Ser16 prevails over Thr17 phospholamban phosphorylation in the β-adrenergic regulation of cardiac relaxation

1999 ◽  
Vol 276 (5) ◽  
pp. H1625-H1633 ◽  
Author(s):  
Meike Kuschel ◽  
Peter Karczewski ◽  
Petra Hempel ◽  
Wolfgang-Peter Schlegel ◽  
Ernst-Georg Krause ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Dependent Protein Kinase ◽  
Adrenergic Regulation ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Dependent Protein ◽  
Cardiac Relaxation ◽  
Main Regulator ◽  
Dose Dependent ◽  
Phospholamban Phosphorylation

Phospholamban is a critical regulator of sarcoplasmic reticulum Ca2+-ATPase and myocardial contractility. To determine the extent of cross signaling between Ca2+ and cAMP pathways, we have investigated the β-adrenergic-induced phosphorylation of Ser16 and Thr17 of phospholamban in perfused rat hearts using antibodies recognizing phospholamban phosphorylated at either position. Isoproterenol caused the dose-dependent phosphorylation of Ser16 and Thr17 with strikingly different half-maximal values (EC50 = 4.5 ± 1.6 and 28.2 ± 1.4 nmol/l, respectively). The phosphorylation of Ser16 induced by isoproterenol, forskolin, or 3-isobutyl-1-methylxanthine correlated to increased cardiac relaxation ( r = 0.96), whereas phosphorylation of Thr17 did not. Elevation of extracellular Ca2+did not induce phosphorylation at Thr17; only in the presence of a submaximal dose of isoproterenol, phosphorylation at Thr17 increased eightfold without additional effects on relaxation rate. Thr17 phosphorylation was partially affected by ryanodine and was completely abolished in the presence of 1 μmol/l verapamil or nifedipine. The data indicate that 1) phosphorylation of phospholamban at Ser16 by cAMP-dependent protein kinase is the main regulator of β-adrenergic-induced cardiac relaxation definitely preceding Thr17 phosphorylation and 2) the β-adrenergic-mediated phosphorylation of Thr17 by Ca2+-calmodulin-dependent protein kinase required influx of Ca2+through the L-type Ca2+ channel.

scholarly journals Anti-phospholamban and protein kinase A alter the Ca2+ sensitivity and maximum velocity of Ca2+ uptake by the cardiac sarcoplasmic reticulum

1998 ◽  
Vol 331 (1) ◽  
pp. 245-249 ◽  
Author(s):  
Margaret E. KARGACIN ◽  
Zenobia ALI ◽  
Gary J. KARGACIN
Keyword(s):  
Protein Kinase ◽  
Sarcoplasmic Reticulum ◽  
Maximum Velocity ◽  
Functional Effect ◽  
Dependent Protein Kinase ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Dependent Protein ◽  
Uptake Velocity ◽  
Phospholamban Phosphorylation ◽  
Kinase A

The activity of the SERCA2a Ca2+ pump in the sarcoplasmic reticulum (SR) of cardiac muscle is inhibited by phospholamban. When phospholamban is phosphorylated by cyclic-AMP-dependent protein kinase (PKA) this inhibition is relieved. It is generally agreed that this results in an increase in the Ca2+ sensitivity of the SR Ca2+ pump; however, some investigators have also reported an increase in the maximum velocity of the pump. We have used a sensitive fluorescence method to measure net Ca2+ uptake by native cardiac SR vesicles and compared the effects of a constitutively active subunit of PKA (cPKA) with those of a monoclonal antibody (A1) that binds to phospholamban and is thought to mimic the effect of phosphorylation. Both the Ca2+ sensitivity and the maximum velocity of uptake were increased by cPKA and by A1. The effects of cPKA and A1 on uptake velocity were only slightly additive. No changes in uptake were detected with denatured cPKA or denatured A1. These results indicate that the functional effect of phospholamban phosphorylation is to increase both the Ca2+ sensitivity and the maximum velocity of net Ca2+ uptake into the SR.

scholarly journals Ca2+ and phospholipid-dependent protein kinase (protein kinase C) activity is not necessarily required for secretion by human neutrophils

Blood ◽  
1986 ◽  
Vol 68 (4) ◽  
pp. 810-817
Author(s):  
KJ Balazovich ◽  
JE Smolen ◽  
LA Boxer
Keyword(s):  
Protein Kinase ◽  
Phorbol Esters ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Soluble Form ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Dose Dependent

Ca2+-dependent and phospholipid-dependent protein kinase (PKC) is a receptor for and is activated by phorbol esters. This enzyme is reportedly involved in the mechanism of superoxide anion (O2-) production and the release of intracellular granule contents from human neutrophils. As previously reported by others, we found that greater than 75% of the total cellular PKC activity existed in a soluble form in untreated neutrophils and that this activity was enhanced in a dose- dependent manner by phorbol 12-myristate 13-acetate (PMA) and by phorbol 12,13-dibutyrate (PDBu). Furthermore, mezerein, an analogue of PMA that is thought to be a competitive inhibitor, did not activate PKC, and on the contrary, inhibited PMA-stimulated activity in a dose- dependent manner. Pretreatment of intact neutrophils with PMA or PDBu caused the “translocation” of PKC activity to the insoluble cell fraction; PKC translocation was not detected after mezerein stimulation at any of the tested concentrations. Neither did mezerein cause an increase in intracellular Ca2+, as monitored by Quin 2 fluorescence. Both phorbol esters and mezerein stimulated intact neutrophils to generate O2- and release lysosomal enzymes into the extracellular medium. Finally sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated key differences in the patterns of endogenous phosphoproteins of neutrophils stimulated with phorbol as compared with mezerein. We therefore suggest that PKC activation may not be the only pathway required to elicit neutrophil responses.

scholarly journals Regulation of prostaglandin synthesis by protein kinase C in mouse peritoneal macrophages

1989 ◽  
Vol 260 (2) ◽  
pp. 471-478 ◽  
Author(s):  
H J Pfannkuche ◽  
V Kaever ◽  
D Gemsa ◽  
K Resch
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Peritoneal Macrophages ◽  
Dependent Manner ◽  
Membrane Phospholipids ◽  
Dependent Protein Kinase ◽  
Kinase C ◽  
Dependent Protein ◽  
Dose Dependent ◽  
Mouse Peritoneal Macrophages

Resident mouse peritoneal macrophages synthesized and released prostaglandins (PGs) when challenged with 12-O-tetradecanoylphorbol 13-acetate (TPA) or 1,2-dioctanoyl-sn-glycerol (DiC8). Both stimuli were found to activate Ca2+/phospholipid-dependent protein kinase C (PKC). 1-(5-Isoquinolinesulphonyl)-2-methylpiperazine (‘H-7’) and D-sphingosine, known to inhibit PKC by different mechanisms, were able to decrease the PKC activity of macrophages in a dose-dependent manner. Addition of either PKC inhibitor decreased PG synthesis and also the release of arachidonic acid (AA) from phospholipids induced by TPA or DiC8. Simultaneously TPA or DiC8 also decreased incorporation of free AA into membrane phospholipids of macrophages. AA incorporation could be restored, however, by pretreatment with the PKC inhibitors. Our results demonstrate an involvement of PKC in the regulation of PG synthesis in mouse peritoneal macrophages and provide further evidence that reacylation of released fatty acids may be an important regulatory step.

Ca2+-Calmodulin-dependent Protein Kinase II Plays a Major Role in Halothane-induced Dose-dependent Relaxation in the Skinned Pulmonary Artery

2002 ◽  
Vol 97 (1) ◽  
pp. 207-214 ◽  
Author(s):  
Judy Y. Su ◽  
Anhkiet C. Vo
Keyword(s):  
Protein Kinase ◽  
Pulmonary Artery ◽  
Initial Increase ◽  
Ionophore A23187 ◽  
Dependent Protein Kinase ◽  
Subsequent Decrease ◽  
Protein Kinase Ii ◽  
Dependent Protein ◽  
Pulmonary Arterial ◽  
Dose Dependent

Background Previously, the authors have shown in Ca(2+)-clamped skinned arterial strips that protein kinase C (PKC) plays a role in 3% halothane- or isoflurane-increased force. PKC in the pulmonary artery and Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) in the femoral artery have been implicated in isoflurane-induced relaxation. For this study, the authors used clinical concentrations of halothane to examine the role of PKC and CaMKII in the halothane-induced biphasic effect on contraction in skinned pulmonary arterial strips. Methods Rabbit pulmonary arterial strips were mounted on force transducers and treated with saponin to make the sarcolemma permeable ("skinning"). Skinned strips were activated by low Ca(2+) (pCa 6.3) buffered with 7 mm EGTA, or the PKC activator phorbol-12,13-dibutyrate (PDBu, 1 microm) until force reached a steady state (control). Halothane (1, 2, and 3%) was administered, and the force was observed at peak and 15 min (test results). Ca(2+) ionophore (A23187, 10 microm) and inhibitors were preincubated in a relaxing solution and present in subsequent contracting solutions. Inhibitors were bisindolylmaleimide and Gö6976 for PKC, and KN-93 and the inhibitor protein (CKIINtide) for CaMKII. Results Halothane (1-3%) dose-dependently caused an initial increase (18-35%) and a subsequent decrease (48-68%) in pCa 6.3-induced force. Bisindolylmaleimide, 3 and 10 microm, completely blocked the increase in force at 2% and 3% halothane, respectively. CKIINtide, 0.1 microm, reduced the force at 3% halothane. The decrease in force at 1% and 2% halothane was partially prevented by 0.01 microm bisindolylmaleimide, and at 1, 2, and 3% halothane by 0.01, 0.1, and 1 microm CKIINtide, respectively. At 3% halothane, the increased force was abolished by A23187. In PDBu-induced force, 3% halothane-induced relaxation was also partially prevented by lower concentrations of KN-93 and CKIINtide. Conclusions In skinned pulmonary arterial strips, the dose-dependent increase in force by halothane is associated with PKC activation, and that of decrease is associated with CaMKII activation.

scholarly journals Nerve growth factor action is mediated by cyclic AMP- and Ca+2/phospholipid-dependent protein kinases.

1986 ◽  
Vol 103 (3) ◽  
pp. 887-893 ◽  
Author(s):  
J Cremins ◽  
J A Wagner ◽  
S Halegoua
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Tyrosine Hydroxylase ◽  
Protein Kinase ◽  
Enzyme Activation ◽  
Dependent Protein Kinase ◽  
Nerve Growth ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Dose Dependent

Nerve growth factor (NGF) mediates the phosphorylation of tyrosine hydroxylase in PC12 cells on two distinct peptide fragments, separable by two-dimensional tryptic phosphopeptide mapping (phosphopeptides T1 and T3). Phorbol diester derivatives capable of activating Ca+2/phospholipid-dependent protein kinase (C-kinase) cause a specific phosphorylation of peptide T3 in a dose-dependent, saturable manner. Derivatives of the endogenous C-kinase activator diacylglycerol, also cause the phosphorylation of tyrosine hydroxylase on peptide T3. The C-kinase inhibitors chlorpromazine and trifluoperazine inhibit the phorbol diester stimulated phosphorylation of site T3 in a dose-dependent manner. These agents inhibit the phosphorylation of T3 in response to NGF, but have no effect on NGF's ability to cause T1 phosphorylation. In a PC12 mutant deficient in cAMP-dependent protein kinase activity, NGF mediates the phosphorylation of tyrosine hydroxylase on peptide T3 but not on T1. We conclude that NGF mediates the activation of both the cAMP-dependent protein kinase and the C-kinase to phosphorylate substrate proteins. These kinases can act independently to phosphorylate tyrosine hydroxylase, each at a different site, and each of which results in the enzyme activation. A molecular framework is thus provided for events underlying NGF action.

Effect of epinephrine or cAMP on cAMP-bound protein kinase holoenzymes in rat heart

1991 ◽  
Vol 260 (3) ◽  
pp. H722-H729
Author(s):  
H. Jiang ◽  
J. D. Corbin
Keyword(s):  
Protein Kinase ◽  
High Performance ◽  
Dissociation Rate ◽  
Free Form ◽  
Type Ii ◽  
Binding Assays ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Dependent Protein ◽  
Peak Fraction

Nonperfused or epinephrine-perfused rat hearts were used to examine the relative amounts of adenosine 3',5'-cyclic monophosphate (cAMP)-free and cAMP-bound holoenzymes of type II cAMP-dependent protein kinase (cAK). Crude tissue extracts of nonperfused hearts were chromatographed in the absence or presence of [3H]cAMP using DEAE-high-performance liquid chromatography. A partially resolved cAMP-free peak of cAK eluted at 0.17 M NaCl, and an asymmetric peak containing bound [3H]cAMP eluted at a slightly higher NaCl concentration. The first peak contained a tetrameric holoenzyme [2 regulatory (R) subunits and 2 catalytic (C) subunits]. From analysis of R-to-C ratios, the [3H]cAMP-bound peak contained a mixture of tetrameric and trimeric (R2C) forms. Both cAMP-free and cAMP-bound holoenzyme forms were virtually inactive without added cAMP under the conditions used. [3H]cAMP dissociation rate studies revealed that the bound cAMP in the peak fraction was equally distributed in the two different binding sites of the enzyme. Compared with the cAMP-free form, the cAMP-bound enzyme in the peak fraction exhibited enhanced binding in nonequilibrium [3H]cAMP binding assays. The cAMP-bound holoenzymes were estimated to represent at least 64% of the total type II cAK in control extracts, and the cAMP-free form was largely converted to the cAMP-bound forms by perfusing hearts with epinephrine.

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