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)

Protein phosphatases 1 and 2A (PP1 and PP2A) were identified in a variety of plant cells and found to be particulate or soluble depending on the species. In extracts prepared from oilseed-rape seeds these enzymes were associated with microsomes and more rapidly sedimenting fractions, whereas in wheat leaf extracts they were largely microsomal, the remainder being present in the soluble fraction. In pea leaf and carrot cell extracts PP1 and PP2A were almost entirely soluble. No PP1 or PP2A activity was associated with the membranes or stroma of chloroplasts in oilseed-rape seeds, pea leaves and wheat leaves. An Mg2(+)-dependent okadaic acid-insensitive protein phosphatase that resembles protein phosphatase 2C (PP2C) was detected in carrot cells, pea leaves and wheat leaves, but not in oilseed-rape seeds. In wheat leaf extracts PP2C was mostly present in the soluble fraction, a different location from PP1 or PP2A. The rapid inactivation of the cytosolic enzyme quinate dehydrogenase (QDH) in a fraction prepared from light-grown carrot cells was completely blocked by either okadaic acid or microcystin (two potent and specific inhibitors of PP1 and PP2A), whereas inhibitor 2 (a specific inhibitor of PP1) inhibited inactivation by only about 10%. Addition of the purified PP2A catalytic subunit from mammalian skeletal muscle increased the rate of QDH inactivation, whereas addition of mammalian PP1 did not. It is concluded that PP2A is the major enzyme responsible for dephosphorylating (inactivating) QDH in carrot cells. These observations indicate that okadaic acid and microcystin may be useful for identifying other plant processes that are controlled by phosphorylation/dephosphorylation mechanisms. Okadaic acid did not prevent the rapid inactivation of phosphoribulokinase or activation of glucose-6-phosphate dehydrogenase in a fraction prepared from light-grown pea leaves, and addition of the purified catalytic subunits of PP1 and PP2A did not accelerate either process. These observations, in conjunction with the absence of PP1 and PP2A activity in chloroplasts, suggest that these phosphatases are not involved in the regulation of chloroplast metabolism.
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PMID:Plant protein phosphatases. Subcellular distribution, detection of protein phosphatase 2C and identification of protein phosphatase 2A as the major quinate dehydrogenase phosphatase. 184 22

FK506 inhibits the Ca2+/calmodulin-dependent protein phosphatase calcineurin, which plays a critical role in yeast subjected to salt stress. A chemical genetic screen for small molecules that suppress growth inhibition by high NaCl plus FK506 identified a structurally related class of suppressors of FK506 (SFKs) named SFKs 2-4. To identify possible protein targets for these small molecules, a genome-wide screen of approximately 4,700 haploid yeast deletion strains was undertaken for strains showing resistance to high NaCl plus FK506. This screen yielded a number of genes not previously implicated in salt stress, including ALD6, which encodes an NADP(+)-dependent aldehyde dehydrogenase, and UTR1, which encodes an NAD+ kinase. Transcriptional profiling of yeast treated with SFK2 indicated that the SFKs target the Ald6p pathway. In addition, screening of the deletion strains for hypersensitivity to SFK2 yielded ZWF1, encoding glucose-6-phosphate dehydrogenase, which has been shown to play an overlapping role with Ald6p in NADPH production. Furthermore, the SFKs inhibited the activity of Ald6p in vitro. Having established that the SFKs target Ald6p, they were used as tools to implicate systematically other gene products in the Ald6p pathway, including Utr1p, which may function by supplying Ald6p with its NADP+ cofactor. Furthermore, growth improvement by the SFKs on high NaCl plus FK506 was shown to require GPD1, which encodes an NADH-dependent glycerol-3-phosphate dehydrogenase that is important for the production of glycerol in response to osmotic stress.
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PMID:Identification of Ald6p as the target of a class of small-molecule suppressors of FK506 and their use in network dissection. 1514 68

We investigated the interaction of MR with cAMP-response element binding protein (CREB) and provide a mechanistic explanation and insights into the cellular relevance. MR --> CREB crosstalk was assessed in vascular smooth muscle cells and heterologous expression systems. Experiments were designed in a way that only one variable changed at a time and the respective vehicles served as controls. MR, but not GR, activation (aldosterone or hydrocortisone, IC(50), approximately 0.3 nM) inhibits CREB transcriptional activity induced by stimulation of beta1/2-adrenoceptors and adenylyl cyclase or addition of membrane-permeable cAMP up to 70% within 2 h after addition. The MR DNA-binding domain is not required for this inhibition. cAMP formation is virtually unchanged, whereas MR exerts a robust inhibition of CREB(S133) phosphorylation via calcineurin/PP2B activation without changes in PP2B-Aalpha or beta expression. In parallel, the PP2B-sensitive NFaT-pathway is activated. The inhibitory crosstalk attenuates CREB-induced glucose-6-phosphate dehydrogenase expression. Overall, transcriptional relevant MR --> CREB crosstalk occurs at the level of CREB phosphorylation by enhanced calcineurin activity, enables GRE-independent genomic signaling of MR, and is of potential pathophysiological relevance.
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PMID:Mineralocorticoid receptor inhibits CREB signaling by calcineurin activation. 2010 17

Carbohydrate response element binding protein (ChREBP) is a Mondo family transcription factor that activates a number of glycolytic and lipogenic genes in response to glucose stimulation. We have previously reported that high glucose can activate the transcriptional activity of ChREBP independent of the protein phosphatase 2A (PP2A)-mediated increase in nuclear entry and DNA binding. Here, we found that formation of glucose-6-phosphate (G-6-P) is essential for glucose activation of ChREBP. The glucose response of GAL4-ChREBP is attenuated by D-mannoheptulose, a potent hexokinase inhibitor, as well as over-expression of glucose-6-phosphatase (G6Pase); kinetics of activation of GAL4-ChREBP can be modified by exogenously expressed GCK. Further metabolism of G-6-P through the two major glucose metabolic pathways, glycolysis and pentose-phosphate pathway, is not required for activation of ChREBP; over-expression of glucose-6-phosphate dehydrogenase (G6PD) diminishes, whereas RNAi knockdown of the enzyme enhances, the glucose response of GAL4-ChREBP, respectively. Moreover, the glucose analogue 2-deoxyglucose (2-DG), which is phosphorylated by hexokinase, but not further metabolized, effectively upregulates the transcription activity of ChREBP. In addition, over-expression of phosphofructokinase (PFK) 1 and 2, synergistically diminishes the glucose response of GAL4-ChREBP. These multiple lines of evidence support the conclusion that G-6-P mediates the activation of ChREBP.
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PMID:Glucose-6-phosphate mediates activation of the carbohydrate responsive binding protein (ChREBP). 2038 27