Light-repressible receptor protein kinase: a novel photo-regulated gene from Arabidopsis thaliana

Planta ◽  
1997 ◽  
Vol 202 (4) ◽  
pp. 479-486 ◽  
Author(s):  
Rosalia Deeken ◽  
Ralf Kaldenhoff
2001 ◽  
Vol 359 (3) ◽  
pp. 583-589 ◽  
Author(s):  
Tomas WESTERGREN ◽  
Stephen K. DOVE ◽  
Marianne SOMMARIN ◽  
Christophe PICAL

PtdIns phosphate kinases (PIPkins), which generate PtdInsP2 isomers, have been classified into three subfamilies that differ in their substrate specificities. We demonstrate here that the previously identified AtPIP5K1 gene from Arabidopsis thaliana encodes a PIPkin with dual substrate specificity in vitro, capable of phosphorylating PtdIns3P and PtdIns4P to PtdIns(3,4)P2 and PtdIns(4,5)P2 respectively. We also show that recombinant AtPIP5K1 is phosphorylated by protein kinase A and a soluble protein kinase from A. thaliana. Phosphorylation of AtPIP5K1 by protein kinase A is accompanied by a 40% inhibition of its catalytic activity. Full activity is recovered by treating phosphorylated AtPIP5K1 with alkaline phosphatase.


Oncogene ◽  
2013 ◽  
Vol 32 (50) ◽  
pp. 5574-5581 ◽  
Author(s):  
F Wolff ◽  
A Loipetzberger ◽  
W Gruber ◽  
H Esterbauer ◽  
F Aberger ◽  
...  

2021 ◽  
Author(s):  
Timothy W. Church ◽  
Parul Tewatia ◽  
Saad Hannan ◽  
João Antunes ◽  
Olivia Eriksson ◽  
...  

Interplay between the second messengers cAMP and Ca2+ is a hallmark of dynamic cellular processes. A common motif is the opposition of the Ca2+-sensitive phosphatase calcineurin and the major cAMP receptor, protein kinase A (PKA). Calcineurin dephosphorylates sites primed by PKA to bring about changes including synaptic long-term depression (LTD). AKAP79 supports signaling of this type by anchoring PKA and calcineurin in tandem. In this study, we discovered that AKAP79 increases the rate of calcineurin dephosphorylation of type II PKA regulatory subunits by an order of magnitude. Fluorescent PKA activity reporter assays, supported by kinetic modeling, show how AKAP79-enhanced calcineurin activity enables suppression of PKA without altering cAMP levels by increasing PKA catalytic subunit capture rate. Experiments with hippocampal neurons indicate that this mechanism contributes towards LTD. This non-canonical mode of PKA regulation may underlie many other cellular processes.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Timothy W Church ◽  
Parul Tewatia ◽  
Saad Hannan ◽  
João Antunes ◽  
Olivia Eriksson ◽  
...  

Interplay between the second messengers cAMP and Ca2+ is a hallmark of dynamic cellular processes. A common motif is the opposition of the Ca2+-sensitive phosphatase calcineurin and the major cAMP receptor, protein kinase A (PKA). Calcineurin dephosphorylates sites primed by PKA to bring about changes including synaptic long-term depression (LTD). AKAP79 supports signaling of this type by anchoring PKA and calcineurin in tandem. In this study, we discovered that AKAP79 increases the rate of calcineurin dephosphorylation of type II PKA regulatory subunits by an order of magnitude. Fluorescent PKA activity reporter assays, supported by kinetic modeling, show how AKAP79-enhanced calcineurin activity enables suppression of PKA without altering cAMP levels by increasing PKA catalytic subunit capture rate. Experiments with hippocampal neurons indicate that this mechanism contributes towards LTD. This non-canonical mode of PKA regulation may underlie many other cellular processes.


Endocrinology ◽  
2006 ◽  
Vol 147 (4) ◽  
pp. 1706-1716 ◽  
Author(s):  
Tomomoto Ishikawa ◽  
Patricia L. Morris

In Sertoli epithelial cells, the IL-1β induces prostaglandins (PG) PGE2, PGF2α and PGI2 (7-, 11-, and 2-fold, respectively), but not PGD2, production. Cyclohexamide pretreatment inhibiting protein synthesis prevents IL-1β increases in PG levels, indicating that induction requires de novo protein synthesis. IL-1β-regulated PGE2 and PGF2α production and cytokine expression require activation of cyclooxygenase-2 (COX-2) and c-Jun NH2-terminal kinase, as shown using specific enzyme inhibition. PGE2 and PGF2α stimulate expression of IL-1α, -1β, and -6, findings consistent with PG involvement in IL signaling within the seminiferous tubule. PGE2 and PGF2α reverse COX-2-mediated inhibition of IL-1β induction of cytokine expression and PG production. Sertoli PG receptor expression was determined; four known E-prostanoid receptor (EP) subtypes (1–4) and the F-prostanoid and prostacyclin prostanoid receptors were demonstrated using RNA and protein analyses. Pharmacological characterization of Sertoli PG receptors associated with cytokine regulation was ascertained by quantitative real-time RT-PCR analyses. IL-1β regulates both EP2 mRNA and protein levels, data consistent with a regulatory feedback loop. Butaprost (EP2 agonist) and 11-deoxy PGE1 (EP2 and EP4 agonist) treatments show that EP2 receptor activation stimulates Sertoli cytokine expression. Consistent with EP2-cAMP signaling, protein kinase A inhibition blocks both IL-1β- and PGE2-induced cytokines. Together, the data indicate an autocrine-amplifying loop involving IL-1β-regulated Sertoli function mediated by COX-2-induced PGE2 and PGF2α production. PGE2 activates EP2 and/or EP4 receptor(s) and the protein kinase A-cAMP pathway; PGF2α activates F-prostanoid receptor-protein kinase C signaling. Further identification of the molecular mechanisms subserving these mediators may offer new insights into physiological events as well as proinflammatory-mediated pathogenesis in the testis.


2006 ◽  
Vol 96 (2) ◽  
pp. 591-601 ◽  
Author(s):  
Yasuo Asaumi ◽  
Hiroshi Hasuo ◽  
Takashi Akasu

The lateral septal nucleus receives a diffuse dopaminergic input originating from the ventral tegmental area of the brain stem. We examined whether dopamine (DA) modulates synaptic transmission in the slice preparation of the rat dorsolateral septal nucleus (DLSN). Bath application (10–15 min) of DA (30 μM) markedly depressed the amplitude of fast and slow inhibitory postsynaptic potentials (IPSPs) in DLSN neurons, while it produced only a minor depression of the amplitude of excitatory postsynaptic potentials (EPSPs) obtained in the presence of bicuculline. DA (30 μM) depressed the monosynaptic fast IPSP to ∼50% of control, but did not depress the inward current ( IGABA) induced by exogenous γ-aminobutyric acid (GABA). DA decreased the frequency of miniature fast IPSPs (m-fIPSPs) without significantly changing their amplitude. PD 168077, a selective D4 receptor agonist, depressed the fast and slow IPSPs but not the EPSP and decreased the frequency of m-fIPSPs. Both DA and PD 168077 increased the paired-pulse ratio of the monosynaptic fast IPSP. The inhibitory effect of DA on the fast IPSP was significantly attenuated by L-741,742, an antagonist at D4 receptors, but not by SCH 23390 and sulpiride, a D1-like and a D2-like receptor antagonist, respectively. N-ethylmaleimide, a blocker of pertussis toxin (PTX)-sensitive G protein ( Gi/o), attenuated the DA-induced depression of the fast IPSP. N-[2-((p-bromocinnamyl) amino)ethyl]-5-isoquinoline sulfonamide, a protein kinase A (PKA) inhibitor, attenuated the DA-induced depression of the fast IPSP. These results suggest that DA inhibits spontaneous and evoked release of GABA via the D4 receptor- Gi-protein-PKA system in DLSN neurons.


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