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)

The expression of a regulatory subunit of calcineurin (CaN beta) during rat spermatogenesis was examined in rat testes using a monoclonal antibody Va1. Results showed that a testis-specific isoform of CaN beta was expressed only 3 weeks after birth, when meiosis begins, and increased in amount depending on the maturation of spermatogenesis. The matured sperm, which consists of only post-meiotic cells, is most likely to have only the testis-specific isoform of CaN beta. The brain type isoform of CaN beta was not detected in rat sperm. Immunoblot analysis of testes from different rodent species by a monoclonal antibody Va1 showed that all rodent species examined had their own homologues corresponding to a testis-specific isoform of CaN beta in rats, although they showed distinctively different molecular weights on SDS-PAGE compared to the testis-specific isoform in rats. Each homologue was shown to be specifically expressed in post-meiotic phase of spermatogenesis, as was seen in rats.
Biochem Biophys Res Commun 1992 Sep 16
PMID:The evidence for post-meiotic expression of a testis-specific isoform of a regulatory subunit of calcineurin using a monoclonal antibody. 132 57

The present study describes the ability of 315 nM okadaic acid to induce melanosome dispersion in cultured Xenopus laevis melanophores. This effect of okadaic acid is similar to that of a-melanocyte stimulating hormone (MSH) and can be reversed by melatonin treatment; it indicates that a member of the protein-phosphatase 1 or 2A families must be active for maintenance of the aggregated state. Higher concentrations of okadaic acid (1 microM) attenuate the response of Xenopus melanophores to melatonin leading to the hypothesis that melatonin action is mediated by the calcium/calmodulin activated phosphatase 2B. This hypothesis seems unlikely, however, since the calcium/calmodulin inhibitors TFP and W7 do not prevent melatonin-induced pigment aggregation, but instead induce aggregation on their own.
Pigment Cell Res 1992 Sep
PMID:The protein-phosphatase inhibitor okadaic acid mimics MSH-induced and melatonin-reversible melanosome dispersion in Xenopus laevis melanophores. 132 76

An endogenous protein which inhibits protein kinase C (PKC)-mediated effects has been detected in rat heart ventricular tissue. This functional PKC-inhibitory activity was completely abolished by okadaic acid, making it possible to measure PKC activity in non-purified cell fractions. This suggests that the PKC-inhibitory activity is a type 1 or 2A serine/threonine phosphatase. Confirming this, membrane and cytosolic PKC-inhibitory preparations were found to contain phosphatase activity which was suppressed by okadaic acid, exhibiting an IC50 (concn. required for 50% inhibition) of 1.5-2 nM. Furthermore, okadaic acid stimulated prostacyclin production in rat cardiomyocytes and aortic smooth-muscle cells and, like the PKC activator phorbol 12-myristate 13-acetate, it augmented the prostacyclin formation induced by the Ca2+ ionophore A23187. Our results strongly suggest that the endogenous PKC 'inhibitor' is the cellular phosphatase 2A, which plays an important role in regulating the phosphorylation level of PKC target proteins.
Biochem J 1992 Sep 15
PMID:Functional inhibition of protein kinase C-mediated effects in myocardial tissue is due to the phosphatase 2A. 132 18

Cytokines such as interleukin-1, which are found in the brain after trauma, regulate expression of nerve growth factor (NGF) mRNA and protein in hippocampal cultures. We have investigated possible mechanisms by which Il-1 beta regulates NGF in hippocampal cells. The induction of NGF mRNA by Il-1 beta was blocked by a receptor antagonist indicating that this effect is receptor mediated. Il-1 beta elicited a dramatic induction of c-fos mRNA and a slight elevation of c-jun mRNA in a time dependent manner which may allow for a role in the induction of NGF mRNA expression. We examined whether specific second messenger pathways were involved in mediating the action of Il-1 beta in the hippocampus. Activation of cAMP with forskolin or treatment with 8-Br-cAMP had no effect on NGF mRNA levels. Moreover, exposure of hippocampal cultures to Il-1 beta evoked no change in cAMP levels, indicating that this second messenger system played little or no role in the regulation of NGF expression by Il-1 beta in these cells. Further, interleukin-1 elicited no change in membrane inositol phosphate turnover, nor did it affect intracellular calcium levels. Treatment of cell cultures with the phorbol ester PMA elicited an increase in NGF mRNA, suggesting that activation of protein kinase C (PKC) may mediate NGF mRNA expression. However, prolonged treatment of cultures with PMA to desensitize PKC did not eliminate the Il-1 beta induction of NGF mRNA. Il-1 beta, therefore, did not appear to activate NGF expression via cAMP, Ca2+, or a PKC isoform that is downregulated by prolonged PMA treatment. However, a phosphorylation event may be involved in the signal transduction mechanism, as treatment with okadaic acid to inhibit protein phosphatase 2a potentiated the induction of NGF mRNA by Il-1 beta. The results presented indicate that Il-1 beta acts via its receptor to induce a rise in NGF expression. Identification of the specific second messenger pathway has remained elusive; however, a phosphorylation event appears to be intermediary. Moreover, the induction of c-fos and c-jun may represent a final common path in activation of NGF gene expression by different signals such as Il-1 beta and PMA.
J Neurosci Res 1992 Sep
PMID:Mechanisms of nerve growth factor mRNA regulation by interleukin-1 beta in hippocampal cultures: role of second messengers. 133 37

We have used a monoclonal antibody (MAb E12), one of several such antibodies raised against theophylline-treated Necturus gallbladder epithelial cells, to isolate a chloride channel protein by the use of an immunoaffinity column and FPLC. This protein (M(r) 219,000) has been reconstituted into a planar lipid bilayer, where it behaves as a chloride-selective channel (PCl/PNa = 20.2; PNa/PK = 1) whose unit conductance is 62.4 +/- 4.6 pS. Antibody added to the trans side (there is no effect from the cis side) causes channel open probability to drop to virtually zero, but has no effect on the conductance or the selectivity of single channels. To test the role of phosphorylation in the activity of the native channel, we studied the effects of the protein phosphatase inhibitor okadaic acid (OA) on intact gallbladders, and showed that channels opened by theophylline treatment and closed by antibody are reopened reversibly by OA (0.01-1.0 microM). Addition of the catalytic subunit of protein phosphatase 2A (PP-2A) to the cis side of a bilayer containing reconstituted chloride channels caused closure of the channels after a delay, and subsequent addition of ATP and the catalytic subunit of cAMP-dependent protein kinase (PKA) caused immediate reopening. These data indicate that (a) this chloride channel protein inserts in a directed way into the bilayer such that the cis side is 'intracellular', (b) the purified channel protein is phosphorylated, and (c) gating from the cellular side is controlled by the direct phosphorylation and dephosphorylation of the channel protein.
Mol Cell Biochem 1992 Sep 08
PMID:Reconstitution and regulation of an epithelial chloride channel. 133 26

Calcineurin, an intracellular protein phosphatase (type 2B), is reported to inhibit L-type (slow) calcium channels and thereby play a key role in channel inactivation. The present study was undertaken to examine effects of calcineurin on slow channel dependent action potentials of 3-days-old embryonic chick ventricle and to assess the role of this enzyme in regulation of developing slow channels. Calcineurin trapped in phosphatidylcholine-liposomes to facilitate its intracellular uptake was found to inhibit maximal upstroke velocity (+Vmax), overshoot and duration of action potentials. At higher doses of calcineurin containing liposomes the preparations ceased to exhibit spontaneous activity but elicited electrically driven action potentials with lower +Vmax and overshoot. These observations show that calcineurin down-modulates the embryonic cardiac slow channels under basal conditions.
J Dev Physiol 1992 Sep
PMID:Calcineurin trapped in liposomes inhibits the action potentials of isolated 3-days-old embryonic chick ventricle. 133 32

Based on recent X-ray structural information, six site-directed mutants of human cyclophilin A (hCyPA) involving residues in the putative active site--H54, R55, F60, Q111, F113, and H126--have been constructed, overexpressed, and purified from Escherichia coli to homogeneity. The proteins W121A (Liu, J., Chen, C.-M., & Walsh, C.T., 1991a, Biochemistry 30, 2306-2310), H54Q, R55A, F60A, Q111A, F113A, and H126Q were assayed for cis-trans peptidyl-prolyl isomerase (PPIase) activity, their ability to bind the immunosuppressive drug cyclosporin A (CsA), and protein phosphatase 2B (calcineurin) inhibition in the presence of CsA. Results indicate that H54Q, Q111A, F113A, and W121A retain 3-15% of the catalytic efficiency (kcat/Km) of wild-type recombinant hCyPA. The remaining three mutants (R55A, F60A, and H126Q) each retain less than 1% of the wild-type catalytic efficiency, indicating participation by these residues in PPIase catalysis. Each of the mutants bound to a CsA affinity matrix. The mutants R55A, F60A, F113A, and H126Q inhibited calcineurin in the presence of CsA, whereas W121A did not. Although CsA is a competitive inhibitor of PPIase activity, it can complex with enzymatically inactive cyclophilins and inhibit the phosphatase activity of calcineurin.
Protein Sci 1992 Sep
PMID:Active site mutants of human cyclophilin A separate peptidyl-prolyl isomerase activity from cyclosporin A binding and calcineurin inhibition. 133 79

The distribution of inhibitor-1, a cyclic AMP-regulated inhibitor of protein phosphatase-1, was analyzed in various brain regions and peripheral tissues of various species by immunolabeling of sodium dodecyl sulfate-poly-acrylamide gel transfers using specific antibodies. The distribution of inhibitor-1 was directly compared to that of DARPP-32, a structurally related cyclic AMP-regulated inhibitor of protein phosphatase-1. In rat CNS, a single immunoreactive protein of M(r) 30,000, identified as inhibitor-1, was widely distributed. In contrast, DARPP-32 was highly concentrated in the basal ganglia. Inhibitor-1 was detected in brain tissue from frog (M(r) 27,000), turtle (M(r) 29,000/33,000), canary (M(r) 26,000), pigeon (M(r) 28,000), mouse (M(r) 30,500), rabbit (M(r) 26,500), cow (M(r) 27,000), and monkey (M(r) 27,500), but not from goldfish. Inhibitor-1 was detected at various levels in most peripheral tissues of the species studied; however, it was not detectable in certain tissues of particular species (e.g., rat and cow liver). DARPP-32 was detected in brain tissue of all the species tested except frog and goldfish, but was not detectable in most peripheral tissues. Both inhibitor-1 and DARPP-32 were concentrated in the cytosol and synaptosomal cytosol of rat striatum. The developmental expressions of inhibitor-1 and DARPP-32 in rat striatum differed: the level of inhibitor-1 peaked in the first postnatal week and then declined by the third postnatal week, whereas the level of DARPP-32 increased to a peak level by the third postnatal week and remained elevated thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)
J Neurochem 1992 Sep
PMID:Distribution of protein phosphatase inhibitor-1 in brain and peripheral tissues of various species: comparison with DARPP-32. 135 88

1. The monoamine dopamine and the amino acid glutamate are major neurotransmitters in the basal ganglia implicated in the normal functions of the striatum and in extrapyramidal disease states. To study the effects of these neurotransmitters on gene transcription in striatal neurons, we treated rats with dopamine (monoamine) agonists and with glutamate agonists and monitored the induction of Fos-like protein in striatal neurons. We administered the indirect monoamine agonists cocaine and amphetamine intraperitoneally and gave the glutamate agonist quinolinic acid by direct intrastriatal injection. We identified the phenotypes of the responsive neurons by immunohistochemistry and by enzyme histochemistry in double staining protocols. 2. Both the indirect monoamine agonists and the glutamate receptor agonist stimulated rapid nuclear expression of Fos-like protein in specific classes of striatal neurons. The induction by cocaine and amphetamine was blocked by pretreatment with the dopamine D1-like receptor antagonist SCH23390, and the induction by quinolinic acid was blocked by pretreatment with MK-801, a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) glutamate receptor. 3. The monoamine and glutamate agonists both induced Fos-like protein exclusively in striatal neurons that constitutively expressed the protein phosphatase inhibitor DARPP-32 (dopamine and cAMP-regulated phosphoprotein). 4. The dopamine agonists failed to induce detectable Fos-like protein in striatal neurons expressing enkephalin, even though many such neurons expressed DARPP-32. By contrast, many enkephalinergic neurons did express Fos-like protein in response to glutamatergic stimulation. 5. Glutamate agonist stimulation, but not dopamine agonist stimulation, induced Fos-like protein in a subpopulation of striatal interneurons, namely, a group of neurons exhibiting NADPH-diaphorase activity. 6. These findings suggest that stimulation of dopamine D1-like receptors (or related monoamine receptors) and glutamate NMDA receptors activates neuron-specific programs of immediate-early gene expression in the striatum. Our findings further suggest that monoamine and glutamate may act cooperatively at the transcriptional level on a functionally defined subset of striatal neurons.
J Neurophysiol 1992 Sep
PMID:Dopamine and glutamate agonists stimulate neuron-specific expression of Fos-like protein in the striatum. 135 24

Human prostatic acid phosphatase (PAcP) is a tissue-specific differentiation antigen and is the major phosphotyrosyl (p-tyr) protein phosphatase in normal differentiated prostate epithelial cells. In prostate carcinomas, cellular PAcP has a low expression. We examined the expression of cellular PAcP activity and its correlation with cell growth that may lead us to understand the role of tyrosine phosphorylation in human prostate cells. LNCaP cells, which expressed the highest cellular PAcP activity, had the slowest growth rate and the lowest p-tyr level among three human prostate carcinoma cell lines: LNCaP, DU145, and PC-3. This inverse correlation was further examined in LNCaP cells, since these cells remain hormone-sensitive. Androgen, a classical stimulator of prostate cells, stimulated the growth of LNCaP cells while cellular PAcP activity decreased and p-tyr levels increased. This phenomenon was also observed when cells were treated with epidermal growth factor and fetal bovine serum. Both epidermal growth factor and fetal bovine serum stimulated the growth of LNCaP cells whereas cellular PAcP activity decreased. Furthermore, when cell growth was arrested at low temperatures (23 degrees C), cellular PAcP activity was elevated. To establish the relationship of cellular PAcP activity with cell growth rate, we transfected a complementary DNA encoding the full length PAcP protein into another human prostate carcinoma line, PC-3, that lacks endogenous PAcP. Two stable transfectants, designated PC-18 and PC-416 cells, were obtained and shown to express PAcP mRNA transcribed from the transfected complementary DNA. The expression of PAcP activity in PC-416 cells, but not PC-18 cells, was associated with a lower p-tyr level and a slower growth rate than control cells transfected with the expression vector alone. In conclusion, in LNCaP cells, the stimulated cell growth is associated with an increased p-tyr level and a decreased cellular PAcP activity. In PAcP complementary DNA-transfected PC-416 cells, the low level of p-tyr corresponds to a slow growth rate.
Cancer Res 1992 Sep 01
PMID:Expression of human prostatic acid phosphatase activity and the growth of prostate carcinoma cells. 138 Aug 86


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