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)

Five protein families are needed to encompass the diversity of cyclic-AMP (cAMP) phosphodiesterases (PDE). Family IV PDEs (PDE IV) specifically hydrolyze cAMP with a low Km, and are selectively inhibited by rolipram (Rp) and related drugs. Cloned cDNAs from rat (r) suggest that the PDE IV family comprises four distinct members, designated A, B, C and D. Using RN from a human lymphocytic B-cell line (43D-Cl2), we have isolated a 3.8-kb cDNA by low-stringency screening using a rat PDE IV member B (r-PDE IVB) probe. Expression of the human (h) cDNA in Escherichia coli results in cAMP-specific PDE activity that is Rp sensitive. A single large open reading frame (ORF) predicts a 564-amino-acid protein with 92.9% identity to r-PDE IVB; at the nucleotide level the identity is 86.3%. This h-PDE IVB clone, HPB106, differs from a related cDNA clone isolated by others from h-monocytes [Livi et al., Mol. Cell. Biol. 10 (1990) 2678-2686]. Our analysis identifies the monocyte clone with r-PDE IVA. Southern blots using a 1.2-kb h-PDE IVB probe at low stringency suggest the presence of additional uncloned human PDE IV family members. Analysis of genomic Southern blots using short specific probes from the h-PDE IVA and h-PDE IVB cDNAs indicates that distinct genes encode these two PDE IV family members. RNA from fractionated normal human leukocytes shows major specific messages of 3.0 and 4.6 kb for h-PDE IVA and 3.7 kb for h-PDE IVB.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The cDNA of a human lymphocyte cyclic-AMP phosphodiesterase (PDE IV) reveals a multigene family. 839 15

The role of the lysosome during the intracellular concentration of diverse mineral elements has been evidenced by the electron probe X-ray microanalysis (EPMA). This highly sensitive technique allows an in situ chemical analysis of any chemical element with an atomic number greater than 11, present in ultra-thin tissue sections. Therefore, it has been demonstrated by using this EPMA that 21 out of the 92 elements of the periodic table, once injected in a soluble form, were selectively concentrated within lysosomes of several types of mammalian cells. Amongst these 21 elements, 15 are concentrated and precipitated in an insoluble from in association with phosphorus whereas the other 6 are precipitated in association with sulphur. Amongst the 15 elements which precipitate with phosphorus in lysosomes, there are: 3 group IIIB elements of the periodic system, (aluminium, gallium and indium); the rare-earth elements (cerium, gadolinium, lanthanum, thulium and samarium); 2 group IVA elements (hafnium and zirconium), two actinides (uranium and thorium) and elements such as chromium and niobium. The 6 elements which precipitate with sulphur comprise the 3 group VIII elements of the classification (nickel, palladium, platinum) and the 3 group IB elements (copper, silver and gold). The mechanisms responsible for this selective concentration involve enzymatic processes and predominantly acid phosphatases for elements precipitating as phosphates and arylsulfatases for elements precipitating with sulphur.
Cell Mol Biol (Noisy-le-grand) 1996 May
PMID:The role of lysosomes in the selective concentration of mineral elements. A microanalytical study. 879 93

We studied the mechanism by which the peptide omega-grammotoxin-SIA inhibits voltage-dependent calcium channels. Grammotoxin at concentrations of > 50 nM completely inhibited inward current carried by 2 mM barium through P-type channels in rat cerebellar Purkinje neurons when current was elicited by depolarizations up to +40 mV. However, outward current (carried by internal cesium) elicited by depolarizations to > +100 mV was either unaffected or enhanced in the presence of toxin. Tail current activation curves showed that grammotoxin shifted the steady state voltage dependence of channel activation by approximately +40 mV. Activation in the presence of toxin was far slower in addition to having altered voltage dependence. Grammotoxin also inhibited N-type calcium channels in rat and frog sympathetic neurons, with changes in channel voltage dependence and kinetics nearly identical to those of P-type channels. Experiments with monovalent ions as the only charge carriers showed that toxin effects on channel activation and kinetics depended on voltage, not on direction of current flow or on the current-carrying ion. Repeated trains of large depolarizations relieved toxin inhibition, as if toxin affinity for activated channels were low. The effects of grammotoxin on gating of P-type channels are very similar to those of omega-Aga-IVA, but combined application of the two toxins showed that grammotoxin binding is not prevented by saturating binding of omega-Aga-IVA. We conclude that grammotoxin potently inhibits both P-type and N-type channels by impeding channel gating and that grammotoxin binds to distinct or additional sites on P-type channels compared with omega-Aga-IVA.
Mol Pharmacol 1997 Dec
PMID:Voltage-dependent inhibition of N- and P-type calcium channels by the peptide toxin omega-grammotoxin-SIA. 941 20

Peptide toxins have proved to be useful agents, both in discriminating between different components of native calcium channel currents and in the molecular isolation and designation of their cloned channel counterparts. Here, we describe the isolation and characterization of the biochemical and physiological properties of a novel 74-amino acid peptide toxin (DW13.3) extracted from the venom of the spider Filistata hibernalis. The subtype specificity of DW13.3 was investigated using calcium channel currents recorded from two separate expression systems and several different cultured mammalian cell preparations. Overall, DW13.3 potently blocked all native calcium channel currents studied, with the exception of T-type currents recorded from GH3 cells. Examination of transiently expressed calcium channels in oocytes showed that DW13.3 had the highest affinity for alpha1A, followed by alpha1B > alpha1C > alpha1E. The affinity of DW13.3 for alpha1B N-type currents varied by 10-fold between expressed channels and native currents. Although block occurred in a similar 1:1 manner for all subtypes, DW13.3 produced a partial block of both alpha1A currents and P-type currents in cerebellar Purkinje cells. Selective occlusion of the P/Q-type channel ligand omega-conotoxin MVIIC (but not omega-agatoxin IVA) from its binding site in Purkinje neurons suggests that DW13.3 binds to a site close to the pore of the channel. The inhibition of different subtypes of calcium channels by DW13.3 reflects a common "macro" binding site present on all calcium channels except T-type.
Mol Pharmacol 1998 Aug
PMID:Inhibition of neuronal calcium channels by a novel peptide spider toxin, DW13.3. 968 83

High voltage-activated (HVA) Ca2+ current (ICa) was recorded from neonatal rat hippocampal and adult rat dorsal root ganglion neurons. In both cell types, (+)-3alpha-hydroxy-5alpha-androstane-17beta-carbonitrile [(+)-ACN], a neuroactive steroid, had no effect on nifedipine- (L-type) or omega-agatoxin IVA- (P-type) sensitive ICa. Selective blockade of N-type current with omega-conotoxin GVIA and of Q-type current with omega-conotoxin MVIIC indicated that (+)-ACN inhibits both N- and Q-type current components in both cell types. Current persisting after blockade of all other current components (R-type) was also sensitive to (+)-ACN. Half-blockade of (+)-ACN-sensitive HVA current occurred in the range of 3-25 microM, with N-type current somewhat more sensitive than Q- or R-type. The (+)-ACN enantiomer, (-)-ACN, and pregnanolone were somewhat less effective at inhibiting total HVA current than (+)-ACN, whereas several steroid analogs, including alfaxalone, were relatively ineffective at inhibiting total HVA current. Neither guanosine-5'-O-(2-thio)diphosphate nor guanosine-5'-O-(3-thio)triphosphate altered the ability of (+)-ACN to inhibit HVA current in dorsal root ganglion neurons, indicating that (+)-ACN acts directly on Ca2+ channels. The partial selectivity exhibited by (+)-ACN among different HVA current components suggests that manipulations of steroid analogues may be a useful strategy in the generation of more selective, more potent, small-molecular-weight HVA channel blockers.
Mol Pharmacol 1998 Sep
PMID:The anesthetic steroid (+)-3alpha-hydroxy-5alpha-androstane-17beta-carbonitrile blocks N-, Q-, and R-type, but not L- and P-type, high voltage-activated Ca2+ current in hippocampal and dorsal root ganglion neurons of the rat. 973 Sep 15

We describe a Czech patient with combined adenine phosphoribosyltransferase (APRT) deficiency (2,8-dihydroxyadenine urolithiasis) and N-acetylgalactosamine-6-sulfate sulfatase (GALNS) deficiency (mucopolysaccharidosis Type IVA, Morquio disease A). Adenine and its extremely insoluble derivative, 2,8-dihydroxyadenine, were identified in the urine, and APRT deficiency was confirmed in erythrocytes. There was excessive excretion of keratan sulfate in the urine, and GALNS deficiency was confirmed in leukocytes. GALNS and APRT are both located on chromosome 16q24.3, suggesting that the patient had a deletion involving both genes. PCR amplification of genomic DNA indicated that a novel junction was created by the fusion of sequences distal to GALNS exon 2 and proximal to APRT exon 3, and that the size of the deleted region was approximately 100 kb. The deletion breakpoints were localized within GALNS intron 2 and APRT intron 2. Several other genes, including the alpha subunit of cytochrome B (CYBA), which is deleted or mutated in the autosomal form of chronic granulomatous disease, are located in the 16q24.3 region, but PCR amplification showed that this gene was present in the proband. A patient with hemizygosity for GALNS deficiency and APRT deficiency has been reported from Japan recently. These findings indicate that: (i) APRT is located telomeric to GALNS; (ii) GALNS and APRT are transcribed in the same orientation (centromeric to telomeric); and (iii) combined APRT/GALNS deficiency may be more common than hitherto realized.
Mol Genet Metab 1999 Sep
PMID:Combined adenine phosphoribosyltransferase and N-acetylgalactosamine-6-sulfate sulfatase deficiency. 1047 85

We have analyzed Ca2+ currents in two neuroblastoma-motor neuron hybrid cell lines that expressed normal or glutamine-expanded human androgen receptors (polyGln-expanded AR) either transiently or stably. The cell lines express a unique, low-threshold, transient type of Ca2+ current that is not affected by L-type Ca2+ channel blocker (PN 200-110), N-type Ca2+ channel blocker (omega-conotoxin GVIA) or P-type Ca2+ channel blocker (Agatoxin IVA) but is blocked by either Cd2+ or Ni2+. This pharmacological profile most closely resembles that of T-type Ca2+ channels [1-3]. Exposure to androgen had no effect on control cell lines or cells transfected with normal AR but significantly changed the steady-state activation in cells transfected with expanded AR. The observed negative shift in steady-state activation results in a large increase in the T-type Ca2+ channel window current. We suggest that Ca2+ overload due to abnormal voltage-dependence of transient Ca2+ channel activation may contribute to motor neuron toxicity in spinobulbar muscular atrophy (SBMA). This hypothesis is supported by the additional finding that, at concentrations that selectively block T-type Ca2+ channel currents, Ni2+ significantly reduced cell death in cell lines transfected with polyGln-expanded AR.
Mol Cell Biochem 2000 Jan
PMID:Increased T-type Ca2+ channel activity as a determinant of cellular toxicity in neuronal cell lines expressing polyglutamine-expanded human androgen receptors. 1072 29

The omega-agatoxin-IVA-sensitive P/Q-type Ca(2+) channel plays a role in insulin release from the pancreatic islets of beta cells. To dissect the molecular mechanisms underlying beta cell expression of the P/Q-type channel, we characterized the 5'-upstream region of the mouse alpha(1A) subunit gene using transgenic mice and HIT insulinoma cells. The E. coli lacZ reporter gene was expressed in pancreatic acini and islets in transgenic mice carrying the 6.3 kb or 3.0 kb of the 5'-upstream region, although those with 1.5 kb or 0. 5 kb of the 5'-upstream region failed to show reporter expression on histological examination. As the expression of alpha(1A)subunit gene could not be detected in acini using RT-PCR analysis, the reporter expression in acini might have been ectopic expression. When linked to the placental alkaline phosphatase reporter gene to examine promoter activity for beta cell expression, the 6.3 kb and 3.0 kb fragment of the 5'-upstream region, but not the smaller 1.5 kb fragment, were able to drive reporter gene expression in HIT cells. The sequence between 3.0 and 1.5 kb upstream of the start codon enhanced thymidine kinase promoter activity in HIT cells, but not in fibroblast NIH3T3 cells. These results suggested that the beta cell-specific elements of the alpha(1A) subunit gene are likely to be located in the distal upstream region (-3021 to-1563) of the 5'-upstream sequence and that the 6.3 kb fragment of the 5'-upstream region alone might be a lack of a negative cis-regulatory element(s) to suppress the alpha(1A) subunit gene expression in acini.
J Mol Endocrinol 2000 Apr
PMID:Analysis of the 5'-upstream region of mouse P/Q-type Ca2+ channel alpha1A subunit gene for expression in pancreatic islet beta cells using transgenic mice and HIT-T15 cells. 1075 23

Mucopolysaccharidosis IVA (MPS IVA; OMIM#253000), a lysosomal storage disorder caused by a deficiency of N -acetylgalactosamine-6-sulfate sulfatase (GALNS), has variable clinical phenotypes. To date we have identified 65 missense mutations in the GALNS gene from MPS IVA patients, but the correlation between genotype and phenotype has remained unclear. We studied 17 missense mutations using biochemical approaches and 32 missense mutations, using structural analyses. Fifteen missense mutations and two newly engineered active site mutations (C79S, C79T) were characterized by transient expression analysis. Mutant proteins, except for C79S and C79T, were destabilized and detected as insoluble precursor forms while the C79S and C79T mutants were of a soluble mature size. Mutants found in the severe phenotype had no activity. Mutants found in the mild phenotype had a considerable residual activity (1.3-13.3% of wild-type GALNS activity). Sulfatases, including GALNS, are members of a highly conserved gene family sharing an extensive sequence homology. Thus, a tertiary structural model of human GALNS was constructed from the X-ray crystal structure of N -acetylgalacto-samine-4-sulfatase and arylsulfatase A, using homology modeling, and 32 missense mutations were investigated. Consequently, we propose that there are at least three different reasons for the severe phenotype: (i) destruction of the hydrophobic core or modification of the packing; (ii) removal of a salt bridge to destabilize the entire conformation; (iii) modification of the active site. In contrast, mild mutations were mostly located on the surface of the GALNS protein. These studies shed further light on the genotype-phenotype correlation of MPS IVA and structure-function relationship in the sulfatase family.
Hum Mol Genet 2000 May 22
PMID:Biochemical and structural analysis of missense mutations in N-acetylgalactosamine-6-sulfate sulfatase causing mucopolysaccharidosis IVA phenotypes. 1081 10

The effects of 2,5-di(tert-butyl)-1,4-benzohydroquinone (tBHQ), a synthetic phenolic antioxidant and a blocker of the sarco-endoplasmic ATPase, were evaluated on low and high voltage-activated Ca(2+) currents (ICas) with rodent dorsal root ganglion, hippocampal, and motor neurons. In all cell types tested, tBHQ (IC(50) = 35 microM) blocked ICa at concentrations used to inhibit sarco-endoplasmic ATPase. This effect was specific to tBHQ because the other sarco-endoplasmic reticulum calcium ATPase pump inhibitors (thapsigargin and cyclopiazonic acid) had no effect. Selective blockade of the N-type current with omega-conotoxin GVIA and of P- (motoneuron) or Q-type currents (hippocampal neuron) with omega-agatoxin IVA indicated that tBHQ inhibited N, P, and Q types of ICa. tBHQ had no effect on nitrendipine-sensitive (L-type) and residual drug-resistant (R-type) ICa, nor on the low voltage-activated T-type ICa. Contrary to neuronal cells, the L-type ICa was inhibited by tBHQ in a differentiated mouse neuroblastoma and rat glioma hybrid cell line. Injection of cDNAs encoding the alpha1A, alpha1B, alpha1C, and alpha1E subunits into oocytes showed that tBHQ blocked ICas at the level of the pore-forming protein. This effect of tBHQ on ICa should be considered when interpreting results obtained with tBHQ used on neuronal preparations. It also may be useful for developing new strategies for the generation of more potent intracellular calcium transient inhibitors.
Mol Pharmacol 2000 Jul
PMID:Sarco-endoplasmic ATPase blocker 2,5-Di(tert-butyl)-1, 4-benzohydroquinone inhibits N-, P-, and Q- but not T-, L-, or R-type calcium currents in central and peripheral neurons. 1086 Sep 23


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