Endogenous protein phosphorylation and protein kinase activity in winged bean

1997 ◽  
Vol 46 (3) ◽  
pp. 455-459 ◽  
Author(s):  
Kakoli Mukhopadhyay ◽  
Manoranjan Singh
Keyword(s):  
Protein Kinase ◽  
Protein Phosphorylation ◽  
Kinase Activity ◽  
Winged Bean ◽  
Protein Kinase Activity ◽  
Endogenous Protein

Effect of Thrombin on Phosphorylation of Platelet Membrane Proteins

1976 ◽  
Vol 35 (03) ◽  
pp. 635-642 ◽  
Author(s):  
M Steiner
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Qualitative Change ◽  
Protein Kinase Activity ◽  
Protein Substrates ◽  
Phosphoprotein Phosphatase ◽  
Progressive Loss ◽  
Platelet Membranes ◽  
Endogenous Protein ◽  
Considerable Loss

SummaryThe effect of thrombin on the phosphorylating activity of platelet membranes was compared to that of trypsin. Preincubation of non-32P phosphorylated platelet membranes with or without either of these two enzymes resulted in a considerable loss of membrane protein kinase activity which was most severe when trypsin was used. Protein kinase activity and endogenous protein acceptors decreased in parallel. 32P-phosphorylated membranes showed a slow but progressive loss of label which was accelerated by trypsin. Thrombin under these conditions prevented the loss of 32P-phosphate. These results are interpreted to indicate a thrombin-induced destruction of a phosphoprotein phosphatase. The protein kinase activity of phosphorylated platelet membranes using endogenous or exogenous protein substrates showed a significant reduction compared to non-phosphorylated membranes suggesting a deactivation of protein kinase by phosphorylation of platelet membranes. Neither thrombin nor trypsin caused a qualitative change in the membrane polypeptides accepting 32P-phosphate but resulted in quantitative alterations of their ability to become phosphorylated.

Stimulation of calcium accumulation in cardiac sarcolemma by protein kinase

1976 ◽  
Vol 54 (5) ◽  
pp. 438-445 ◽  
Author(s):  
Prakash V. Sulakhe ◽  
Nicholas Ling-Kit Leung ◽  
Patrick J. St. Louis
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Cardiac Sarcolemma ◽  
Guinea Pig Heart ◽  
Calcium Accumulation ◽  
Exogenous Protein ◽  
Endogenous Protein ◽  
Membrane Phosphorylation

Sarcolemmal membranes isolated from guinea pig heart ventricles contained an ATP-dependent calcium-sequestering activity. Sarcolemmai calcium accumulation but not binding was enhanced by preincubation of membranes with exogenous protein kinase, with cyclic AMP, or with isoproterenol. Protein kinase (EC 2.7.1.37) increased the V of Ca2+ accumulation by sarcolemma without any significant effect on the affinity for Ca2+. The endogenous protein kinase activity present in isolated sarcolemma affected membrane phosphorylation. Cyclic AMP increased the endogenous kinase activity modestly, whereas histone increased it significantly. Exogenous protein kinase also catalyzed phosphorylation of these membranes. Endogenous and exogenous kinase-catalyzed phosphorylation of sarcolemma was hydroxylamine-insensitive. Ca2+-dependent ATPase (EC 3.6.1.3) (extra ATPase) activity of sarcolemma was also increased by protein kinase.

Phosphorylation-dependent modulation of cardiac calcium current by intracellular free magnesium

2001 ◽  
Vol 281 (4) ◽  
pp. H1532-H1544 ◽  
Author(s):  
Siegried Pelzer ◽  
Chicuong La ◽  
Dieter J. Pelzer
Keyword(s):  
Protein Kinase ◽  
Protein Phosphorylation ◽  
Calcium Current ◽  
Kinase Activity ◽  
Kinase Inhibitor ◽  
Protein Kinase Activity ◽  
Inhibitory Effects ◽  
Maximal Stimulation ◽  
Free Magnesium ◽  
Stimulation Of

We compared the effects of cytosolic free magnesium (Mg[Formula: see text]) on L-type Ca2+ current ( I Ca,L) in patch-clamped guinea pig ventricular cardiomyocytes under basal conditions, after inhibition of protein phosphorylation, and after stimulation of cAMP-mediated phosphorylation. Basal I Ca,L density displayed a bimodal dependence on the concentration of Mg[Formula: see text]([Mg2+]i; 10−6–10−2 M), which changed significantly as cell dialysis progressed due to a pronounced and long-lasting rundown of I Ca,L in low-Mg2+ dialysates. Ten minutes after patch breakthrough, I Ca,L density (at +10 mV) in Mg[Formula: see text]-depleted cells ([Mg2+]i∼1 μM) was elevated, increased to a maximum at ∼20 μM [Mg2+]i, and declined steeply at higher [Mg2+]i. Treatment with the broad-spectrum protein kinase inhibitor K252a (10 μM) reduced I Ca,L density and abolished these effects of Mg[Formula: see text] except for a negative shift of I Ca,L-voltage relations with increasing [Mg2+]i. Maximal stimulation of cAMP-mediated phosphorylation occluded the Mg[Formula: see text]-induced stimulation of I Ca,L and prevented inhibitory effects of the ion at [Mg2+]i <1 mM but not at higher concentrations. These results show that the modulation of I Ca,L by Mg[Formula: see text] requires protein kinase activity and likely originates from interactions of the ion with proteins involved in the regulation of protein phosphorylation/dephosphorylation. Stimulatory effects of Mg[Formula: see text] on I Ca,L seem to increase the cAMP-mediated phosphorylation of Ca2+ channels, whereas inhibitory effects of Mg[Formula: see text] appear to curtail and/or reverse cAMP-mediated phosphorylation.

Quantitative analysis of protein phosphorylation status and protein kinase activity on microarrays using a novel fluorescent phosphorylation sensor dye

PROTEOMICS ◽  
2003 ◽  
Vol 3 (7) ◽  
pp. 1244-1255 ◽  
Author(s):  
Karen Martin ◽  
Thomas H. Steinberg ◽  
Laurie A. Cooley ◽  
Kyle R. Gee ◽  
Joseph M. Beechem ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Protein Kinase ◽  
Protein Phosphorylation ◽  
Kinase Activity ◽  
Protein Kinase Activity
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