Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previously we found that ethanol increases expression of the constitutive 70-kDa heat shock protein (Hsc70) in NG108-15 neuroblastoma x glioma cells. We suggested that known ethanol actions on cellular protein trafficking may relate to Hsc70 induction because Hsc70 functions as a molecular chaperone. Here we use a subtractive hybridization protocol to isolate ethanol-responsive genes (EtRGs). Northern blot hybridization verified ethanol-induced increases in mRNA abundance for five cDNA clones isolated from ethanol-treated NG108-15 neuroblastoma x glioma cells. DNA sequence analysis identified one EtRG as 94-kDa glucose-regulated protein (GRP94), a member of the "glucose-responsive" subgroup of stress proteins. Other identified EtRGs included an insulin-induced growth-response protein gene and an intracisternal A-type particle gene. Sequence analysis of the remaining two EtRGs showed no homology in DNA sequence databases. All EtRGs showed wide tissue expression, except SL64, which was not detected in Northern blot analyses of adult mouse or rat tissues. Ethanol also increased mRNA abundance for 78-kDa glucose-regulated protein (GRP78), a molecular chaperone known to function in glycoprotein trafficking and usually coordinately regulated with GRP94. However, ethanol induced GRP94 more than GRP78, a pattern distinct from those of other inducers of these genes. All EtRGs, including GRP94 and GRP78, showed similar ethanol concentration-dependent increases in mRNA abundance. In contrast, thapsigargin and other inducers of glucose-responsive proteins increased GRP94 and GRP78 mRNA levels without altering expression of other EtRGs. Our studies demonstrate that several molecular chaperones constitute a subset of EtRGs. Ethanol appears to regulate these EtRGs by a unique mechanism, rather than one shared by classical inducers of stress proteins.
Mol Pharmacol 1994 Nov
PMID:Ethanol-responsive genes in neural cells include the 78-kilodalton glucose-regulated protein (GRP78) and 94-kilodalton glucose-regulated protein (GRP94) molecular chaperones. 796 74

The kinetic parameters of almond beta-glucosidase (beta-D-glucoside glucohydrolase; EC 3.2.1.21), using pNGP as substrate were kM = 2.24 +/- 0.11 mM and Vmax 588 +/- 25.1 U/mg protein. Only Hg(II) and Cu(II) showed irreversible inactivation of the enzyme. However, when these metals were present in the reaction system the inhibition effects were consistent with a mixed-type inhibition pattern (Cu(II) ki: 5.08 mM and Hg(II) ki: 0.07 mM). The glucose kinetic effect was also consistent with a mixed-type inhibition (ki = 406 mM) pattern with pNGP as varied substrate. Ethanol displayed the kinetic pattern of competitive inhibition (ki = 640 mM).
Biochem Mol Biol Int 1994 Aug
PMID:Effects of glucose, ethanol, Hg(II) and Cu(II) on almond beta-glucosidase. 798 62

Ethanol appears to modulate the function of selective mammalian receptors and transporters by interacting with highly specific membrane protein sites. Of the multiple types of nucleoside transporters known to be present in mammalian cells, we observed that ethanol inhibits only one class of facilitative nucleoside transporters, that inhibited by nitrobenzylmercaptopurine riboside. Because there are biochemical similarities between facilitative glucose transporters and nitrobenzylmercaptopurine riboside-sensitive nucleoside transporters, we tested whether ethanol might selectively inhibit a unique class of facilitative glucose transporters. We report here that ethanol inhibits hexose uptake in human lymphocytes and several cell lines expressing the ubiquitous facilitative type 1 glucose transporter (GLUT1). Ethanol inhibition of hexose uptake by GLUT1 is independent of ethanol inhibition of facilitative nucleoside transport. We also determined the ethanol sensitivity of various cloned human facilitative glucose transporters expressed in Chinese hamster ovary cells and we found that ethanol inhibits hexose uptake by GLUT1 but not uptake by GLUT3 or GLUT4 transporters. Our results suggest that a protein motif or motifs present in the GLUT1 amino acid sequence but absent in GLUT3 or GLUT4 proteins may confer ethanol sensitivity.
Mol Pharmacol 1994 Jun
PMID:Selective inhibition by ethanol of the type 1 facilitative glucose transporter (GLUT1). 802 21

The recombinant N-methyl-D-aspartate (NMDA) receptor subunit zeta 1 and the heteromeric subunit combinations epsilon 1/zeta 1, epsilon 2/zeta 1, and epsilon 3/zeta 1 were expressed in Xenopus oocytes and their sensitivities to ethanol were investigated using the two-electrode voltage-clamp technique. NMDA-activated currents in oocytes expressing subunit combinations epsilon 1/zeta 1 or epsilon 2/zeta 1 were significantly inhibited by 50 mM ethanol, whereas NMDA-activated currents associated with the homomeric expression of zeta 1 or the heteromeric epsilon 3/zeta 1 combination were not significantly affected by 50 mM ethanol. Ethanol decreased the maximal amplitude (Emax) of the concentration-response curve for NMDA-activated current, without significantly affecting the EC50. The values of percentage inhibition by ethanol were not significantly different, regardless of the amplitude of current activated by NMDA concentrations from 10 to 250 microM. Different NMDA receptor subunits and subunit combinations exhibited differences in the concentration-response curves for ethanol. NMDA-activated current associated with the epsilon 1/zeta 1 subunit combination was increasingly inhibited by increasing concentrations of ethanol from 25 to 100 mM, whereas 25 mM ethanol elicited nearly maximal inhibition of NMDA-activated current associated with the epsilon 2/zeta 1 subunits, i.e., the inhibition by 50 or 100 nM ethanol was not significantly different. NMDA-activated current associated with the epsilon 3/zeta 1 subunit combination, on the other hand, was significantly inhibited only by 100 mM ethanol, and NMDA-activated current associated with the homomeric zeta 1 subunit was not significantly affected by ethanol concentrations of < or = 100 mM. Because NMDA receptor subunits are differentially distributed throughout the brain, the observations suggest that the differential sensitivity of NMDA receptor subunits to ethanol may contribute to the differences in ethanol sensitivity observed in different types of neurons.
Mol Pharmacol 1994 Feb
PMID:Differential ethanol sensitivity of recombinant N-methyl-D-aspartate receptor subunits. 811 79

Effects of ethanol on the function of Ca(2+)-activated Cl- channels activated by G protein-coupled serotonin (5-hydroxytryptamine, (5-HT)1c) and muscarinic M1 cholinergic receptors were studied in Xenopus oocytes expressing mouse whole-brain mRNA. Ethanol (25-200 mM) inhibited currents evoked by both 5-HT and acetylcholine (ACh), in a concentration-dependent manner. The maximal effect was obtained with 150 mM ethanol, which produced 65 and 49% inhibition of 5-HT and ACh responses, respectively. In the presence of 100 mM ethanol, the EC50 values for both 5-HT and ACh were increased about 4-fold. In contrast, in oocytes expressing rat cerebellar mRNA, metabotropic glutamate receptor responses were much less sensitive to ethanol. To examine potential postreceptor sites for ethanol inhibition, guanosine-5'-O-(3-thio)triphosphate and myo-inositol-1,4,5-trisphosphate were injected intracellularly. Ethanol (100 mM) did not significantly inhibit the currents produced by either guanosine-5'-O-(3-thio)triphosphate or myo-inositol-1,4,5-trisphosphate. Activation of protein kinase C (PKC) by phorbol-12-myristate-13-acetate markedly inhibited 5-HT-induced responses. Both the PKC inhibitor peptide and staurosporine prevented ethanol inhibition of 5-HT-induced responses. Moreover, ethanol, similarly to phorbol-12-myristate-13-acetate and opposite to PKC inhibitors, enhanced the rate of Ca(2+)-activated Cl- current desensitization induced by repeated applications of 5-HT. These results indicate that certain types of receptor-G protein interactions are more susceptible than others to uncoupling by ethanol and that ethanol inhibition of 5-HT1c receptors requires PKC-mediated phosphorylation. We suggest that ethanol may activate PKC, which phosphorylates the receptors, resulting in inhibition of the responses.
Mol Pharmacol 1994 May
PMID:Ethanol inhibits the function of 5-hydroxytryptamine type 1c and muscarinic M1 G protein-linked receptors in Xenopus oocytes expressing brain mRNA: role of protein kinase C. 819 90

The cellular mechanisms by which ethanol affects nervous system function are poorly understood. However, evidence has been accumulating that ethanol can affect the function of neurotransmitter-gated ion channels. Extracellular ATP has recently been reported to produce excitatory actions in the peripheral and central nervous systems by activating ligand-gated ion channels. We studied the effect of ethanol on membrane ion current activated by extracellular ATP in isolated bullfrog dorsal root ganglion neurons, by means of the whole-cell patch-clamp technique. The amplitude of the ATP-activated current was decreased by ethanol in a concentration-dependent manner over the range of 3-500 mM. The average inhibition of 1 microM ATP-activated current by 100 mM ethanol was 64 +/- 3%, and the concentration of ethanol that produced 50% inhibition was 68 mM. Ethanol inhibition of ATP-activated current was not dependent on membrane potential from -80 to +40 mV, and ethanol did not change the reversal potential of ATP-activated current. Ethanol (100 or 400 mM) shifted the ATP concentration-response curve to the right, increasing the EC50 for ATP from 3.0 microM to 6.0 microM or 22.3 microM, respectively, but did not reduce the maximal response to ATP. The results suggest that ethanol inhibits ATP-activated current by increasing the apparent dissociation constant for the ATP receptor.
Mol Pharmacol 1993 Oct
PMID:Ethanol inhibits a neuronal ATP-gated ion channel. 823 36

Long-term treatment with ethanol increases delta-opioid receptor (DOR) expression in the NG108-15 neuroblastoma x glioma hybrid cell line. To determine the underlying mechanism, we studied the effects of ethanol on [3H]diprenorphine binding to intact cells and DOR gene expression in four related clonal neural cell lines. Incubation with 200 mM ethanol for 48 hr increased [3H]diprenorphine binding by 1.4- (N18TG2), 1.8- (NG108-15), 1.9- (N4TG1), and 3.0-fold (N1E-115). Treatment with 25, 50, or 100 mM ethanol for 1 week caused a dose-dependent increase in receptor expression. Receptor up-regulation was associated with an increase in the potency of etorphine for inhibiting prostaglandin E1-stimulated cAMP accumulation. Constitutive DOR expression differed more than 3-fold among the different cell lines and correlated positively with basal cAMP levels. Long-term ethanol treatment increased basal cAMP levels in three of the four cell lines, but did not induce cellular differentiation. Northern blot analysis demonstrated an identical pattern of multiple transcripts in the four cell lines. Ethanol increased the abundance of DOR mRNA by approximately 3-fold in N18TG2 cells and by approximately 5-fold in the remaining cell lines. These findings indicate that clinically relevant concentrations of ethanol regulate DOR expression by increasing the abundance of DOR mRNA. The disparity between the increase in gene expression and ligand binding suggests that ethanol may also modify mRNA translation or receptor processing.
Mol Pharmacol 1993 Dec
PMID:Ethanol increases delta-opioid receptor gene expression in neuronal cell lines. 826 48

The ultrastructure of the human amniotic membrane from normal pregnancies at term, was studied by transmission electron microscopy. The results were analysed by a stereological method which indicates the ratio between the area of intercellular spaces (R1), microvilli (R2) and podocytes (R3) versus the cell area. Addition of ethanol (0.4 g/l) in the external medium decreased R1 and R3 and had no significant effect on R2. Ethanol reduced intercellular space and podocyte exchange surface. Two mM MgCl2 or 2 mM taurine restored R1 and R3 to normal values. The cellular targets of the antagonism between Mg, taurine and ethanol are particularly intercellular spaces and podocytes.
Cell Mol Biol (Noisy-le-grand) 1993 Nov
PMID:Ethanol effect on the ionic transfer through isolated human amnion. II. Cellular targets of the in vitro acute ethanol action and of the antagonism between magnesium, taurine and ethanol. 826 57

The role of brain P450 in the physiology, pharmacology and toxicology of the brain is the subject of this study. Cytochrome P450 was isolated from the brains of rats and quantitated spectrally. The contribution of the known hepatic forms of the enzyme to the forms constitutive in the brain as well as those which are induced by hormones are xenobiotics were characterized on Western blots. We have found that the level of P450 in the brain is increased during pregnancy and lactation, by partial hepatectomy and by ethanol. In each case the profile of P450s induced is different. In pregnancy and lactation the P450 content of the hypothalamic preoptic area and olfactory lobes were increased up to 10-fold and the only subfamily identified on Western blots was 4A. There was no detectable 1A, 2A, 2B, 2C, or 2E1. Ethanol increases the level of brain P450 3- to 5-fold and P450 2C, 2E1 and 4A are induced. Upon partial hepatectomy P450 1A, 2C and 4A were detected on Western blots but there was no 2E1. The inducibility of these forms of P450 in the brain suggests that there is in situ metabolism of steroids, fatty acids, prostaglandins, ethanol and other xenobiotics in the brain and raises questions about the role of brain P450 in the development of tolerance to drugs and the neurotoxicity of xenobiotics. More importantly, the action of neurotransmitters such as dopamine which utilize fatty acids metabolites as intracellular mediators, could be influenced by the levels of 2C and 4A P450s.
J Steroid Biochem Mol Biol 1993 Dec
PMID:Regulation of cytochrome P450 in the central nervous system. 827 35

Ethanol is known to cause a leftward shift of the acetylcholine concentration-response curve for channel opening of the nicotinic acetylcholine receptor (nAcChoR). However, it remains uncertain whether the mechanism underlying ethanol's effect is an increase in the binding affinity of the agonist to the receptor or an increase in the open/closed equilibrium for those receptors occupied by agonist. In the present study, this question was resolved by measuring the efflux of 86Rb+ over 9 msec from Torpedo vesicles after rapid mixing with the partial agonist suberyldicholine with or without ethanol as appropriate. Suberyldicholine's concentration-response curve is bell-shaped. Two actions underlie this bell-shaped curve, namely activation at low concentration (apparent dissociation constant for activation, Ka = 38 microM) and self-inhibition at higher concentration (apparent dissociation constant for inhibition, Kb = 9 mM), but the overlap of these two actions only reduces the maximum observable flux by 20%. Increasing ethanol concentration from 0 to 0.9 M causes: a linear increase in the maximum response of the nAcChoR to suberyldicholine from 5 to 80% of the maximum induced by acetylcholine, a moderate increase in Ka, and no change in Kb. Analysis of our results using the sequential two-site binding model revealed that the main action of ethanol on nAcChoR was to increase the fraction of occupied receptors that open. The equilibrium constant describing this effect changed by 8-fold at anesthetic concentrations. Ethanol also decreased the affinity of suberyldicholine for its self-inhibition site by a comparable amount, suggesting that its main action is to stabilize the open state. In addition, ethanol caused a small increase in suberyldicholine's affinity for the agonist site.
Mol Pharmacol 1994 Jan
PMID:Ethanol stabilizes the open channel state of the Torpedo nicotinic acetylcholine receptor. 830 68


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