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

Saccharomyces cerevisiae mutants which exhibit phenotypes (calcium resistance and vanadate sensitivity) similar to those of calcineurin-deficient mutants were isolated. The mutants were classified into four complementation groups (crv1,2,3 and 4). Crv1 was allelic to cnb1, a mutation in the regulatory subunit of calcineurin. The nucleotide sequences of CRV2 and CRV3 genes which complemented the crv2 and crv3 mutations, respectively, are identical to those of BCK1/SLK1/SKC1/SSP31 and MPK1/SLT2, respectively, which are both involved in the MAP kinase cascade. A calcineurin-deletion mutation (delta cnb1), which by itself has no detectable effect on growth and morphology, enhanced some phenotypes (slow growth and morphological abnormality) of crv2 and crv3 mutants. These phenotypes of crv2 and crv3 mutants were partially suppressed by Ca2+ or by overproduction of the calcineurin subunits (Cmp2 and Cnb1). Like the calcineurin-deficient mutant, crv2 and crv3 mutants were defective in recovery from alpha-factor-induced growth arrest. The defect in recovery of the delta cnb1 mutant was suppressed by overexpression of MPK1. These results indicated that the calcineurin-mediated and the Mpk1- (Bck1-) mediated signaling pathways act in parallel to regulate functionally redundant cellular events important for growth.
Mol Gen Genet 1996 May 23
PMID:Genetic evidence for the functional redundancy of the calcineurin- and Mpk1-mediated pathways in the regulation of cellular events important for growth in Saccharomyces cerevisiae. 866 32

This paper describes characteristics of the transport of oxalate across the human erythrocyte membrane. Treatment of cells with low concentrations of H2DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonate) inhibits Cl(-)-Cl- and oxalate-oxalate exchange to the same extent, suggesting that band 3 is the major transport pathway for oxalate. The kinetics of oxalate and Cl- self-exchange fluxes indicate that the two ions compete for a common transport site; the apparent Cl- affinity is two to three times higher than that of oxalate. The net exchange of oxalate for Cl-, in either direction, is accompanied by a flux of H+ with oxalate, as is also true of net Cl(-)-SO4(2-) exchange. The transport of oxalate, however, is much faster than that of SO4(2-) or other divalent anions. Oxalate influx into Cl(-)-containing cells has an extracellular pH optimum of approximately 5.5 at 0 degrees C. At extracellular pH below 5.5 (neutral intracellular pH), net Cl(-)-oxalate exchange is nearly as fast as Cl(-)-Cl- exchange. The rapid Cl(-)-oxalate exchange at acid extracellular pH is not likely to be a consequence of Cl- exchange for monovalent oxalate (HOOC-COO-; pKa = 4.2) because monocarboxylates of similar structure exchange for Cl- much more slowly than does oxalate. The activation energy of Cl(-)-oxalate exchange is about 35 kCal/mol at temperatures between 0 and 15 degrees C; the rapid oxalate influx is therefore not a consequence of a low activation energy. The protein phosphatase inhibitor okadaic acid has no detectable effect on oxalate self-exchange, in contrast to a recent finding in another laboratory (Baggio, B., L. Bordin, G. Clari, G. Gambaro, and V. Moret. 1993. Biochim. Biophys. Acta. 1148:157-160.); our data provide no evidence for physiological regulation of anion exchange in red cells.
J Gen Physiol 1996 Jan
PMID:Characterization of oxalate transport by the human erythrocyte band 3 protein. 874 36

We previously showed (Frace, A.M. and H.C. Hartzell. 1993. Journal of Physiology. 472:305-326) that internal perfusion of frog atrial myocytes with the nonselective protein phosphatase inhibitors microcystin or okadaic acid produced an increase in the L-type Ca current (ICa) and a decrease in the delayed rectifier K current (IK). We hypothesized that microcystin revealed the activity of a protein kinase (PKX) that was basally active in the cardiac myocyte that could phosphorylate the Ca and K channels or regulators of the channels. The present studies were aimed at determining the nature of PKX and its phosphorylation target. The effect of internal perfusion with microcystin on ICa or IK was not attenuated by inhibitors of protein kinase A (PKA). However, the effect of microcystin on ICa was largely blocked by the nonselective protein kinase inhibitors staurosporine (10-30 nM), K252a (250 nM), and H-7 (10 microM). Staurosporine and H-7 also decreased the stimulation of ICa by isoproterenol, but K252a was more selective and blocked the ability of microcystin to stimulate ICa without significantly reducing isoproterenol-stimulated current. Internal perfusion with selective inhibitors of protein kinase C (PKC), including the autoinhibitory pseudosubstrate PKC peptide (PKC(19-31)) and a myristoylated derivative of this peptide had no effect. External application of several PKC inhibitors had negative side effects that prevented their use as selective PKC inhibitors. Nevertheless, we conclude that PKX is not PKC. PKA and PKX phosphorylate sites with different sensitivities to the phosphatase inhibitors calyculin A and microcystin. In contrast to the results with ICa, the effect of microcystin on IK was not blocked by any of the kinase inhibitors tested, suggesting that the effect of microcystin on IK may not be mediated by a protein kinase but may be due to a direct effect of microcystin on the IK channel.
J Gen Physiol 1995 Sep
PMID:Effects of protein phosphatase and kinase inhibitors on the cardiac L-type Ca current suggest two sites are phosphorylated by protein kinase A and another protein kinase. 878 40

NSP5 (non-structural protein 5) is one of two proteins encoded by genome segment 11 of group A rotaviruses. In virus-infected cells NSP5 accumulates in the virosomes and is found as two polypeptides with molecular masses of 26 and 28 kDa (26K and 28K proteins). NSP5 has been previously shown to be post-translationally modified by the addition of O-linked monosaccharide residues of N-acetylglucosamine and also by phosphorylation. We have now found that, as a consequence of phosphorylation, a complex modification process gives rise to previously unidentified forms of NSP5, with molecular masses of up to 34 kDa. Treatment with phosphatases of NSP5 obtained from virus-infected cells produced a single band of 26 kDa. NSP5 could be phosphorylated in vitro by incubation of immunoprecipitates with [gamma-32P]ATP, producing mainly phosphorylated products of 28 and 32-34 kDa (32-34K). In both in vivo and in vitro phosphorylated NSP5, phosphates were only found attached via serine and threonine residues. The in vitro translated NSP5 precursor polypeptide, molecular mass 25 kDa (25K), could also be phosphorylated and transformed into a 28K protein by incubation with extracts obtained from virus-infected cells, but not from non-infected cells. In addition, NSP5 labelled in vivo with [1,6-3H]glucosamine showed mainly the presence of the 26K and 28K proteins (converted to 26K by protein phosphatase treatment) suggesting that the type of protein produced is regulated according to the level of phosphorylation and/or O-glycosylation. The results also suggest that NSP5 is autophosphorylated.
J Gen Virol 1996 Sep
PMID:Phosphorylation generates different forms of rotavirus NSP5. 881 Oct 3

Hexokinase 2 from Saccharomyces cerevisiae is phosphorylated in vivo at serine-15 [Kriegel et al. (1994) Biochemistry 33, 148-152] and undergoes ATP-dependent autophosphorylation-inactivation in vitro when incubated in the presence of D-xylose [Fernandez et al. (1988) J. Gen. Microbiol. 134, 2493-2498]. This study identifies the site of inactivation by autophosphorylation as serine-158 by observation of a single tryptic peptide difference, peptide sequencing, and size determination by mass spectrometry. Mutation of serine-158 to alanine and cysteine, respectively, prevents autophosphorylation and causes a drastic decrease of the catalytic activity while mutational change to glutamate results in a complete loss of enzyme activity. The catalytically active mutant enzymes display an increased affinity for glucose and exhibit higher K(M) with respect to MgATP. Phosphoserine/phosphothreonine-specific protein phosphatase-2A completely reverses the autophosphorylative inactivation of the wild-type enzyme.
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PMID:Autophosphorylation-inactivation site of hexokinase 2 in Saccharomyces cerevisiae. 904 92

Protein phosphorylation is a primary means of mediating signal transduction events that control cellular processes. Accordingly, the activities of protein kinases and phosphatases are highly regulated. One level of regulation is that the subcellular distribution of several kinases and phosphatases is restricted by association with targeting proteins or subunits. This mechanism promotes rapid and preferential modulation of specific targets within a defined microenvironment in response to diffusible second messengers. The type II cAMP-dependent protein kinase (PKA) is targeted by association of its regulatory subunit (RII) with A-kinase anchoring proteins (AKAPs). To date, 36 unique AKAPs have been identified. Each of these proteins contains a conserved amphipathic helix responsible for AKAP association with cellular structures. Disruption of PKA/AKAP interaction with peptides patterned after the amphipathic helix region blocks certain cAMP responses, including the modulation of glutamate receptor ion-channel activity in neurons and transcription of cAMP-responsive genes. Yeast two-hybrid screening methods have identified neuronal specific AKAP79-binding proteins including the beta isoform of the phosphatase 2B, calcineurin. Biochemical and immunological studies have confirmed the two-hybrid results and identified additional members of this multienzyme signaling complex, including certain protein kinase C isoforms. These findings are consistent with colocalization of CaN, PKC, and type II PKA by AKAP79 and suggest a novel model for reversible phosphorylation in which the opposing kinase and phosphatase actions are colocalized in a signal transduction complex by association with a common anchor protein.
Soc Gen Physiol Ser 1997
PMID:Dissection of protein kinase and phosphatase targeting interactions. 921 Feb 33

Modulation of L-type Ca2+ channels by tonic elevation of cytoplasmic Ca2+ was investigated in intact cells and inside-out patches from human umbilical vein smooth muscle. Ba2+ was used as charge carrier, and run down of Ca2+ channel activity in inside-out patches was prevented with calpastatin plus ATP. Increasing cytoplasmic Ca2+ in intact cells by elevation of extracellular Ca2+ in the presence of the ionophore A23187 inhibited the activity of L-type Ca2+ channels in cell-attached patches. Measurement of the actual level of intracellular free Ca2+ with fura-2 revealed a 50% inhibitory concentration (IC50) of 260 nM and a Hill coefficient close to 4 for Ca2+- dependent inhibition. Ca2+-induced inhibition of Ca2+ channel activity in intact cells was due to a reduction of channel open probability and availability. Ca2+-induced inhibition was not affected by the protein kinase inhibitor H-7 (10 microM) or the cytoskeleton disruptive agent cytochalasin B (20 microM), but prevented by cyclosporin A (1 microg/ ml), an inhibitor of protein phosphatase 2B (calcineurin). Elevation of Ca2+ at the cytoplasmic side of inside-out patches inhibited Ca2+ channels with an IC50 of 2 microM and a Hill coefficient close to unity. Direct Ca2+-dependent inhibition in cell-free patches was due to a reduction of open probability, whereas availability was barely affected. Application of purified protein phosphatase 2B (12 U/ml) to the cytoplasmic side of inside-out patches at a free Ca2+ concentration of 1 microM inhibited Ca2+ channel open probability and availability. Elevation of cytoplasmic Ca2+ in the presence of PP2B, suppressed channel activity in inside-out patches with an IC50 of approximately 380 nM and a Hill coefficient of approximately 3; i.e., characteristics reminiscent of the Ca2+ sensitivity of Ca2+ channels in intact cells. Our results suggest that L-type Ca2+ channels of smooth muscle are controlled by two Ca2+-dependent negative feedback mechanisms. These mechanisms are based on (a) a protein phosphatase 2B-mediated dephosphorylation process, and (b) the interaction of intracellular Ca2+ with a single membrane-associated site that may reside on the channel protein itself.
J Gen Physiol 1997 Nov
PMID:Intracellular Ca2+ inhibits smooth muscle L-type Ca2+ channels by activation of protein phosphatase type 2B and by direct interaction with the channel. 934 23

The function of Neurospora crassa calcineurin was investigated in N. crassa strains transformed with a construct that provides for the inducible expression of antisense RNA for the catalytic subunit of calcineurin (cna-1). Induction of antisense RNA expression was associated with reduced levels of cna-1 mRNA and of immunodetectable CNA1 protein and decreased calcineurin enzyme activity, indicating that a conditional reduction of the target function had been achieved in antisense transformants with multiple construct integrations. Induction conditions caused growth arrest which indicated that the cna-1 gene is essential for growth of N. crassa. Growth arrest was preceded by an increase in hyphal branching, changes in hyphal morphology and concomitant loss of the distinctive tip-high Ca2+ gradient typical for growing wild-type hyphae. This demonstrates a novel and specific role for calcineurin in the precise regulation of apical growth, a common form of cellular proliferation. In vitro inhibition of N. crassa calcineurin by the complex of cyclosporin A (CsA) and cyclophilin20, and increased sensitivity of the induced transformants to the calcineurin-specific drugs CsA and FK506 imply that the drugs act in N. crassa, as in T-cells and Saccharomyces cerevisiae, by inactivating calcineurin. The finding that exposure of growing wild-type mycelium to these drugs leads to a phenotype very similar to that of the cna-1 antisense mutants is consistent with this idea.
Mol Gen Genet 1997 Sep
PMID:Impairment of calcineurin function in Neurospora crassa reveals its essential role in hyphal growth, morphology and maintenance of the apical Ca2+ gradient. 934 1

The Saccharomyces cerevisiae crv mutants (crv1, 2, 3 and 4) exhibit phenotypes, such as calcium resistance and vanadate sensitivity, which are apparently similar to those of calcineurin-deficient mutants. We have cloned and characterized the CRV4 gene that complements all the phenotypes of the crv4 mutant. DNA sequencing revealed that CRV4 is identical to the previously cloned gene TTP1, which encodes a type II membrane protein of unknown function. Deletion of CRV4/TTP1 causes no obvious phenotype except for Ca2+ resistance and vanadate sensitivity, but is synthetically lethal in combination with a deletion of MPK1, in a manner which is suppressible by the addition of an osmotic stabilizer. In medium containing sorbitol as an osmotic stabilizer, the enb1 mpk1 ttp1 triple mutant exhibits a more severe growth defect than does any of the double mutants enb1 ttp1, enb1 mpk1 or mpk1 ttp1. A high Ca2+ concentration (50 mM) or a constitutively active form of calcineurin partially suppresses the growth defect of the mpk1 ttp1 double mutant. These results indicate that Ttp1 participates in a cellular event essential for growth and morphogenesis, in parallel with the pathways involving Mpk1 MAP kinase and calcineurin.
Mol Gen Genet 1997 Nov
PMID:Yeast Crv4/Ttp1, a predicted type II membrane protein, is involved in an event important for growth, functionally overlapping with the event regulated by calcineurin- and Mpk1-mediated pathways. 941 31

1. An inward current (I[in]) was produced by gamma-aminobutyric acid (GABA) and muscimol, but not by baclofen, in an identifiable giant neuron type, v-LCDN (ventral-left cerebral distinct neuron), of an African giant snail (Achatina fulica Ferussac) under voltage clamp. 2. The pharmacological features of the excitatory GABA receptors in this Achatina neuron type, termed the Achatina muscimol II type GABA receptors, were mainly comparable to those of the mammalian GABA(C) receptors. 3. It was demonstrated in the present study that the following inhibitors for intracellular signal transduction systems showed no significant effect on the I(in) produced by GABA in this Achatina neuron type: H-7 [1-(5-isoquinolinyl sulfonyl)-2-methylpiperazine], an inhibitor of cyclic AMP-dependent protein kinase (PKA), cyclic GMP-dependent protein kinase (PKG) and protein kinase C (PKC); H-8 (N-[2-(methylamino)-ethyl]-5-isoquinolinesulfonamide), a PKA and PKG inhibitor; H-9 [N-(2-aminoethyl)-5-isoquinolinesulfonamide], a PKA inhibitor; staurosporine ((9alpha,10beta,11beta,13alpha)-(+)-2,3,10,11,12 ,13-hexahydro-10-methoxy-9-methyl-11-(methylamino)-9,13-epoxy-1H,9H-d iindolo[1,2,3-gh: 3',2',1'-1m]pyrrolo[3,4-j] [1,7]benzodiazonin-1-one), a PKA and PKC inhibitor; KT5823 ((8R,9S, 11S)-9-methoxy-9-methoxycarbonyl-2N,8-dimethyl-2,3,9,10-tetrahydro-8,11- epoxy-1H,8H,11H-2,7b,11a-triazadibenzo[a,g]cycloocta[c,d,e]- trinden-1-one), a PKG inhibitor; W-7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], a calmodulin inhibitor; ML-9 [1-(5-chloronaphthalene-1-sulfonyl-1H-hexahydro-1,4-diazepine hydrochloride], a myosin light-chain kinase inhibitor; genistein [5,7-dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one], a tyrosine protein kinase inhibitor; IBMX (3-isobutyl-1-methylxanthine), a cyclic nucleotide phosphodiesterase (PDE) inhibitor; fluphenazine nitrogen-mustard (2-chloroethyl)-4[3-(2-trifluoromethyl-10-phenothiazinyl)-propyl]p iperazine dihydrochloride), a calmodulin-dependent PDE inhibitor; calyculin A, a type 1 protein phosphatase inhibitor; and okadaic acid (9,10-deepithio-9,10-didehydroacanthifolicin), a type 1, 2A and 2B protein phosphatase inhibitor. 4. With these results, it was proposed that the excitatory Achatina muscimol II type GABA receptors in v-LCDN are not metabotropic but ionotropic.
Gen Pharmacol 1998 Feb
PMID:Effects of inhibitors for intracellular signal transduction systems on the inward current produced by GABA in a snail neuron. 950 77


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