased the anti-apoptotic effect of Hsp90 expression. In addition, the influence of high cellular Hsp90 levels was only observed in post-stimulation apoptosis that is sensitive to selective FKBP38 active site inhibition. Similar anti-apoptotic effects in neuroblastoma cells were observed after stimulation of endogenous Hsp90 expression. Hence, the inhibition of FKBP38 by Hsp90 participates in programmed cell death control of neuroblastoma cells.
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PMID:Hsp90-mediated inhibition of FKBP38 regulates apoptosis in neuroblastoma cells. 1803 48

FKBP38 (also known as FKBP8) is a transmembrane chaperone protein that inhibits apoptosis by recruiting the anti-apoptotic proteins Bcl-2 and Bcl-x(L) to mitochondria. We have now generated mice harboring a loss-of-function mutation in Fkbp38. The Fkbp38(-/-) mice die soon after birth manifesting defects in neural tube closure in the thoraco-lumbar-sacral region (spina bifida) as well as skeletal defects including scoliosis, rib deformities, club foot and curled tail. The neuroepithelium is disorganized and that formation of dorsal root ganglia is defective in Fkbp38(-/-) embryos, likely as a result of an increased frequency of apoptosis and aberrant migration of neuronal cells. Furthermore, the extension of nerve fibers in the spinal cord is abnormal in the mutant embryos. To explore the mechanisms underlying these characteristics, we screened for proteins that interact with FKBP38 in the yeast two-hybrid system and thereby identified protrudin, a protein that promotes process formation by regulating membrane trafficking. Protrudin was found to be hyperphosphorylated in the brain of Fkbp38(-/-) mice, suggesting that FKBP38 regulates protrudin-dependent membrane recycling and neurite outgrowth. Together, our findings suggest that FKBP38 is required for neuroectodermal organization during neural tube formation as a result of its anti-apoptotic activity and regulation of neurite extension.
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PMID:Regulation of apoptosis and neurite extension by FKBP38 is required for neural tube formation in the mouse. 1845 60

The cellular processes that regulate Bcl-2 at the posttranslational levels are as important as those that regulate bcl-2 synthesis. Previously we demonstrated that the suppression of FK506-binding protein 38 (FKBP38) contributes to the instability of Bcl-2 or leaves Bcl-2 unprotected from degradation in an unknown mechanism. Here, we studied the underlying molecular mechanism mediating this process. We first showed that Bcl-2 binding-defective mutants of FKBP38 fail to accumulate Bcl-2 protein. We demonstrated that the FKBP38-mediated Bcl-2 stability is specific as the levels of other anti-apoptotic proteins such as Bcl-X(L) and Mcl-1 remained unaffected. FKBP38 enhanced the Bcl-2 stability under the blockade of de novo protein synthesis, indicating it is posttranslational. We showed that the overexpression of FKBP38 attenuates reduction rate of Bcl-2, thus resulting in an increment of the intracellular Bcl-2 level, contributing to the resistance of apoptotic cell death induced by the treatment of kinetin riboside, an anticancer drug. Caspase inhibitors markedly induced the accumulation of Bcl-2. In caspase-3-activated cells, the knockdown of endogenous FKBP38 by small interfering RNA resulted in Bcl-2 down-regulation as well, which was significantly recovered by the treatment with caspase inhibitors or overexpression of FKBP38. Finally we presented that the Bcl-2 cleavage by caspase-3 is blocked when Bcl-2 binds to FKBP38 through the flexible loop. Taken together, these results suggest that FKBP38 is a key player in regulating the function of Bcl-2 by antagonizing caspase-dependent degradation through the direct interaction with the flexible loop domain of Bcl-2, which contains the caspase cleavage site.
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PMID:FKBP38 protects Bcl-2 from caspase-dependent degradation. 2013 69

The human FK506-binding protein 38 (FKBP38) regulates Bcl-2 in neuronal apoptosis. To control Bcl-2 activity, FKBP38 requires a prior interaction with the Ca(2+)-sensor calmodulin (CaM). The resulting FKBP38/CaM complex is unique within the FKBP family. Here, we present novel insights into the structural arrangement of this complex. Chemical shift perturbation analyses of the individual protein domains revealed two separate interaction sites between FKBP38 and CaM. On the one hand, residues Glu303, Tyr307 and Leu311, belonging to the predicted CaM-binding site at the C-terminal end of FKBP38, become embedded in the hydrophobic target protein-binding cleft of the C-terminal CaM lobe. On the other hand, in a second binding interaction, the N-terminal end of the catalytic FKBP38 domain shows surface contacts to the AB and CD loops of CaM as well as the adjacent helices. Furthermore, a Glu-rich region at the non-structured FKBP38 N-terminus features additional contacts to CaM helix A. In combination with previous results, we thus conclude that the FKBP38/CaM complex is constituted by (i) a Ca(2+)-dependent interaction of the CaM-binding motif at the C-terminal end of FKBP38 with the C-terminal CaM lobe and (ii) a Ca(2+)-independent interaction between the N-terminal CaM lobe and the N-terminal region of the catalytic FKBP38 domain.
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PMID:New structural aspects of FKBP38 activation. 2070 7

FKBP38 (FK506-binding protein 38), a membrane-anchored TPR (tetratricopeptide repeat)-containing immunophilin, regulates signalling pathways such as cell survival, apoptosis, proliferation and metastasis. However, the mechanisms that regulate the activity of FKBP38 are, at present, poorly understood. We previously reported that Ca2+/S100 proteins directly associate with the TPR proteins, such as Hop [Hsp70 (heat-shock protein of 70 kDa)/Hsp90-organizing protein], kinesin-light chain, Tom70 (translocase of outer mitochondrial membrane 70), FKBP52, CyP40 (cyclophilin 40), CHIP (C-terminus of Hsc70-interacting protein) and PP5 (protein phosphatase 5), leading to the dissociation of the interactions of the TPR proteins with their target proteins. Therefore we have hypothesized that Ca2+/S100 proteins can interact with FKBP38 and regulate its function. In vitro binding studies demonstrated that S100A1, S100A2, S100A6, S100B and S100P specifically interact with FKBP38 and inhibit the interaction of FKBP38 with Bcl-2 and Hsp90. Overexpression of permanently active S100P in Huh-7 cells inhibited the interaction of FKBP38 with Bcl-2, resulting in the suppression of Bcl-2 stability. The association of the S100 proteins with FKBP38 provides a Ca2+-dependent regulatory mechanism of the FKBP38-mediated signalling pathways.
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PMID:Ca2+/S100 proteins inhibit the interaction of FKBP38 with Bcl-2 and Hsp90. 2429 50

FK506-binding protein 38 (FKBP38) is a membrane chaperone that is localized predominantly to mitochondria and contains a COOH-terminal tail anchor. FKBP38 also harbors an FKBP domain that confers peptidyl-prolyl cis-trans isomerase activity, but it differs from other FKBP family members in that this activity is dependent on the binding of Ca(2+)-calmodulin. FKBP38 inhibits apoptosis by recruiting the anti-apoptotic proteins Bcl-2 and Bcl-xL to mitochondria. Mice deficient in FKBP38 die soon after birth manifesting a defect in neural tube closure that results in part from unrestrained apoptosis. We recently found that FKBP38 and Bcl-2 translocate from mitochondria to the endoplasmic reticulum during mitophagy, a form of autophagy responsible for the elimination of damaged mitochondria. FKBP38 and Bcl-2 thus escape the degradative fate of most mitochondrial proteins during mitophagy. This escape of FKBP38 is dependent on the low basicity of its COOH-terminal sequence and is essential for the suppression of apoptosis during mitophagy. FKBP38 thus plays a key role in the regulation of apoptosis under normal and pathological conditions.
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PMID:Mitochondria: FKBP38 and mitochondrial degradation. 2465 51


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