Calcium Ion Stimulated Endogenous Protein Kinase Catalyzed Phosphorylation of Peripheral and Central Nerve Myelin Proteins: Comparison between Normal and Genetically Dystrophic Mouse

Enzyme ◽  
1980 ◽  
Vol 25 (2) ◽  
pp. 102-105 ◽  
Author(s):  
Elena H. Petroli ◽  
Prakash V. Sulakhe
Keyword(s):  
Protein Kinase ◽  
Calcium Ion ◽  
Myelin Proteins ◽  
Dystrophic Mouse ◽  
Endogenous Protein

Calcium ion stimulated endogenous protein kinase catalyzed phosphorylation of peripheral nerve myelin proteins

1979 ◽  
Vol 57 (10) ◽  
pp. 1200-1204 ◽  
Author(s):  
Elena H. Petrali ◽  
Prakash V. Sulakhe
Keyword(s):  
Protein Kinase ◽  
Cauda Equina ◽  
Fold Increase ◽  
Myelin Proteins ◽  
Dependent Protein Kinase ◽  
Maximal Stimulation ◽  
Endogenous Protein ◽  
Dependent Protein ◽  
Triton X ◽  
Significant Stimulatory Effect

Myelin isolated from the rat peripheral nervous system (sciatic nerve and cauda equina) contained Mg2+-dependent protein kinase that phosphorylated myelin polypeptides. Ca2+, in micromolar concentrations, markedly stimulated phosphorylation (half-maximal stimulation at 5 μM (free) Ca2+) but at higher concentrations (> 100 μM Ca2+) it caused inhibition. In the presence of Triton X-100, phosphorylation (±Ca2+) of myelin was increased and Ca2+ caused up to a 10-fold increase in phosphorylation. Among the myelin polypeptides, P0 (Mr, 28 000), a major glycoprotein, accounted for nearly 60% of the total phosphate incorporated into the myelin and Ca2+ markedly promoted phosphorylation of P0. Phosphorylation of other myelin polypeptides, P2 (Mr, 16 000), Y (Mr, 26 000), and P1 (Mr, 20 000), and the Ca2+-stimulatory effect on phosphorylation of these were also evident. Cyclic AMP (or other cyclic nucleotides) failed to show any significant stimulatory effect on myelin phosphorylation.

scholarly journals Calcium ion-stimulated phosphorylation of myelin proteins

1980 ◽  
Vol 186 (2) ◽  
pp. 469-473 ◽  
Author(s):  
P V Sulakhe ◽  
E H Petrali ◽  
B J Thiessen ◽  
E R Davis
Keyword(s):  
Nervous System ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Peripheral Nervous System ◽  
Calcium Ion ◽  
Myelin Proteins ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Specific Proteins

Myelin isolated from the central and peripheral nervous system contains a Mg2+-dependent protein kinase that catalyses phosphorylation of myelin-specific proteins. This phosphorylation is markedly stimulated by Ca2+ but not by cyclic AMP. Evidence was obtained that suggested an involvement of calmodulin-like protein in the stimulatory effects of Ca2+ on myelin phosphorylation.

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.

scholarly journals The Kinase Specificity of Protein Kinase Inhibitor Peptide

2021 ◽  
Vol 12 ◽  
Author(s):  
Yao Chen ◽  
Bernardo L. Sabatini
Keyword(s):  
Protein Kinase ◽  
Kinase Inhibitor ◽  
Protein Kinase Inhibitor ◽  
Temporal Specificity ◽  
Kinase C ◽  
Endogenous Protein ◽  
Inhibitor Peptide ◽  
Kinase Specificity ◽  
G Protein Coupled

G-protein-coupled-receptor (GPCR) signaling is exquisitely controlled to achieve spatial and temporal specificity. The endogenous protein kinase inhibitor peptide (PKI) confines the spatial and temporal spread of the activity of protein kinase A (PKA), which integrates inputs from three major types of GPCRs. Despite its wide usage as a pharmaceutical inhibitor of PKA, it was unclear whether PKI only inhibits PKA activity. Here, the effects of PKI on 55 mouse kinases were tested in in vitro assays. We found that in addition to inhibiting PKA activity, both PKI (6–22) amide and full-length PKIα facilitated the activation of multiple isoforms of protein kinase C (PKC), albeit at much higher concentrations than necessary to inhibit PKA. Thus, our results call for appropriate interpretation of experimental results using PKI as a pharmaceutical agent. Furthermore, our study lays the foundation to explore the potential functions of PKI in regulating PKC activity and in coordinating PKC and PKA activities.

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