Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the mechanisms underlying the bradykinin-evoked changes in intracellular calcium concentration ([Ca2+]i) in Madin Darby canine kidney (MDCK) cells. Bradykinin evoked a [Ca2+]i transient in a dose-dependent manner, measured by fura-2 fluorimetry and digital video imaging. The transient consisted of a rise and a decay and [Ca2+]i returned to baseline without oscillations. External Ca2+ influx occurred, as demonstrated by Mn2+ quench and external Ca2+ removal measurements. Bradykinin acted by stimulating bradykinin B2 receptors as evidenced by blockade by D-arginyl-L-arginlyl-L-prolyl-trans-4-hydroxy-L-prolylglycyl -3-(2-thienyl)-L-alanyl-L-seryl-D-1,2,3,4-tetrahydro-3-isoquinolineca rbonyl-L-(2alpha,3beta,7alphabeta)-octahydro-1 H-indole-2-carbonyl-L-arginine (HOE 140) but not by D-arginyl-L-arginlyl-L-prolyl-trans-4-hydroxy-L-proylglycyl- 3-(2-thienyl)-L-alanyl-L-seryl-D-1,2,3,4-tetrahydro-3-isoquinolinecar bonyl-L-(2alpha,3beta,7alphabeta)-octahydro-1 H-indole-2-carbonyl ([Des-Arg]HOE 140). The [Ca2+]i signal was abolished by 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1 H-pyrrole-2,5-dione (U73122) and partially inhibited by neomycin, implying mediation by phospholipase C. The transient was initiated by a release of Ca2+ from internal stores since it was abolished by pretreatment with thapsigargin or cyclopiazonic acid. The mobilization of the internal Ca2+ store subsequently triggered a 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1 H-imidazole hydrochloride (SKF 96365)-insensitive Ca2+ entry. Pretreatment with carbonylcyanide m-chlorophynylhydrozone and gly-phe-beta-naphthylamide did not alter the transient, thus excluding the participation of mitochondria and lysosomes. Efflux via Ca2+ pumps contributed to the decay of the transient. Efflux via Na+/Ca2+ exchange or sequestration by mitochondria and lysosomes was insignificant. The transient was blunted by the protein kinase C activator phorbol 12-myristate 13-acetate, and was enhanced by the protein kinase C inhibitors sphingosine and chelerythrine, the protein kinase A inhibitor 2,5-di-(t-butyl)-1,4-hydroquinone, N-[2-(p-bromocinnamylamino)ethyl]5-isoquinolinesulfonamide (H-89), the agent 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), and agents that elevated levels of 3',5'-cyclic guanosine monophosphate. The transient did not heterologously desensitize with that evoked by ATP, ADP or UTP.
...
PMID:Bradykinin-evoked Ca2+ mobilization in Madin Darby canine kidney cells. 976 37

Carbamoyl-phosphate synthetase (CPSase) consists of a 120-kDa synthetase domain (CPS) that makes carbamoyl phosphate from ATP, bicarbonate, and ammonia usually produced by a separate glutaminase domain. CPS is composed of two subdomains, CPS.A and CPS.B. Although CPS.A and CPS.B have specialized functions in intact CPSase, the separately cloned subdomains can catalyze carbamoyl phosphate synthesis. This report describes the construction of a 58-kDa chimeric CPSase composed of Escherichia coli CPS.A catalytic subdomains and the mammalian regulatory subdomain. The catalytic parameters are similar to those of the E. coli enzyme, but the activity is regulated by the mammalian effectors and protein kinase A phosphorylation. The chimera has a single site that binds phosphoribosyl 5'-pyrophosphate (PRPP) with a dissociation constant of 25 microM. The dissociation constant for UTP of 0.23 mM was inferred from its effect on PRPP binding. Thus, the regulatory subdomain is an exchangeable ligand binding module that can control both CPS.A and CPS.B domains, and the pathway for allosteric signal transmission is identical in E. coli and mammalian CPSase. A deletion mutant that truncates the polypeptide within a postulated regulatory sequence is as active as the parent chimera but is insensitive to effectors. PRPP and UTP bind to the mutant, suggesting that the carboxyl half of the subdomain is essential for transmitting the allosteric signal but not for ligand binding.
...
PMID:Regulation of an Escherichia coli/mammalian chimeric carbamoyl-phosphate synthetase. 981 25

Bovine adrenal zona fasciculata (AZF) cells express a noninactivating K+ current (IAC) that sets the resting membrane potential and may mediate depolarization-dependent cortisol secretion. External ATP stimulates cortisol secretion through activation of a nucleotide receptor. In whole-cell patch clamp recordings from bovine AZF cells, we found that ATP selectively inhibited IAC K+ current by a maximum of 75.7 +/- 3% (n = 13) with a 50% inhibitory concentration of 1.3 microM. A rapidly inactivating A-type K+ current was not inhibited by ATP. Other nucleotides, including ADP and the pyrimidines UTP and UDP, also inhibited IAC, whereas 2-methylthio-ATP (2-MeSATP) and CTP were completely ineffective. The rank order of potency for six nucleotides was UTP = ADP > ATP > UDP >> 2-MeSATP = CTP. At maximally effective concentrations, UTP, ADP, and UDP inhibited IAC current by 81.4 +/- 5.2% (n = 7), 70.7 +/- 7.2% (n = 4), and 65.2 +/- 7.9% (n = 5), respectively. Inhibition of IAC by external ATP was reduced from 71. 3 +/- 3.2% to 22.8 +/- 4.5% (n = 18) by substituting guanosine 5'-O-2-(thio) diphosphate for GTP in the patch pipette. Inhibition of IAC by external ATP (10 microM) was markedly suppressed (to 17.3 +/- 5.5%, n = 9) by the nonspecific protein kinase antagonist staurosporine (1 microM) and eliminated by substituting the nonhydrolyzable ATP analog 5-adenylyl-imidodiphosphate or UTP for ATP in the pipette. ATP-mediated inhibition of IAC was not altered by the kinase C antagonist calphostin C, the calmodulin inhibitory peptide, or by buffering the intracellular (pipette) Ca++ with 20 mM 1,2-bis-(2-aminophenoxy)ethane-N, N,N',N'-tetraacetic acid. In current clamp recordings, ATP and UTP (but not CTP) depolarized AZF cells at concentrations that inhibited IAC K+ current. These results demonstrate that bovine AZF cells express a nucleotide receptor with a P2Y3 agonist profile that is coupled to the inhibition of IAC K+ channels through a GTP-binding protein. The inhibition of IAC K+ current and associated membrane depolarization are the first cellular responses demonstrated to be mediated through this receptor. Nucleotide inhibition of IAC proceeds through a pathway that is independent of phospholipase C, but that requires ATP hydrolysis. The identification of a new signaling pathway in AZF cells, whereby activation of a nucleotide receptor is coupled to membrane depolarization through inhibition of a specific K+ channel, suggests a mechanism for ATP-stimulated corticosteroid secretion that depends on depolarization-dependent Ca++ entry. This may be a means of synchronizing the stress-induced secretion of corticosteroids and catecholamines from the adrenal gland.
...
PMID:Purine and pyrimidine nucleotides inhibit a noninactivating K+ current and depolarize adrenal cortical cells through a G protein-coupled receptor. 992 30

Mitogen-activated protein kinase (MAPK) cascades underlie long-term mitogenic, morphogenic, and secretory activities of purinergic receptors. In HEK-293 cells, N-ethylcarboxamidoadenosine (NECA) activates endogenous A2BARs that signal through Gs and Gq/11. UTP activates P2Y2 receptors and signals only through Gq/11. The MAPK isoforms, extracellular-signal regulated kinase 1/2 (ERK), are activated by NECA and UTP. H-89 blocks ERK activation by forskolin, but weakly affects the response to NECA or UTP. ERK activation by NECA or UTP is unaffected by a tyrosine kinase inhibitor (genistein), attenuated by a phospholipase C inhibitor (U73122), and is abolished by a MEK inhibitor (PD098059) or dominant negative Ras. Inhibition of protein kinase C (PKC) by GF 109203X failed to block ERK activation by NECA or UTP, however, another PKC inhibitor, Ro 31-8220, which unlike GF 109203X, can block the zeta-isoform, and prevents UTP- but not NECA-induced ERK activation. In the presence of forskolin, Ro 31-8220 loses its ability to block UTP-stimulated ERK activation. PKA has opposing effects on B-Raf and c-Raf-1, both of which are found in HEK-293 cells. The data are explained by a model in which ERK activity is modulated by differential effects of PKC zeta and PKA on Raf isoforms.
...
PMID:A2B adenosine and P2Y2 receptors stimulate mitogen-activated protein kinase in human embryonic kidney-293 cells. cross-talk between cyclic AMP and protein kinase c pathways. 1002 23

1. Average intracellular calcium concentration ([Ca2+]i) and ciliary beat frequency (CBF) were simultaneously measured in rabbit airway ciliated cells in order to elucidate the molecular events that lead to ciliary activation by purinergic stimulation. 2. Extracellular ATP and extracellular UTP caused a rapid increase in both [Ca2+]i and CBF. These effects were practically abolished by a phospholipase C inhibitor (U-73122) or by suramin. 3. The effects of extracellular ATP were not altered: when protein kinase C (PKC) was inhibited by either GF 109203X or chelerythrine chloride, or when protein kinase A (PKA) was inhibited by RP-adenosine 3', 5'-cyclic monophosphothioate triethylamine (Rp-cAMPS). 4. Activation of PKC by phorbol 12-myristate, 13-acetate (TPA) had little effect on CBF or on [Ca2+]i, while activation of PKA by forskolin or by dibutyryl-cAMP led to a small rise in CBF without affecting [Ca2+]i. 5. Direct activation of protein kinase G (PKG) with dibutyryl-cGMP had a negligible effect on CBF when [Ca2+]i was at basal level. However, dibutyryl-cGMP strongly elevated CBF when [Ca2+]i was elevated either by extracellular ATP or by ionomycin. 6. The findings suggest that the initial rise in [Ca2+]i induced by extracellular ATP activates the NO pathway, thus leading to PKG activation. In the continuous presence of elevated [Ca2+]i the stimulated PKG then induces a robust enhancement in CBF. In parallel, activated PKG plays a central role in Ca2+ influx via a still unidentified mechanism, and thus, through positive feedback, maintains CBF close to its maximal level in the continuous presence of ATP.
...
PMID:Interplay between the NO pathway and elevated [Ca2+]i enhances ciliary activity in rabbit trachea. 1006 32

Extracellular nucleotides acting through specific P2 receptors activate intracellular signaling cascades. Consistent with the expression of G protein-coupled P2Y receptors in skeletal tissue, the human osteosarcoma cell line SaOS-2 and primary osteoblasts express P2Y1 and P2Y2 receptors, respectively. Their activation by nucleotide agonists (ADP and ATP for P2Y1; ATP and UTP for P2Y2) elevates [Ca2+]i and moderately induces expression of the c-fos proto-oncogene. A synergistic effect on c-fos induction is observed by combining ATP and parathyroid hormone, a key bone cell regulator. Parathyroid hormone elevates intracellular cAMP levels and correspondingly activates a stably integrated reporter gene driven by the Ca2+/cAMP-responsive element of the human c-fos promoter. Nucleotides have little effect on either cAMP levels or this reporter, instead activating luciferase controlled by the full c-fos promoter. This induction is reproduced by a stably integrated serum response element reporter independently of mitogen-activated protein kinase activation and ternary complex factor phosphorylation. This novel example of synergy between the cAMP-dependent protein kinase/CaCRE signaling module and a non-mitogen-activated protein kinase/ternary complex factor pathway that targets the serum response element shows that extracellular ATP, via P2Y receptors, can potentiate strong responses to ubiquitous growth and differentiative factors.
...
PMID:Signaling in human osteoblasts by extracellular nucleotides. Their weak induction of the c-fos proto-oncogene via Ca2+ mobilization is strongly potentiated by a parathyroid hormone/cAMP-dependent protein kinase pathway independently of mitogen-activated protein kinase. 1031 53

Snake venom cardiotoxins have been recently shown to block the enzymatic activity of phospholipid protein kinase and Na+,K+-ATPase. To understand the molecular basis for the inhibitory effects of cardiotoxin on the action of these enzymes, the nucleotide triphosphate binding ability of cardiotoxin analogue II (CTX II) from the Taiwan cobra (Naja naja atra) venom is investigated using a variety of spectroscopic techniques such as fluorescence, circular dichroism, and two-dimensional NMR. CTX II is found to bind to all the four nucleotide triphosphates (ATP, UTP, GTP, and CTP) with similar affinity. Detailed studies of the binding of dATP to CTX II indicated that the toxin molecule is significantly stabilized in the presence of the nucleotide. Molecular modeling, based on the NOEs observed for the dATP.CTX II complex, reveals that dATP binds to the CTX II molecule at the groove enclosed between the N- and C-terminal ends of the toxin molecule. Based on the results obtained in the present study, a molecular mechanism to account for the inhibition of the enzymatic activity of the phospholipid-sensitive protein kinase and Na+,K+-ATPase is also proposed.
...
PMID:Binding of nucleotide triphosphates to cardiotoxin analogue II from the Taiwan cobra venom (Naja naja atra). Elucidation of the structural interactions in the dATP-cardiotoxin analogue ii complex. 1036 32

The URA7-encoded CTP synthetase [EC 6.3.4.2, UTP:ammonia ligase (ADP-forming)] in the yeast Saccharomyces cerevisiae is phosphorylated on a serine residue and stimulated by cAMP-dependent protein kinase (protein kinase A) in vitro. In vivo, the phosphorylation of CTP synthetase is mediated by the RAS/cAMP pathway. In this work, we examined the hypothesis that amino acid residue Ser424 contained in a protein kinase A sequence motif in the URA7-encoded CTP synthetase is the target site for protein kinase A. A CTP synthetase synthetic peptide (SLGRKDSHSA) containing the protein kinase A motif was a substrate (Km = 30 microM) for protein kinase A. This peptide also inhibited (IC50 = 45 microM) the phosphorylation of purified wild-type CTP synthetase by protein kinase A. CTP synthetase with a Ser424 --> Ala (S424A) mutation was constructed by site-directed mutagenesis. The mutated enzyme was not phosphorylated in response to the activation of protein kinase A activity in vivo. Purified S424A mutant CTP synthetase was not phosphorylated and stimulated by protein kinase A. The S424A mutant CTP synthetase had reduced Vmax and elevated Km values for ATP and UTP when compared with the protein kinase A-phosphorylated wild-type enzyme. The specificity constants for ATP and UTP for the S424A mutant CTP synthetase were 4.2- and 2.9-fold lower, respectively, when compared with that of the phosphorylated enzyme. In addition, the S424A mutant enzyme was 2.7-fold more sensitive to CTP product inhibition when compared with the phosphorylated wild-type enzyme. These data indicated that the protein kinase A target site in CTP synthetase was Ser424 and that the phosphorylation of this site played a role in the regulation of CTP synthetase activity.
...
PMID:Identification of Ser424 as the protein kinase A phosphorylation site in CTP synthetase from Saccharomyces cerevisiae. 1039 61

The aim of this study was to investigate the stimulating effects on arachidonic acid release of P2Y1 and P2Y2 receptor-selective agonists, 2-methylthio-ATP (2MeSATP) and UTP, respectively, in bovine pulmonary artery endothelial cells. Exposure of cells to 2MeSATP and UTP led to the release of arachidonic acid, a response which was abolished by the removal of extracellular Ca2+ and methyl arachidonyl fluorophosphonate. Phorbol 12-myristate 13-acetate (PMA) itself not only stimulated arachidonic acid release but also played a permissive role in the response to UTP. However, PMA failed to enhance the arachidonic acid response induced by 2MeSATP, probably due to greater attenuation of the [Ca2+]i increase caused by 2MeSATP than UTP. Inhibition of protein kinase C with Ro 31-8220 (1-[3-(amidinothio) propyl-1H-indoyl-3-yl]-3-(1-methyl-1H-indoyl-3-yl)-maleimide -methane sulphate) and staurosporine, but not with Go 6976 (12-(-2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-indolo(2, 3-a)pyrrolo(3,4-c)carbazole), reduced the arachidonic acid response of 2MeSATP, UTP and PMA. PMA-induced potentiation of the UTP response reached a maximum after a 1-h preincubation, then declined and eventually lost its effect when the preincubation lasted up to 8 h. Among the protein kinase C isoforms present in endothelial cells, betaI and epsilon could be down-regulated by treatment with PMA for 4-24 h. PD 098059 (2-(2-Amino-3-methoxyphenyl)-4H-1-benzopyran-4-one) inhibited extracellular signal-regulated protein kinase activation, cytosolic phospholipase A2 phosphorylation and arachidonic acid release caused by 2MeSATP, UTP and PMA. Taken together, our results demonstrate that P2Y1 and P2Y2 purinoceptors mediate arachidonic acid release by activating cytosolic phospholipase A2 through an elevation of [Ca2+]i and protein kinase C epsilon-, extracellular signal-regulated protein kinase-dependent phosphorylation.
...
PMID:Protein kinase C epsilon-dependent pathway of extracellular signal-regulated protein kinase activation by P2Y1 and P2Y2 purinoceptors that activate cytosolic phospholipase A2 in endothelial cells. 1040 56

Apoptosis has been shown to be involved in endocrine tissue homeostasis as well as regression due to hormone deprivation. The goal of this study was to induce apoptosis and to investigate a potential role of TSH as a survival factor in thyroid follicular cells (FRTL-5) in vitro. Our results indicated that FRTL-5 cells underwent anchorage-dependent apoptosis when plated in the absence of serum and hormones, but when the cells became attached to the substrate by addition of TSH in the medium, apoptosis was prevented. The apoptosis was evaluated by positive terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labeling staining, typical apoptotic bodies by electron microscopy, DNA ladder by gel electrophoresis, and subdiploidy by propidium iodide-stained flow cytometry. TSH was shown to prevent apoptosis and maintain cell viability. cAMP partly mimicked this effect, which was inhibited by a specific inhibitor of protein kinase A, H-89. While investigating the mechanisms of apoptosis, we observed that the phosphorylated focal adhesion kinase was strengthened by TSH. Furthermore, FRTL-5 cells were found to undergo growth arrest in the G1 phase in the absence of TSH, accompanied by an elevated level of cyclin-dependent kinase inhibitor, p27, and a decreased level of cyclin D. In contrast, TSH promoted transition from G1 to S phase by decreasing P27 protein and increasing cyclin D expression. We concluded that in addition to regulating growth and differentiation, TSH may function as a survival factor in thyroid cells by preventing anchorage-dependent apoptosis in FRTL-5 cells partly via the cAMP pathway.
...
PMID:Thyrotropin prevents apoptosis by promoting cell adhesion and cell cycle progression in FRTL-5 cells. 1057 64


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

---