Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Work in Saccharomyces cerevisiae and Cryptococcus neoformans suggests that caspofungin could interact with the calcineurin pathway. We examined the in vitro interaction of caspofungin with calcineurin inhibitors (FK506, cyclosporin, FK520 and L685,818) and the TOR inhibitor rapamycin in 13 isolates of Aspergillus species. Caspofungin activity was enhanced by calcineurin/TOR inhibitors for all Aspergillus isolates studied. Further investigation of this pathway is warranted.
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PMID:Combination of caspofungin with inhibitors of the calcineurin pathway attenuates growth in vitro in Aspergillus species. 1256 96

The TOR (target of rapamycin) and RAS/cyclic AMP (cAMP) signaling pathways are the two major pathways controlling cell growth in response to nutrients in yeast. In this study we examine the functional interaction between TOR and the RAS/cAMP pathway. First, activation of the RAS/cAMP signaling pathway confers pronounced resistance to rapamycin. Second, constitutive activation of the RAS/cAMP pathway prevents several rapamycin-induced responses, such as the nuclear translocation of the transcription factor MSN2 and induction of stress genes, the accumulation of glycogen, the induction of autophagy, the down-regulation of ribosome biogenesis (ribosomal protein gene transcription and RNA polymerase I and III activity), and the down-regulation of the glucose transporter HXT1. Third, many of these TOR-mediated responses are independent of the previously described TOR effectors TAP42 and the type 2A-related protein phosphatase SIT4. Conversely, TOR-controlled TAP42/SIT4-dependent events are not affected by the RAS/cAMP pathway. Finally, and importantly, TOR controls the subcellular localization of both the protein kinase A catalytic subunit TPK1 and the RAS/cAMP signaling-related kinase YAK1. Our findings suggest that TOR signals through the RAS/cAMP pathway, independently of TAP42/SIT4. Therefore, the RAS/cAMP pathway may be a novel TOR effector branch.
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PMID:Activation of the RAS/cyclic AMP pathway suppresses a TOR deficiency in yeast. 1467 67

Calcineurin inhibitors potentially contribute to risk of cardiovascular events through the development of new-onset diabetes mellitus, hypertension and hyperlipidemia. The exact extent to which calcineurin inhibitors affect these risk factors is difficult to establish since pre-existing renal disease and concomitant immunosuppressive agents (such as steroids or TOR inhibitors) also exert an effect. Clinical trials have consistently shown a higher incidence of new-onset diabetes mellitus with tacrolimus, which has been borne out in large-scale registry analyses. However, the risk of hypertension is approximately 5% higher with cyclosporine than tacrolimus, as is the risk of hyperlipidemia. Statin therapy is effective in treating dyslipidemia and has significant benefits in renal transplant patients. An individualized approach to choice of calcineurin inhibitor, by which cyclosporine or tacrolimus are selected based on the patient's particular risk profile, may thus help to reduce the toll of cardiovascular mortality among renal transplant recipients in the future.
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PMID:Assessing the relative risk of cardiovascular disease among renal transplant patients receiving tacrolimus or cyclosporine. 1577 54

Expression of HXT1, a gene encoding a Saccharomyces cerevisiae low-affinity glucose transporter, is regulated by glucose availability, being activated in the presence of glucose and inhibited when the levels of the sugar are scarce. In this study we show that 14-3-3 proteins are involved in the regulation of the expression of HXT1 by glucose. We also demonstrate that 14-3-3 proteins, in complex with Reg1, a regulatory subunit of Glc7 protein phosphatase, interact physically with Grr1 (a component of the SCF-Grr1 ubiquitination complex), a key player in the process of HXT1 induction by glucose. In addition, we show that the TOR kinase pathway participates actively in the induction of HXT1 expression by glucose. Inhibition of the TOR kinase pathway by rapamycin treatment abolishes HXT1 glucose induction. A possible involvement of PP2A protein phosphatase complex, through the Cdc55 B-subunit, in the glucose induction of HXT1 is also discussed.
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PMID:TOR kinase pathway and 14-3-3 proteins regulate glucose-induced expression of HXT1, a yeast low-affinity glucose transporter. 1584 87

Effective immunosuppression is an essential pre-requisite for successful organ transplantation and improvements in outcome after transplantation have to a large extent been dependent on developments in immunosuppressive therapy. Here we provide an overview of the different immunosuppressive agents currently used in solid organ transplantation. A historical perspective on the development of immunosuppression for organ transplantation is followed by a review of the individual agents, with a focus on their mechanism of action and efficacy. Steroids, anti-proliferative agents (azathioprine and mycophenolate), calcineurin inhibitors (cyclosporine and tacrolimus) and TOR inhibitors (sirolimus and everolimus) are discussed along with both polyclonal and monoclonal antibody preparations. Many of the key clinical trials that underpin current clinical usage of these agents are described and side-effects of the different agents are highlighted. Finally, a number of newer agents still in various stages of clinical development are briefly considered.
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PMID:Immunosuppressive agents in solid organ transplantation: Mechanisms of action and therapeutic efficacy. 1603 69

Post-transplant de novo malignancies are reviewed in three time periods: (i) the azathioprine (AZA) era from 1962 to 1980-1981, (ii) the cyclosporine (CYA) era (1980 to present) in which the calcineurin inhibitors, CYA and tacrolimus (TAC), were the mainstay of recipient immunosuppression, and (iii) the TOR inhibitor era starting in the year 2000. Both transplant registry and transplant center reports on malignancies occurring in the AZA era are reviewed. Reports from transplant centers and from the Cincinnati Transplant Tumor Registry (CTTR) in both the early CYA era (1980s) and the 1900-2000 CYA era are reported. Cancer incidence associated with AZA versus CYA, CYA versus TAC, and AZA versus mycophenolate mofetil (MMF) is compared in both transplant center and registry reports including new, unreported Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) data from 1998 to 2003. The malignancy incidence associated with lymphocyte-depleting antibody and corticosteroid immunosuppression is discussed. Reduced malignancy incidence recently reported with TOR inhibitors is compared with that of conventional immunosuppression. Important nondrug factors influencing the incidence of post-transplant malignancies from seven single and three registry reports are detailed. The substantial role that de novo malignancies play in post-transplant mortality is discussed. Finally, management recommendations for recipients who develop de novo post-transplant malignancies are briefly presented.
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PMID:Post-transplant de novo malignancies in renal transplant recipients: the past and present. 1682 77

Although short-term kidney allograft survival has improved significantly since the introduction of the calcineurin inhibitors (CNI) cyclosporine A (CsA) and tacrolimus, long-term transplant survival remains a major concern, chronic allograft nephropathy (CAN) being the principal reason for graft loss after the first post-transplant year. This is particularly major for pediatric renal transplant recipients because of their higher life expectancy compared with adults. The mechanisms leading to CAN are multiple, including acute and chronic alloimmune responses and nephrotoxicity of CNIs. CNI-induced nephrotoxicity is also a long-term concern in other pediatric solid organ transplant recipients, such as liver and heart. Prevention of allograft nephropathy requires a balance of maintaining adequate immunosuppression, while avoiding the toxic effects of CNIs. Regimens that are based on mycophenolate mofetil (MMF) alone or in combination with newer agents may allow for reduced reliance on CNIs and thus may represent an effective treatment paradigm for long-term maintenance of a renal allograft. From the available data it appears that the currently safest treatment strategy in pediatric renal and heart transplant recipients with CNI toxicity is an MMF-based therapy with low-dose CNIs +/- low-dose steroids, while in pediatric liver transplant recipients, CNI-free MMF-based immunosuppressive therapy with or without steroids appears feasible in a significant subset of patients. In renal transplant recipients, the benefit of a CNI-free MMF/steroid therapy on renal function is gained at the cost of increased rejection in a subset of patients, although the relative importance of rejection vs. overall renal function requires further clinical investigation. The introduction of mammalian target of rapamycin (mTOR) inhibitors provides an opportunity for unique CNI-sparing regimens that combine two antiproliferative agents (MMF and TOR inhibitors). It is possible that a sirolimus-based CNI-free immunosuppressive regimen in terms of renal transplant survival is superior to CNI minimization, where the detrimental effects of CNIs on allograft function and structure are still operative, albeit to a lesser degree. Substitution of CNIs by mTOR inhibitors is therefore promising, but requires validation in long-term studies in large cohorts.
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PMID:Treatment strategies in pediatric solid organ transplant recipients with calcineurin inhibitor-induced nephrotoxicity. 1691 97

Synthetic genetic array analyses identify powerful genetic interactions between a thermosensitive allele (sec14-1(ts)) of the structural gene for the major yeast phosphatidylinositol transfer protein (SEC14) and a structural gene deletion allele (tlg2Delta) for the Tlg2 target membrane-soluble N-ethylmaleimide-sensitive factor attachment protein receptor. The data further demonstrate Sec14 is required for proper trans-Golgi network (TGN)/endosomal dynamics in yeast. Paradoxically, combinatorial depletion of Sec14 and Tlg2 activities elicits trafficking defects from the endoplasmic reticulum, and these defects are accompanied by compromise of the unfolded protein response (UPR). UPR failure occurs downstream of Hac1 mRNA splicing, and it is further accompanied by defects in TOR signaling. The data link TGN/endosomal dynamics with ceramide homeostasis, UPR activity, and TOR signaling in yeast, and they identify the Sit4 protein phosphatase as a primary conduit through which ceramides link to the UPR. We suggest combinatorial Sec14/Tlg2 dysfunction evokes inappropriate turnover of complex sphingolipids in endosomes. One result of this turnover is potentiation of ceramide-activated phosphatase-mediated down-regulation of the UPR. These results provide new insight into Sec14 function, and they emphasize the TGN/endosomal system as a central hub for homeostatic regulation in eukaryotes.
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PMID:Trans-Golgi network and endosome dynamics connect ceramide homeostasis with regulation of the unfolded protein response and TOR signaling in yeast. 1875 6

Following organ transplantation many patients suffer from drug-related side effects, or receive more immunosuppression than necessary to prevent rejection. Hence, parameters are needed to tailor the immunosuppressive therapy to the individual needs of an organ recipient. The aim of this study was to determine whether drug combinations provoke specific gene expression patterns in a simple assay system in vitro. Stimulated peripheral blood lymphocytes were cultured in the presence of cyclosporine A, tacrolimus, mycophenolic acid, everolimus and sirolimus, or combinations thereof. Using a cDNA microarray, we found that all samples clustered in drug-specific groups. Gene expression profiles were almost identical in PBL treated with either cyclosporine A or tacrolimus, and with either sirolimus or everolimus. More than 50 genes were synergistically affected by combinations of calcineurin-inhibitors and TOR-inhibitors and drug-specific regulated genes could be identified for both substance groups. Our data suggest that in vitro gene profiling can be used to describe synergistic effects of immunosuppressive drugs. Furthermore, our approach may help to identify marker genes urgently needed to optimize and individualize immunosuppressive drug regimens after organ transplantation.
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PMID:Combination of immunosuppressive drugs leaves specific "fingerprint" on gene expression in vitro. 1923 37

Yeast ptc1 mutants are rapamycin and caffeine sensitive, suggesting a functional connection between Ptc1 and the TOR pathway that is not shared by most members of the type 2C phosphatase family. Genome-wide profiling revealed that the ptc1 mutation largely attenuates the transcriptional response to rapamycin. The lack of Ptc1 significantly prevents the nuclear translocation of Gln3 and Msn2 transcription factors to the nucleus, as well as the dephosphorylation of the Npr1 kinase, in response to rapamycin. This could explain the observed decrease in both the basal and rapamycin-induced expression of several genes subjected to nitrogen catabolite repression (GAT1, MEP1, and GLN1) and stress response element (STRE)-driven promoters. Interestingly, this decrease is abolished in the absence of the Sit4 phosphatase. Epitasis analysis indicates that the mutation of SIT4 or TIP41, encoding a Tap42-interacting protein, abolishes the sensitivity of the ptc1 strain to rapamycin and caffeine. All of these results suggest that Ptc1 is required for normal TOR signaling, possibly by regulating a step upstream of Sit4 function. According to this hypothesis, we observe that the mutation of PTC1 drastically diminishes the rapamycin-induced interaction between Tap42 and Tip41, and this can be explained by lower-than-normal levels of Tip41 in ptc1 cells. Ptc1 is not necessary for the normal expression of the TIP41 gene; instead, its absence dramatically affects the stability of Tip41. The lack of Ptc1 partially abolishes the rapamycin-induced dephosphorylation of Tip41, which may further decrease Tap42 binding. Reduced Tip41 levels contribute to the ptc1 phenotypes, although additional Ptc1 targets must exist. All of these results provide the first evidence showing that a type 2C protein phosphatase is required for the normal functioning of the TOR pathway.
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PMID:Normal function of the yeast TOR pathway requires the type 2C protein phosphatase Ptc1. 1927 91


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