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Query: EC:2.7.11.1 (
protein kinase
)
81,284
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Adenosine is a potent vasodilator of the coronary microvessels and is implicated in the regulation of coronary blood flow during metabolic stress. However, the receptor subtypes and the vasodilatory mechanism responsible for the dilation of coronary microvessels to adenosine remain unclear. In the present study, using an isolated-vessel preparation we demonstrated that porcine coronary arterioles (50-100 microm) dilated concentration-dependently to adenosine, CPA (
adenosine A1 receptor
agonist) and CGS21680 (adenosine A2A receptor agonist). These vasodilations were not altered by the A1 receptor antagonist CPX, but were abolished by the selective A2A receptor antagonist ZM241385, indicating that activation of A2A receptors mediates these vasodilatory responses. The
protein kinase A
inhibitor Rp-8-Br-cAMPS abolished coronary arteriolar dilations to adenylyl cyclase activator forskolin and cAMP analog 8-Br-cAMP, but failed to inhibit adenosine- and CGS21680-induced dilations. The calcium-activated potassium channel inhibitor iberiotoxin also did not affect vasodilations to adenosine and CGS21680. In contrast, the ATP-sensitive potassium (K(ATP)) channel inhibitor glibenclamide abolished vasodilations to adenosine and CGS21680 but did not affect vasodilations to forskolin and 8-Br-cAMP. In addition, the cAMP level in coronary microvessels was not increased by adenosine or CGS21680. The results from RT/PCR and in situ hybridization indicated that adenosine A2A receptor mRNA was encoded in coronary arterioles and the left anterior descending (LAD) artery but not in cardiomyocytes, whereas the A1 receptor transcript was detected in the LAD artery and cardiomyocytes but not in arterioles. Similarly, adenosine A1 and A2A proteins were expressed in the LAD artery, but only A2A receptors were expressed in coronary arterioles. Collectively, these functional data suggest that coronary arteriolar dilation to adenosine is primarily mediated by the opening of K(ATP) channels through activation of A2A receptors. This conclusion is corroborated by the molecular data showing that coronary arterioles only express adenosine A2A receptors. Furthermore, the dilation of coronary microvessels to adenosine A2A receptor activation appears to be independent of cAMP signaling.
...
PMID:Functional and molecular characterization of receptor subtypes mediating coronary microvascular dilation to adenosine. 1116 32
Adenosine protects the myocardium of the heart by exerting an antiadrenergic action via the
adenosine A1 receptor
(A1R). Because beta 1-adrenergic receptor (beta 1R) stimulation elicits myocardial protein phosphorylation, the present study investigated whether
protein kinase A
(
PKA
) catalyzed rat heart ventricular membrane phosphorylation affects the beta 1R adrenergic and A1R adenosinergic actions on adenylyl cyclase activity. Membranes were either phosphorylated with
PKA
in the absence/presence of a protein kinase inhibitor (PKI) or dephosphorylated with alkaline phosphatase (AP) and assayed for adenylyl cyclase activity (AC) in the presence of the beta 1R agonist isoproterenol (ISO) and/or the A1R agonist 2-chloro-N6-cyclopentyladenosine (CCPA). 32P incorporation into the protein substrates of 140-120, 43, and 29 kDa with
PKA
increased both the ISO-elicited activation of AC by 51-54% and the A1R-mediated reduction of the ISO-induced increase in AC by 29-50%, thereby yielding a total antiadrenergic effect of approximately 78%. These effects of
PKA
were prevented by PKI. AP reduced the ISO-induced increase in AC and eliminated the antiadrenergic effect of CCPA. Immunoprecipitation of the solubilized membrane adenylyl cyclase with the use of a polyclonal adenylyl cyclase VI antibody indicated that the enzyme is phosphorylated by
PKA
. These results indicate that the cardioprotective effect of adenosine afforded by its antiadrenergic action is facilitated by cardiac membrane phosphorylation.
...
PMID:Beta-adrenergic and antiadrenergic modulation of cardiac adenylyl cyclase is influenced by phosphorylation. 1280 16
Vocal behavior in songbirds exemplifies a rich integration of motor, cognitive, and social functions that are shared among vertebrates. As a part of the underlying neural substrate, the song system, the anterior forebrain pathway (AFP) is required for song learning and maintenance. The AFP resembles the mammalian basal ganglia-thalamocortical loop in its macroscopic organization, neuronal intrinsic properties, and microcircuitry. Area X, the first station in the AFP, is a part of the basal ganglia essential for vocal learning. It receives glutamatergic inputs from pallial structures and sends GABAergic outputs to thalamic structures. It also receives dense dopaminergic innervation from the midbrain. The role of this innervation is essentially unknown. Here we provide evidence that dopamine (DA) can modulate the glutamatergic inputs to spiny neurons in area X. In whole-cell voltage-clamp recordings from neurons in brain slices of adult zebra finches, we found that activation of D1-like DA receptors depresses ionotropic glutamatergic synaptic current in area X spiny neurons. This effect is mediated by a presynaptic site of action, mimicked by activation of adenylyl cyclase, and blocked by
protein kinase A
inhibitor and an
adenosine A1 receptor
antagonist. These results suggest that, in addition to altering the input-output function of spiny neurons by modulating their excitability, as we have shown previously, DA can directly influence the excitatory inputs to these neurons as well. Thus, DA can exert fine control over information processing through spiny neurons in area X, the dynamics of the AFP output, and ultimately song learning and maintenance.
...
PMID:Presynaptic depression of glutamatergic synaptic transmission by D1-like dopamine receptor activation in the avian basal ganglia. 1285 27
Adenosine can reduce pain and allodynia in animals and man, probably via spinal adenosine A1 receptors. In the present study, we investigate the distribution of the
adenosine A1 receptor
in the rat spinal cord dorsal horn using immunohistochemistry, in situ hybridization, radioligand binding, and confocal microscopy. In the lumbar cord dorsal horn, dense immunoreactivity was seen in the inner part of lamina II. This was unaltered by dorsal root section or thoracic cord hemisection. Confocal microscopy of the dorsal horn revealed close anatomical relationships but no or only minor overlap between A1 receptors and immunoreactivity for markers associated with primary afferent central endings: calcitonin gene-related peptide, or isolectin B4, or with neuronal subpopulations: mu-opioid receptor, neuronal nitric oxide synthase, met-enkephalin, parvalbumin, or
protein kinase
Cgamma, or with glial cells: glial fibrillary acidic protein. A few
adenosine A1 receptor
positive structures were double-labeled with alpha-amino-3-hydroxy-5-methyl-4-isoaxolepropionic acid glutamate receptor subunits 1 and 2/3. The results indicate that most of the adenosine A1 receptors in the dorsal horn are located in inner lamina II postsynaptic neuronal cell bodies and processes whose functional and neurochemical identity is so far unknown. Many
adenosine A1 receptor
positive structures are in close contact with isolectin B4 positive C-fiber primary afferents and/or postsynaptic structures containing components of importance for the modulation of nociceptive information.
...
PMID:Distribution of antinociceptive adenosine A1 receptors in the spinal cord dorsal horn, and relationship to primary afferents and neuronal subpopulations. 1458 Sep 41
The G(i)-linked
adenosine A1 receptor
has been shown to mediate anti-inflammatory actions, possibly via modulation of the transcription factor nuclear factor-kappaB (NFkappaB). Here we demonstrate that an adenosine A1 agonist, N(6)-cyclohexyladenosine (CHA), activated IKKalpha/beta phosphorylation through PTX-insensitive G proteins in human lymphoblastoma Reh cells. To delineate the mechanism of action, different PTX-insensitive G proteins were expressed in human embryonic kidney 293 cells. Only Galpha(16) supported the CHA-induced IKK phosphorylation and NFkappaB-driven luciferase activity in time-dependent, dose-dependent, and PTX-insensitive manners. Gbetagamma subunits also modulated IKK/NFkappaB, as indicated by the stimulatory actions of Gbeta(1)gamma(2) and the abrogation of CHA-induced response by transducin. The participation of phospholipase Cbeta, protein kinase C, and calmodulin-dependent kinase II in CHA-induced IKK/NFkappaB activation were demonstrated by employing specific inhibitors and dominant-negative mutants. Inhibition of c-Src and numerous intermediates along the extracellular signal-regulated (ERK) kinase cascade including Ras,
Raf-1
kinase, and MEK1/2 abolished the CHA-induced IKK/NFkappaB activation. Although c-Jun N-terminal kinase and p38 MAPK were also activated by CHA, they were not required for the IKK/NFkappaB regulation. Similar results were obtained using Reh cells. These data suggest that the G(16)-mediated activation of IKK/NFkappaB by CHA required a complex signaling network composed of multiple intermediates.
...
PMID:G16-mediated activation of nuclear factor kappaB by the adenosine A1 receptor involves c-Src, protein kinase C, and ERK signaling. 1548 65
We found that caffeine significantly inhibited epidermal growth factor (EGF)- and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell transformation in the JB6 mouse epidermal cell line. The tumor promoter-induced cell transformation was also blocked by treatment with an
adenosine A1 receptor
antagonist, 8-phenyltheophylline (8-PTH). Caffeine slightly attenuated activation of EGF-induced activator protein 1 (AP-1) activation, which play important roles in cell transformation, but only at the highest concentration examined (1 mM). Interestingly, pretreatment with caffeine suppressed EGF-induced phosphorylation and activation of Akt and ribosomal p 70 S6
protein kinase
(p 70 S 6 K), a target of Akt, without inhibiting phosphatidylinositol 3-kinase (PI 3 K) activation. The inhibition of Akt activation of caffeine was not a result of its adenosine receptor antagonism. Because Akt plays a key role in signal transduction pathways leading to cell proliferation and apoptosis, our results provide novel insight into possible mechanisms of the chemotherapeutic effect of caffeine.
...
PMID:Inhibition of epidermal growth factor-induced cell transformation and Akt activation by caffeine. 1604 20
Chemical LTD (CLTD) of synaptic transmission is triggered by simultaneously increasing presynaptic [cGMP] while inhibiting
PKA
. Here, we supply evidence that class II, but not III, metabotropic glutamate receptors (mGluRs), and A1 adenosine receptors, both negatively coupled to adenylate cyclase, play physiologic roles in providing
PKA
inhibition necessary to promote the induction of LTD at Schaffer collateral-CA1 synapses in hippocampal slices. Simultaneous activation of group II mGluRs with the selective agonist (2S,2'R,3'R)-2-(2',3'-dicarboxy-cyclopropyl) glycine (DCGIV; 5 microM), while raising [cGMP] with the type V phosphodiesterase inhibitor, zaprinast (20 microM), resulted in a long-lasting depression of synaptic strength. When zaprinast (20 microM) was combined with a cell-permeant
PKA
inhibitor H-89 (10 microM), the need for mGluR IIs was bypassed. DCGIV, when combined with a "submaximal" low frequency stimulation (1 Hz/400 s), produced a saturating LTD. The mGluR II selective antagonist, (2S)-alpha-ethylglutamic acid (EGLU; 5 microM), blocked induction of LTD by prolonged low frequency stimulation (1 Hz/900 s). In contrast, the mGluR III selective receptor blocker, (RS)-a-Cyclopropyl-[3- 3H]-4-phosphonophenylglycine (CPPG; 10 microM), did not impair LTD. The selective
adenosine A1 receptor
antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; 100 nM), also blocked induction of LTD, while the
adenosine A1 receptor
agonist N6-cyclohexyl adenosine (CHA; 50 nM) significantly enhanced the magnitude of LTD induced by submaximal LFS and, when paired with zaprinast (20 microM), was sufficient to elicit CLTD. Inhibition of
PKA
with H-89 rescued the expression of LTD in the presence of either EGLU or DPCPX, confirming the hypothesis that both group II mGluRs and A1 adenosine receptors enhance the induction of LTD by inhibiting adenylate cyclase and reducing
PKA
activity.
...
PMID:Activation of receptors negatively coupled to adenylate cyclase is required for induction of long-term synaptic depression at Schaffer collateral-CA1 synapses. 1632 19
Modern therapeutic methods for manipulation of gene expression in allergic diseases have been receiving increased attention in the emerging era of functional genomics. With the growing application of gene silencing technologies, pharmacological modulation of translation represents a great advance in molecular therapy for allergy. Several strategies for sequence-specific post-transcriptional inhibition of gene expression can be distinguished: antisense oligonucleotides (AS-ONs), ribozymes (RZs), DNA enzymes (DNAzymes), and RNA interference (RNAi) triggered by small interfering RNAs (siRNAs). Potential anti-mRNA drugs in asthma and other allergic disorders may be targeted to cell surface receptors (
adenosine A1 receptor
, high-affinity receptor Fc-epsilon RI-alpha, cytokine receptors), adhesion molecules and ligands (ICAM-1, VLA-4), ion channels (calcium-dependent chloride channel-1), cytokines and related factors (IL-4, IL-5, IL-13, SCF, TNF-alpha, TGF-beta1), intracellular signal transduction molecules, such as tyrosine-protein kinases (Syk, Lyn, Btk), serine/ threonine-protein kinases (p38 alpha MAPkinase,
Raf-1
), non-kinase signaling proteins (RasGRP4), and transcription factors involved in Th2 differentiation and allergic inflammation (STAT-6, GATA-3, NF-kappaB). The challenge to scientists is to determine which of the candidate targets warrants investment of time and resources. New-generation respirable AS-ONs, external guide sequence ribozymes, and RNA interference-based therapies have the potential to satisfy unmet needs in allergy treatment, acting at a more proximal level to a key etiopathogenetic molecular process, represented by abnormal expression of genes. Moreover, antisense and siRNA technologies imply a more rational design of new drugs for allergy.
...
PMID:Antisense- and RNA interference-based therapeutic strategies in allergy. 1636 94
We used the patch-clamp technique to examine the effect of adenosine on the basolateral K channels in the thick ascending limb (TAL) of the rat kidney. A 50-pS inwardly rectifying K channel was detected in the basolateral membrane, and the channel activity was decreased by hyperpolarization. Application of adenosine (10 microM) increased the activity of basolateral 50 pS K channels, defined by NP(o), from 0.21 to 0.41. The effect of adenosine on the 50 pS K channels was mimicked by cyclohexyladenosine (CHA), which increased channel activity by a dose-dependent manner. However, inhibition of the
A1 adenosine receptor
with 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX) failed to block the effect of CHA. In contrast, application of 8-(3-chlorostyryl) caffeine (CSC), an A2 adenosine antagonist, abolished the stimulatory effect of CHA. The possibility that the effect of adenosine and adenosine analog on the basolateral 50 pS K channel was the result of activation of the A2 adenosine receptor was also suggested by the observation that application of CGS-21680, a selected A(2A) adenosine receptor agonist, increased the channel activity. Also, inhibition of
PKA
with N-[2-(methylamino)ethyl]-5-isoquinoline sulfonamide-2HC1 abolished the stimulatory effect of CHA on the basolateral 50 pS K channel. Moreover, addition of the membrane-permeable cAMP analog increases the activity of 50 pS K channels. We conclude that adenosine activates the 50 pS K channel in the basolateral membrane of the TAL and the stimulatory effect is mainly mediated by a
PKA
-dependent pathway via the A2 adenosine receptor in the TAL.
...
PMID:Adenosine stimulates the basolateral 50 pS K channels in the thick ascending limb of the rat kidney. 1747 99
Poliovirus (PV) and enterovirus 71 (EV71) cause severe neurological symptoms in their infections of the central nervous system. To identify compounds with anti-PV and anti-EV71 activities that would not allow the emergence of resistant mutants, we performed drug screening by utilizing a pharmacologically active compound library targeting cellular factors with PV and EV71 pseudoviruses that encapsidated luciferase-encoding replicons. We have found that metrifudil (N-[2-methylphenyl]methyl)-adenosine) (an A2 adenosine receptor agonist), N(6)-benzyladenosine (an
A1 adenosine receptor
agonist) and NF449 (4,4',4'',4'''-[carbonylbis[imino-5,1,3-benzenetriyl bis(carbonyl-imino)]] tetrakis (benzene-1,3-disulfonic acid) octasodium salt) (a Gs-alpha inhibitor) have anti-EV71 activity, and that GW5074 (3-(3, 5-dibromo-4-hydroxybenzylidine-5-iodo-1,3-dihydro-indol-2-one)) (a
Raf-1
inhibitor) has both anti-PV and anti-EV71 activities. EV71 mutants resistant to metrifudil, N(6)-benzyladenosine and NF449 were isolated after passages in the presence of these compounds, but mutants resistant to GW5074 were not isolated for both PV and EV71. The inhibitory effect of GW5074 was not observed in Sendai virus infection and the treatment did not induce the expression of OAS1 and STAT1 mRNA. Small interfering RNA treatment against putative cellular targets of GW5074, including
Raf-1
, B-Raf, Pim-1, -2, and -3,
HIPK2
, GAK, MST2 and ATF-3, did not consistently suppress PV replication. Moreover, downregulation of
Raf-1
and B-Raf did not affect the sensitivity of RD cells to the inhibitory effect of GW5074. These results suggest that GW5074 has strong and selective inhibitory effect against the replication of PV and EV71 by inhibiting conserved targets in the infection independently of the interferon response.
...
PMID:Characterization of pharmacologically active compounds that inhibit poliovirus and enterovirus 71 infectivity. 1879 21
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