Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alanyl aminopeptidase (AAP-S) was purified to homogeneity from rat liver cytosol. The molecular weight of the purified enzyme was calculated to be approximately 100,000 on Sephacryl S-200 HR and to be 90,000 on SDS-PAGE in the presence of beta-mercaptoethanol. These findings suggested that the enzyme exists as a monomeric form in rat liver cytosol. The enzyme rapidly hydrolyzed the substrates Ala-, Tyr- and Met-MCAs, and moderately hydrolyzed Arg-, Lys-, Leu-, Phe- and Lys-Ala-MCAs at pHs ranging from 7.5to 8.0. The enzyme also hydrolyzed several amino acid 4-methyl-coumaryl-7-amide (MCA) substrates. The order for k(cat)/Km values of AAP-S at the optimal pH (pH 7.5) was Lys->Met->Arg->Ala->Leu->Phe->Tyr->Lys-Ala-MCAs. It was strongly inhibited by bestatin, leuhistin, actinonin, amastatin, 1, 10-phenanthroline, PCMBS, Zn2+, Cd2+, Co2+, Cu2+ and Hg2+, and puromycin. The amino acid sequence of the first 43 residues of the enzyme was determined as Pro1-Glu-Lys-Arg-Pro5-Phe-Glu-Arg-Leu-Pro10-Thr-Glu-Val-Ser-Pro 15-Ile-Asn-Tyr-Ser-Leu20-(Cys)-Leu-Lys-Pro-Asp25-Leu-Leu- Asp-Phe-Thr30-Phe-Glu-Gly-Lys-Leu35-Glu-Ala-Ala-Ala-Gln40 -Val-Arg-Gln-. This N-terminal amino acid sequence is almost identical with those of puromycin-sensitive enkephalin-degrading aminopeptidases in rat and human brains, and the mouse neuroblastoma cell line Neuro2A. These findings suggest that the AAP-S from rat liver cytosol is a puromycin-sensitive aminopeptidase. Furthermore, with immunohistochemistry the enzyme was strongly stained in the cytosol of the rat liver cells.
 ...
PMID:Isolation and characterization of an alanyl aminopeptidase from rat liver cytosol as a puromycin-sensitive enkephalin-degrading aminopeptidase. 968 21

Recently, there have been several reports describing the cloning and characterization of the novel family of protein tyrosine phosphatase-like receptor molecules (known as IA-2 and PTP-NP/PTP-IAR/IA-2beta/phogrin), which may act as autoantigens in diabetes. Here, we report the molecular characterization and chromosomal localization of a new isoform of this family in brain termed PTP-NP-2 (for PTP-NP tyrosine phosphatase isoform), and its function in rat primary hippocampal neurons. PTP-NP-2 has 48% identity to IA-2. The principal difference between PTP-NP-2 and PTP-NP is a 17-amino-acid insert near the N-terminus of PTP-NP that is absent in PTP-NP-2. Genomic DNA analysis indicates that the 17-amino-acid insert is coded by a separate exon, suggesting that both IA-2beta and PTP-NP-2 are isoforms arising by alternate splicing of the same gene. Reverse transcriptase-PCR revealed that both isoforms are present in human SH-SY5Y neuroblastoma cells. PTP-NP-2 mRNA expression is highly restricted, with a 5.5-kb specific transcript in human fetal and adult brain and 5.5 and 3. 8 kb in human adult pancreas. SH-SY5Y neuroblastoma and U87-MG glioblastoma cells showed specific transcripts of 5.5 and 3.8<HSP SP = "0.25">kb, respectively, indicating the existence of several isoforms of this molecule in the nervous system. The human gene encoding PTP-NP-2 was assigned to human chromosome 7q22-qter using Southern blot analysis of genomic DNAs from rodent/human somatic hybrid cell lines. Confocal microscopy analyses of rat primary hippocampal neurons revealed that PTP-NP-2 is abundantly expressed on synaptic boutons in primary neurons. Wild-type PTP-NP-2 showed no measurable tyrosine phosphatase activity using an in-vitro pNPP assay. Examination of the PTP-NP-2 catalytic consensus sequence revealed that this sequence differed from the typical tyrosine phosphatase-domain consensus sequence by an alanine to aspartate change (amino acid 930). Mutation of aspartate 930 to alanine produced a catalytically active enzyme, suggesting that native PTP-NP and its isoform PTP-NP-2 are catalytically inactive receptor protein tyrosine phosphatase homologues. Taken together, these results indicate that the tyrosine phosphatase PTP-NP-2 is a new isoform of PTP-NP tyrosine phosphatase, is expressed on synaptic boutons and may participate in the regulation of synaptic bouton endocytosis.
 ...
PMID:Characterization and chromosomal localization of PTP-NP-2, a new isoform of protein tyrosine phosphatase-like receptor, expressed on synaptic boutons. 971 34

A structure-activity study utilising 36 synthetic Ala-analogues of the 36-residue oligopeptide neuropeptide Y (NPY) has been performed with mucosal preparations from the rat jejunum (Y2-like receptor) and compared with receptor displacement binding in the human neuroblastoma cell lines, SMS-KAN, (Y2-receptors) and SK-N-MC cells (Y1-receptors). Each amino acid of the natural sequence was replaced by L-alanine, and the four intrinsic alanine residues at position 12, 14, 18 and 23 were replaced by glycine. The purified peptides were characterized by electrospray mass spectrometry, analytical HPLC and amino acid analysis. Binding was investigated using membranes prepared from either SMS-KAN or SK-N-MC cells. The activity of each Ala-NPY analogue was assessed in mucosal preparations of rat jejunum, where NPY and PYY exert antisecretory responses which are Y2-like in pharmacology. Fourteen analogues with L-alanine replacements at position 3, 5, 8, 13, 20, 21, 22, 26, 27, 28, 29, 30, 34 and 36 were selected, none of which exhibited any antagonism of NPY responses. An order of agonist potency showed [Ala3] NPY and [Ala30] NPY equipotent with NPY, a 4-20-fold loss of activity with [Ala5] NPY, [Ala13] NPY, [Ala20] NPY, [Ala21] NPY and [Ala22] NPY; a 50-100-fold loss of activity, [Ala8] NPY, [Ala27] NPY, [Ala28] NPY and [Ala36] NPY, while [Ala34] NPY was inactive. This structure-activity relationship is similar to, but not the same as that observed in Y2-expressing SMS-KAN cells.
 ...
PMID:Structure-activity relationships with neuropeptide Y analogues: a comparison of human Y1-, Y2- and rat Y2-like systems. 980 88

Signaling of G protein-coupled receptors is terminated by phosphorylation of intracellular serine and threonine residues. Resensitization of these receptors requires internalization and subsequent dephosphorylation. We have recently shown that the resensitization rate of the rat micro opioid receptor (MOR) isoforms MOR1 and MOR1B is mainly determined by the amino acid composition of their alternatively spliced C-terminal tails. Upon agonist stimulation, MOR1B passes through an accelerated cycle of receptor endocytosis and reactivation, which in turn promotes a greater resistance to agonist-induced desensitization, as compared with MOR1. Given the fact that MOR1B lacks only one putative phosphorylation site (T394 of MOR1), we replaced this threonine by an alanine and stably expressed the wild-type MOR1 and its T394A mutant in mouse neuroblastoma Neuro2a cells. We show that during prolonged [D-Ala2, MePhe4, Gly5-ol]enkephalin exposure (5 h), the T394A receptor mutant desensitized at a slower rate than MOR1. In contrast, T394A is more rapidly removed from the cell surface than MOR1, as determined by flow cytometry using epitope-tagged receptors. This fast internalization was followed by immediate resensitization of T394A during 20 min of agonist removal while the wild-type MOR1 remained inactive. Similar to MOR1B, rapid internalization and reactivation of T394A may explain its delayed desensitization. These findings suggest that T394 represents a negative regulatory signal for MOR1 internalization. Furthermore, phosphorylation of this threonine residue may influence the time course of micro opioid receptor resensitization.
 ...
PMID:Replacement of threonine 394 by alanine facilitates internalization and resensitization of the rat mu opioid receptor. 992 17

Differences in the specificity of coupling of delta-opioid receptor with G-protein have been reported in the literature. We have observed a differential desensitization of delta-opioid receptors, endogenously expressed in the neuroblastoma cell line SK-N-BE, induced by peptide and alkaloid agonists. By combining photoaffinity labelling of receptor-activated G-proteins with [alpha-(32)P]azidoanilide-GTP and an anti-sense oligodeoxynucleotide strategy, we examined whether the chemical nature of opioid agonists, alkaloid or peptide, has a critical role in determining a G(i)alpha/G(o)alpha-protein-selective activation by the human delta-opioid receptors. Etorphine, a non-selective alkaloid agonist, was shown to stimulate the incorporation of [alpha-(32)P]azidoanilide-GTP into G(i)alpha1, G(i)alpha2, G(i)alpha3 and pertussis-toxin-insensitive Galpha subunits. In contrast, [d-Pen(2),d-Pen(5)]enkephalin (DPDPE; Pen is penicillamine) and Tyr-d-Ala-Phe-Asp-Val-Val-Gly-NH(2) (deltorphin I), selective peptide agonists, mainly activated G(i)alpha2 and G(o)alpha2 subunits. The 'knock-down' of G(o)alpha2 subunits by anti-sense oligodeoxynucleotides selectively decreased the inhibition of adenylate cyclase induced by DPDPE and deltorphin I, whereas anti-sense oligodeoxynucleotides directed against G(i)alpha2 subunits only decreased the potency of etorphine in inhibiting cAMP accumulation. These results suggest that the nature of the agonist, peptide or alkaloid is critical in determining the interaction between human delta-opioid receptors and Galpha subunits.
 ...
PMID:Differential G-protein activation by alkaloid and peptide opioid agonists in the human neuroblastoma cell line SK-N-BE. 1043 2

Inhibitors of histone deacetylase (HDAC) have been shown to have both apoptotic and differentiating effects on various tumor cells. M-carboxycinnamic acid bishydroxamide (CBHA) is a recently developed hybrid polar compound structurally related to hexamethylene bisacetamide. CBHA is a potent inhibitor of HDAC activity. CBHA induces cellular growth arrest and differentiation in model tumor systems. We undertook an investigation of the effects of CBHA on human neuroblastoma cell lines in vitro. When added to cultures of a panel of neuroblastoma cell lines, CBHA induced the accumulation of acetylated histones H3 and H4, consistent with the inhibition of HDAC. Concentrations of CBHA between 0.5 microM and 4 microM led to apoptosis in nine of nine neuroblastoma cell lines. Apoptosis was assessed by DNA fragmentation analysis and the appearance of a sub-G1 (<2N ploidy) population by flow cytometric analysis. The addition of a caspase inhibitor (benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone) completely abrogated CBHA-induced apoptosis in three of three cell lines. The addition of cycloheximide greatly reduced CBHA-induced apoptosis, suggesting that apoptotic induction was dependent on de novo protein synthesis. In addition, CBHA induced the expression of both CD95 (APO-1/Fas) and CD95 ligand within 12 h. The effect of CBHA on human neuroblastoma cells suggests that this agent and structurally related synthetic hybrid polar compounds have therapeutic potential for the treatment of this malignancy.
 ...
PMID:Hybrid polar histone deacetylase inhibitor induces apoptosis and CD95/CD95 ligand expression in human neuroblastoma. 1048 88

Abeta peptides are major components of the amyloid plaques that characterize Alzheimer's disease. The enzyme activities (beta- and gamma-secretases) involved in generating Abeta from amyloid precursor protein (APP) are unidentified. It has been suggested that prolylendopeptidase (PEP), an oligopeptidase that normally cleaves after proline residues, could also cleave after the alanine at position 42 of Abeta to generate Abeta42. We investigated whether inhibition of PEP activity in human neuroblastoma cells affected Abeta levels in cell culture media. An SH-SY5Y cell line expressing SPA4CT, encoding the C-terminal 100 residues of APP and the signal sequence, was used. Only gamma-secretase activity is required for Abeta production in this cell line. The PEP inhibitor Fmoc-AlaPro-CN (10 microM) reduced PEP activity in these cells by approximately 95% in the absence of significant toxicity, but had no effect on Abeta40 or Abeta42 levels in cell culture media. We conclude that PEP is unlikely to be involved in gamma-secretase processing of APP.
 ...
PMID:Inhibition of prolylendopeptidase does not affect gamma-secretase processing of amyloid precursor protein in a human neuroblastoma cell line. 1064 91

RGS proteins comprise a family of proteins named for their ability to negatively regulate heterotrimeric G protein signaling. Biochemical studies suggest that members of this protein family act as GTPase-activating proteins for certain Galpha subunits, thereby accelerating the turn-off mechanism of Galpha and terminating signaling by both Galpha and Gbetagamma subunits. In the present study, we used confocal microscopy to examine the intracellular distribution of several RGS proteins in COS-7 cells expressing RGS-green fluorescent protein (GFP) fusion proteins and in cells expressing RGS proteins endogenously. RGS2 and RGS10 accumulated in the nucleus of COS-7 cells transfected with GFP constructs of these proteins. In contrast, RGS4 and RGS16 accumulated in the cytoplasm of COS-7 transfectants. As observed in COS-7 cells, RGS4 exhibited cytoplasmic localization in mouse neuroblastoma cells, and RGS10 exhibited nuclear localization in human glioma cells. Deletion or alanine substitution of an N-terminal leucine repeat motif present in both RGS4 and RGS16, a domain identified as a nuclear export sequence in HIV Rev and other proteins, promoted nuclear localization of these proteins in COS-7 cells. In agreement with this observation, treatment of mouse neuroblastoma cells with leptomycin B to inhibit nuclear protein export by exportin1 resulted in accumulation of RGS4 in the nucleus of these cells. GFP fusions of RGS domains of RGS proteins localized in the nucleus, suggesting that nuclear localization of RGS proteins results from nuclear targeting via RGS domain sequences. RGSZ, which shares with RGS-GAIP a cysteine-rich string in its N-terminal region, localized to the Golgi complex in COS-7 cells. Deletion of the N-terminal domain of RGSZ that includes the cysteine motif promoted nuclear localization of RGSZ. None of the RGS proteins examined were localized at the plasma membrane. These results demonstrate that RGS proteins localize in the nucleus, the cytoplasm, or shuttle between the nucleus and cytoplasm as nucleo-cytoplasmic shuttle proteins. RGS proteins localize differentially within cells as a result of structural differences among these proteins that do not appear to be important determinants for their G protein-regulating activities. These findings suggest involvement of RGS proteins in more complex cellular functions than currently envisioned.
 ...
PMID:Cytoplasmic, nuclear, and golgi localization of RGS proteins. Evidence for N-terminal and RGS domain sequences as intracellular targeting motifs. 1079 63

A mutant of Bacillus subtilis IMR-NK1, which is used for the production of domestic "natto" in Taiwan, produced high fibrinolytic enzyme activity by solid-state fermentation using wheat bran as medium. In addition, a strong fibrinolytic enzyme was purified from the cultivation media. The purified enzyme was almost homogeneous, as examined by SDS-PAGE and capillary electrophoresis. The enzyme had an optimal pH of 7.8, an optimal temperature of 55 degrees C, and a K(m) of 0.15% for fibrin hydrolysis. The molecular mass estimated by gel filtration was 31.5 kDa, and the isoelectric point estimated by isoelectric focusing electrophoresis was 8.3. The enzyme also showed activity for hydrolysis of fibrinogen, casein, and several synthetic substrates. Among the synthetic substrates, the most sensitive substrate was N-succinyl-Ala-Ala-Pro-Phe-pNA. PMSF and NBS almost completely inhibited the activity of the enzyme. These results indicate that the enzyme is a subtilisin-like serine protease, similar to nattokinase from Bacillus natto.
 ...
PMID:Potent fibrinolytic enzyme from a mutant of Bacillus subtilis IMR-NK1. 1095 93

Apoptosis of NG108-15 neuroblastoma x glioma hybrid cells (NG108-15 cells) is induced by a morphine alkaloid derivative, buprenorphine hydrochloride (Bph). In a previous report, we used various apoptosis inhibitors to identify the "death pathway," and found that caspase inhibitors Ac-YVAD-CHO (Ac-Tyr-Val-Ala-Asp-CHO) and Ac-DEVD-CHO (Ac-Asp-Glu-Val-Asp-CHO) did not inhibit this particular apoptosis. Here, we tested Z-VAD-FMK (Z-Val-Ala-Asp[OMe]-CH2F) and Z-DEVD-FMK (Z-Asp[OMe]-Glu-[OMe]Val-Asp[OMe]-CH2F) for their ability to inhibit Bph-induced NG108-15 apoptosis. These tri- or tetra-peptide caspase inhibitors have a fluoromethyl ketone in their C-terminus instead of an aldehyde, and thus are more permeable than Ac-YVAD-CHO and AC-DEVD-CHO. Our observations of DNA ladder formation, cell morphology changes, and caspase-3 activities all indicated that these cell membrane-permeable caspase inhibitors completely inhibited the apoptosis, providing strong evidence that this apoptosis occurs through the caspase cascade "death pathway." Our previous report also showed that pretreatment of NG108-15 cells with TPCK (N-tosyl-L-phenylalanyl chloromethyl ketone) prevented DNA fragmentation and decreased the cell viability in Bph-induced apoptosis. The comparison of caspase-3 activities in Bph-induced samples with or without TPCK pretreatment revealed that caspase-3 was activated in both samples. Taken together, these results indicate that the Bph-induced apoptosis of NG108-15 cells occurs via the conventional caspase-dependent death pathway and that TPCK pretreatment results in a DNA ladder-deficient apoptosis.
 ...
PMID:Apoptosis of NG108-15 cells induced by buprenorphine hydrochloride occurs via the caspase-3 pathway. 1096 98


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>