cAMP Signaling (camp + signaling)

Distribution by Scientific Domains
Life Sciences60%

Terms modified by cAMP Signaling

  • camp signaling pathway
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    Selected Abstracts

    Genetic Correlations Between Initial Sensitivity to Ethanol and Brain cAMP Signaling in Inbred and Selectively Bred Mice

    ALCOHOLISM, Issue 6 2001
    Shelli L. Kirstein
    Background: Several lines of evidence have suggested a role for cAMP (adenosine 3,,5,-cyclic monophosphate) signaling in the acute and chronic effects of ethanol. This study investigated whether there is a genetic correlation between cAMP synthesis in the brain and the acute effects of ethanol [alcohol sensitivity or acute functional tolerance (AFT)]. Methods: By using nine inbred strains of mice, we measured initial sensitivity and AFT to ethanol with a test of balance on a dowel. Initial sensitivity was defined by the blood ethanol concentration (BEC0) at the loss of balance on a dowel after an ethanol injection [1.75 g/kg intraperitoneally (ip)]. When mice were able to regain balance on the dowel, BEC1 was determined, and a second ethanol injection was given (2 g/kg ip). Upon final regaining of balance, BEC2 was determined. AFT was defined by the difference between BEC1 and BEC2 (AFT =,BEC = BEC2, BEC1). Cyclic AMP synthesis was measured in whole-cell preparations in the cerebellum and other brain areas of mice of the nine inbred strains. Results: Significant differences in BEC0 and AFT were seen among the mice of the nine inbred strains. Cerebellar basal and forskolin- and isoproterenol-stimulated cAMP production differed significantly between the strains, and BEC0 was found to correlate significantly with forskolin- and isoproterenol-stimulated cAMP accumulation in the cerebellum (r= 0.70 and 0.94, respectively). When we measured cAMP production in mesencephalic and telencephalic tissue in three strains of mice that differed significantly in isoproterenol-stimulated cAMP accumulation in the cerebellum, significant differences between strains were found only in telencephalic tissue. The relative relationship between the rank order of the three strains for cAMP accumulation in the telencephalon and initial sensitivity to ethanol was identical to that seen with the cerebellum. However, AFT did not correlate with cAMP accumulation in the cerebellum or any other brain area tested. Conclusions: These results suggest that cAMP-generating systems of the cerebellum and possibly the brain areas contained in telencephalic tissues (e.g., basal ganglia) may have an important relationship to an animal's initial sensitivity to the incoordinating effects of ethanol. [source]

    A Phytochrome-like Protein AphC Triggers the cAMP Signaling Induced by Far-red Light in the Cyanobacterium Anabaena sp.

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2004
    Strain PCC7120
    ABSTRACT In the filamentous, nitrogen-fixing cyanobacterium Anabaena sp. PCC7120, red light (630 nm) decreased, whereas far-red light (720 nm) increased cellular adenosine 3,,5,-cyclic monophosphate (cAMP) content. To find a red and far-red light photoreceptor that triggers the cAMP signal cascade, we disrupted 10 open reading frame having putative chromophore-binding GAF domains. The response of the cellluar cAMP concentration to red and far-red light in each open reading frame disruptant was determined. It was found that only the mutant of the gene all2699 failed to respond to far-red light. The open reading frame named as aphC encoded a protein with 920 amino acids including GAF domains similar to those involved in Cph2, a photoreceptor of Synechocystis sp. PCC6803. To determine which adenylate cyclase (AC) is responsible for far-red light signal, we disrupted all AC genes and found that CyaC was the candidate. The enzymatic activity of CyaC might be controlled by a far-red light photoreceptor through the phosphotransfer reaction. The site-specific mutant of the Asp59 residue of the receiver (R1) domain of CyaC lost its light-response capability. It was suggested that the far-red light signal was received by AphC and then transferred to the N-terminal response regulator domain of CyaC. Then its catalytic activity was stimulated, which increased the cellular cAMP concentration and drove the subsequent signal transduction cascade. [source]

    Cross-talk between olfactory second messenger pathways

    FEBS JOURNAL, Issue 14 2000
    Alexander Vogl
    The second messengers 3,-5,-cyclic-monophosphate (cAMP) and inositol 1,4,5-trisphosphate (InsP3) have been implicated in olfactory signal transduction in various species. The results of the present study provide evidence that the two olfactory second messenger pathways in rat olfactory neurons do not work independently but rather show a functional antagonism: whereas inhibition of phospholipase C (PLC) in isolated olfactory cilia by U-73122 led to an augmentation of odor-induced cAMP signaling, activation of the phosphoinositol pathway resulted in attenuation of odor-induced cAMP formation. Furthermore, this study indicates that elevated cAMP levels cause suppression of odor-induced InsP3 signaling, whereas inhibition of adenylate cyclase (AC) by cisN -(2-phenylcyclopentyl)azacylotridec-1-en-2-amine (MDL-12,330 A) results in potentiation of odor-induced InsP3 formation. Concerning the molecular mechanism involved in cross-interaction, the experimental data indicate that the observed antagonism of elevated cAMP is based on inhibition of PLC activation rather than on stimulation of InsP3 degradation. As blockage of the endogenous protein kinase A (PKA) prevented the inhibitory effect of cAMP, the suppression of odor-induced InsP3 signaling by cAMP may be mediated by a PKA-controlled reaction. [source]

    PML/RAR, fusion protein mediates the unique sensitivity to arsenic cytotoxicity in acute promyelocytic leukemia cells: Mechanisms involve the impairment of cAMP signaling and the aberrant regulation of NADPH oxidase,

    JOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2008
    Lingna Li
    Acute promyelocytic leukemia (APL) cells are characterized by PML/RAR, fusion protein, high responsiveness to arsenic trioxide (ATO)-induced cytotoxicity and an abundant generation of reactive oxygen species (ROS). In this study we investigated the association among these three features in APL-derived NB4 cells. We found that NADPH oxidase-derived ROS generation was more abundant in NB4 cells compared with monocytic leukemia U937 cells. By using PR9, a sub-line of U937 stably transduced with the inducible PML/RAR, expression vectors, we attributed disparities on ROS generation and ATO sensitivity to the occurrence of PML/RAR, fusion protein, since PML/RAR,-expressing cells appeared higher NADPH oxidase activity, higher ROS level and higher sensitivity to ATO. On the other hand, the basal intensity of cAMP signaling pathway was compared between NB4 and U937 as well as between PR9 cells with or without PML/RAR,, demonstrating that PML/RAR,-expressing cells had an impaired cAMP signaling pathway which relieved its inhibitory effect on NADPH oxidase derived ROS generation. In summary, the present study demonstrated the correlation of PML/RAR, with cAMP signaling pathway, NADPH oxidase and ROS generation in APL cells. PML/RAR, that bestows NB4 cells various pathological features, paradoxically also endows these cells with the basis for susceptibility to ATO-induced cytotoxcity. J. Cell. Physiol. 217: 486,493, 2008. © 2008 Wiley-Liss, Inc. [source]

    Regulation of protein phosphatase 1, activity in hypoxia through increased interaction with NIPP1: Implications for cellular metabolism

    JOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2006
    Kathrina M. Comerford
    Eukaryotic cells sense decreased oxygen levels and respond by altering their metabolic strategy to sustain non-respiratory ATP production through glycolysis, and thus promote cell survival in a hypoxic environment. Protein phosphatase 1 (PP1) has been recently implicated in the governance of the rational use of energy when metabolic substrates are abundant and contributes to cellular recovery following metabolic stress. Under conditions of hypoxia, the expression of the gamma isoform of PP1 (PP1,), is diminished, an event we have hypothesized to be involved in the adaptive cellular response to hypoxia. Decreased PP1, activity in hypoxia has a profound impact on the activity of the cAMP response element binding protein (CREB), a major transcriptional regulator of metabolic genes and processes. Here, we demonstrate a further mechanism leading to inhibition of PP1 activity in hypoxia which occurs at least in part through increased association with the nuclear inhibitor of PP1 (NIPP1), an event dependent upon decreased basal cAMP/PKA-dependent signaling. Using a dominant negative NIPP1 construct, we provide evidence that NIPP1 plays a major role in the regulation of both CREB protein expression and CREB-dependent transcription in hypoxia. Furthermore, we demonstrate functional sequellae of such events including altered gene expression and recovery of cellular ATP levels. In summary, we demonstrate that interaction with NIPP1 mediates decreased PP1, activity in hypoxia, an event which may constitute an inherent part of the cellular oxygen-sensing machinery and may play a role in physiologic adaptation to hypoxia. J. Cell. Physiol. 209: 211,218, 2006. © 2006 Wiley-Liss, Inc. [source]