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)

Elevated intracellular Ca(2+) triggers numerous signaling pathways including protein kinases such as the calmodulin-dependent kinases (CaMKs) and the extracellular signal-regulated kinases (ERKs). In the present study we examined Ca(2+)-dependent "cross-talk" between these two protein kinase families. Using a combination of pharmacological inhibitors and dominant-negative kinases (dnKinase), we identified a requirement for CaMKK acting through CaMKI in the stimulation of ERKs upon depolarization of the neuroblastoma cell line, NG108. Depolarization stimulated prolonged ERK and JNK activation that was blocked by the CaMKK inhibitor, STO-609; this inhibition of ERK activation by STO-609 was rescued by expression of a STO-609-insensitive mutant of CaMKK. However, activation of ERK by epidermal growth factor or carbachol were not suppressed by inhibition of CaMKK, indicating specificity for this "cross-talk." To identify the downstream target of CaMKK that mediated ERK activation upon depolarization, dnKinases were expressed. The dnCaMKI completely suppressed ERK2 activation whereas dnAKT/PKB or nuclear-targeted dnCaMKIV, other substrates for CaMKK, were not inhibitory. ERK activation upon depolarization or transfection with constitutively active (ca) CaMKI was blocked by dnRas. Additionally, depolarization of NG108 cells promoted neurite outgrowth, and this effect was blocked by inhibition of either CaMKK (STO-609) or ERK (UO126). Co-transfection with caCaMKK plus caCaMKI also stimulated neurite outgrowth that was blocked by inhibition of ERK (UO126). These data are the first to suggest that ERK activation and neurite outgrowth in response to depolarization are mediated by CaMKK activation of CaMKI.
 ...
PMID:Calcium activation of ERK mediated by calmodulin kinase I. 1515 Feb 58

Until today, 14 isoforms of mammalian calpains have been identified, including calpain-5. The C. elegans calpain-5 homologue tra-3 is reported to be essential for necrotic neuronal cell death. In this study, we cloned and characterized rat calpain-5, which is highly homologous to human and mouse sequences. The nucleotide sequence is 87% and 93% identical with human and mouse calpain-5, respectively. The protein sequence is well conserved, showing 96% identity in mouse and 92% in human. RT-PCR analysis revealed strong expression of calpain-5 in rat lungs, kidneys, and brain while week expression in heart, whereas in rat brain regions it is ubiquitously expressed. The mRNA expression in different human tissues showed equal expression. However, in human brain regions calpain-5 was strongly expressed in hypothalamus, thalamus, cerebellum, and frontal lobe. Western blot analysis on human neuroblastoma SH-SY5Y cells demonstrated calcium-dependent processing of calpain-5, despite the absence of calmodulin-like domain.
 ...
PMID:Molecular cloning and characterization of rat and human calpain-5. 1546 80

Although corticotropin-releasing hormone (CRH) plays a pivotal role in the regulation of the hypothalamo-pituitary-adrenal axis, the mechanism of CRH gene expression in the neuronal cell is not completely understood. In this study, we examined the transcriptional regulation of human CRH gene 5'-promoter, using a human BE(2)C neuroblastoma cell line expressing intrinsic CRH. In particular, we focused on the involvement of calmodulin kinases (CaMKs), which are known to play an important role in excitation-induced gene expression through the rise in intracellular calcium in the central nervous system. RT-PCR analysis confirmed the expression of CaMK as well as CRH mRNA in BE(2)C cells. When we introduced approximately 1.1 kb of the 5'-promoter region of the human CRH fused with luciferase reporter gene into the cells, a substantial transcriptional activity was observed, and this was further increased by the activation of the cAMP/PKA pathway. We then examined the effect of activation of CaMKs by introducing the expression vectors of each kinase, revealing a potent stimulatory effect of CaMKIV, but no effect of CaMKII. Depolarization of the cells caused an increase in CRH promoter activity, which was completely abolished by the treatment with the CaMK antagonist K252a. Interestingly, KCREB, a dominant negative form of CREB, antagonized the effect of the CaMKIV-mediated effect. Altogether, we conclude that not only the cAMP/PKA but also the calcium/CaMKIV signaling pathway is involved in the regulation of CRH gene expression. Furthermore, CREB is thought to be involved in CaMK- as well as cAMP/PKA-mediated CRH gene expression. Since the CRH gene is expressed in the neuronal cells of the hypothalamus, the calcium/CaMKIV signaling pathway may play an important role in the excitation-mediated regulation of CRH synthesis.
 ...
PMID:Calcium/calmodulin kinase IV pathway is involved in the transcriptional regulation of the corticotropin-releasing hormone gene promoter in neuronal cells. 1559 Oct 24

Here we present a basic concept and several examples of methods of analysis for chemicals that disrupt cellular signaling pathways, in view of risk assessment for potential endocrine disrupting chemicals (EDCs). The key cellular signaling pathways include 1) ER/coactivator interaction, 2) AR translocation into the nucleus, 3) ER/NO/sGC/cGMP, 4) ER/Akt, 5) ER/Src, 6)ER/Src/Grb2, and 7) ER/Ca2+/CaM/CaMK pathways. These were visualized in relevant live cells using newly developed fluorescent and bioluminescent probes. Changes in cellular signals were thereby observed in nongenomic pathways of steroid hormones upon treatment of the target cells with steroid hormones and related chemicals. This method of analysis appears to be a rational approach to high-throughput prescreening (HTPS) of biohazardous chemicals, EDCs, in particular. Also described was the screening of gene expression by serial analysis of gene expression and gene chips upon applying EDCs to breast cancer cells, mouse livers, and human neuroblastoma NB-1 cells.
 ...
PMID:Methods of analysis for chemicals that disrupt cellular signaling pathways: risk assessment for potential endocrine disruptors. 1579 60

Melatonin regulates circadian and seasonal physiology via melatonin receptors expressed in the brain. However, little is known about the signal transduction mechanisms that mediate the action of melatonin in neuronal cells. To begin to address this issue, we expressed the human MT(1) receptor in the human neuroblastoma SH-SY5Y cell line. In this cell line, melatonin acutely stimulated cAMP synthesis through a calcium-calmodulin dependent pathway. This stimulatory effect was independent of an interaction with G(i) or G(s) G proteins and dependent upon internal calcium stores. Melatonin also potentiated forskolin-activated cAMP synthesis. Differentiation of the neuroblastoma cells with retinoic acid to the neuronal phenotype did not alter the ability of melatonin to acutely stimulate cAMP. These data may be relevant to the neuronal action of melatonin and highlight the importance of the cellular context of expression of melatonin and other G protein-coupled receptors.
 ...
PMID:The human MT1 melatonin receptor stimulates cAMP production in the human neuroblastoma cell line SH-SY5Y cells via a calcium-calmodulin signal transduction pathway. 1579 69

Membrane-associated guanylate kinases (MAGUKs) are cytoplasmic multi-domain proteins that serve as scaffold proteins at cell junctions and synapses. Calmodulin-associated serine/threonine kinase (CASK) stabilizes the integrity of synapses in the brain. Additionally, CASK is capable of acting as a transcriptional co-activator and localizes to neuronal nuclei in the developing brain. We have recently described CASK localization to both the pre- and post-synaptic membranes of the neuromuscular junction (NMJ), where it forms a complex with discs large (Dlg). CASK also localizes to some, but not all nuclei in adult mouse skeletal muscle. To begin to dissect the roles of CASK in the cellular components of the NMJ, we investigated the localization of CASK during differentiation in cell culture models of skeletal muscle and motor neurons. We demonstrate that CASK localizes to the nucleus in undifferentiated myoblasts, but is pre-dominantly in the cytoplasm in differentiated myotubes of the C2C12 myogenic cell line. We also show nuclear localization of both CASK and Dlg in a motor neuron-neuroblastoma hybrid cell line, MN-1, suggesting a role for CASK and Dlg in nuclei of neurons in the peripheral nervous system. Finally, we demonstrate that CASK and Dlg do not co-cluster with acetylcholine receptors in C2C12 myotubes in response to agrin or laminin treatment, suggesting a novel mechanism of recruitment to the NMJ that is independent of acetylcholine receptor and utrophin complexes. These studies delineate important developmental characteristics of CASK and Dlg, and suggest dual roles for these proteins in both the skeletal muscle and motor neuron components of the NMJ.
 ...
PMID:CASK localizes to nuclei in developing skeletal muscle and motor neuron culture models and is agrin-independent. 1596 5

FK506 and FK506-derived inhibitors of the FK506-binding protein (FKBP)-type peptidylprolyl cis/trans-isomerases (PPIase) display potent neuroprotective and neuroregenerative properties in various neurodegeneration models, showing the importance of neuroimmunophilins as targets for the treatment of acute and chronic neurodegenerative diseases. However, the PPIase activity targeted by active site-directed ligands remains unknown so far. Here we show that neurotrophic FKBP ligands, such as GPI1046 and N-[methyl(ethoxycarbonyl)]cycloheximide, inhibit the calmodulin/Ca(2+) (CaM/Ca(2+))-regulated FKBP38 with up to 80-fold higher affinity than FKBP12. In contrast, the non-neurotrophic rapamycin inhibits FKBP38.CaM/Ca(2+) 500-fold less affine than other neuroimmunophillins. In the context of the high expression of FKBP38 in neuroblastoma cells, these data suggest that FKBP38.CaM/Ca(2+) inhibition can mediate neurotrophic properties of FKBP ligands. The FKBP38-specific cycloheximide derivative, N-(N',N'-dimethylcarboxamidomethyl)cycloheximide (DM-CHX) was synthesized and used in a rat model of transient focal cerebral ischemia. Accordingly, DM-CHX caused neuronal protection as well as neural stem cell proliferation and neuronal differentiation at a dosage of 27.2 mug/kg. These effects were still dominant, if DM-CHX was applied 2-6 h post-insult. In parallel, sustained motor behavior deficits of diseased animals were improved by drug administration, revealing a potential therapeutic relevance. Thus, our results demonstrate that FKBP38 inhibition by DM-CHX regulates neuronal cell death and proliferation, providing a promising strategy for the treatment of acute and/or chronic neurodegenerative diseases.
 ...
PMID:The specific FKBP38 inhibitor N-(N',N'-dimethylcarboxamidomethyl)cycloheximide has potent neuroprotective and neurotrophic properties in brain ischemia. 1654 4

Gem is a member of the RGK family of GTP-binding proteins within the Ras superfamily possessing a ras-like core and terminal extensions. We have used a variety of cell-based assays to investigate the physiological role of Gem and combined these assays with site-directed mutagenesis of Gem protein to identify the sites responsible for regulation of Gem activity. One function of Gem that has been explained is the inhibition of Rho kinase (ROK)-mediated cytoskeletal rearrangement. Transient expression of Gem in endothelial cells and stable transfection of fibroblasts resulted in decreased stress fiber formation and focal adhesion assembly. A neurite extension model using N1E-115 murine neuroblastoma showed that Gem inhibits actinomyosin-related contractility by specifically opposing ROKbeta activity. Phospho-specific antibodies were used in Western blot analysis to show that Gem prevents phosphorylation of the regulatory subunit of myosin light chain and myosin phosphatase by ROKbeta. On the contrary, LIMK, another substrate of ROKbeta, was unaffected by Gem expression as demonstrated by an in vitro kinase assay, suggesting that Gem exerts its effect by changing the substrate specificity of ROKbeta rather than by blocking its catalytic activity. Point mutations of Gem at serines 261 and 289 in the carboxyl-terminus inhibited Gem function, indicating that posttranslational phosphorylation of these serines regulates Gem's effect on cytoskeletal reorganization. Another biological role of Gem is inhibition of voltage-gated calcium channel activity. By use of a PC12 cell model combined with site-directed mutagenesis, we demonstrated that Gem inhibits growth hormone secretion stimulated by calcium influx through L-type calcium channels and that this function is dependent on GTP and calmodulin binding to Gem. The theory and method for the assays discussed previously are reviewed here.
 ...
PMID:Gem protein signaling and regulation. 1675 46

Death-associated protein kinase (DAPK) is a pro-apoptotic, calcium/calmodulin-regulated protein kinase that is a drug discovery target for neurodegenerative disorders. Despite the potential profound physiological role of DAPK in neuronal function and pathophysiology, the endogenous substrate(s) of this kinase and the mechanisms via which DAPK elicits its biological action remain largely unknown. We report here that the mammalian 40S ribosomal protein S6 is a DAPK substrate. Results from immunoprecipitation experiments are consistent with endogenous DAPK being associated with endogenous S6 in rat brain. When S6 is a component of the 40S ribosomal subunit complex, DAPK selectively phosphorylates it at serine 235, one of the five sites in S6 that are phosphorylated by the S6 kinase family of proteins. The amino acid sequence flanking serine 235 matches the established pattern for DAPK peptide and protein substrates. Kinetic analyses using purified 40S subunits revealed a K(m) value of 9 microM, consistent with S6 being a potential physiological substrate of DAPK. This enzyme-substrate relationship has functional significance. DAPK suppresses translation in rabbit reticulocyte lysate, and treatment of neuroblastoma cells with a stimulator of DAPK reduces protein synthesis. In both cases, suppression of translation correlates with increased phosphorylation of S6 at serine 235. These results demonstrate that DAPK is a S6 kinase and provide evidence for a novel role of DAPK in the regulation of translation.
 ...
PMID:Death-associated protein kinase phosphorylates mammalian ribosomal protein S6 and reduces protein synthesis. 1708 15

The gamma-aminobutyric acid type A (GABA(A)) receptor is a pentameric ligand-gated ion channel responsible for fast synaptic inhibition in the brain. Phosphorylation of the GABA(A) receptor by serine/threonine protein kinases, at residues located in the intracellular loop between the third and fourth transmembrane domains of each subunit, can dynamically modulate receptor trafficking and function. In this study, we have assessed the effect that Ca(2+)-calmodulin-dependent protein kinase-II (CaMK-II) has on GABA(A) receptors. The intracellular application of preactivated CaMK-II failed to modulate the function of alphabeta and alphabetagamma subunit GABA(A) receptors heterologously expressed in human embryonic kidney (HEK)293 cells. However, application of similarly preactivated alpha-CaMK-II significantly potentiated the amplitudes of whole-cell GABA currents recorded from rat cultured cerebellar granule neurons and from recombinant GABA(A) receptors expressed in neuroblastoma, NG108-15, cells. The modulation by alpha-CaMK-II of current amplitude depended upon the subunit composition of GABA(A) receptors. alpha-CaMK-II potentiated GABA currents recorded from alpha1beta3 and alpha1beta3gamma2 GABA(A) receptors, but was unable to functionally modulate beta2 subunit-containing receptors. Similar results were obtained from beta2 -/- mouse cerebellar granule cell cultures and from rat granule cell cultures overexpressing recombinant alpha1beta2 or alpha1beta3 GABA(A) receptors. alpha-CaMK-II had a greater effect on the modulation of GABA responses mediated by alpha1beta3gamma2 compared with alpha1beta3 receptors, indicating a possible role for the gamma2 subunit in CaMK-II-mediated phosphorylation. In conclusion, CaMK-II can upregulate the function of GABA(A) receptors expressed in neurons or a neuronal cell line that is dependent on the beta subunit co-assembled into the receptor complex.
 ...
PMID:CaMK-II modulation of GABA(A) receptors expressed in HEK293, NG108-15 and rat cerebellar granule neurons. 1710 Aug 39


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