Endogenous protein kinase inhibitor levels regulate changes in specific activity of protein kinase in quiescent cells stimulated to proliferate

1977 ◽  
Vol 78 (4) ◽  
pp. 1311-1318 ◽  
Author(s):  
Max Costa
Keyword(s):  
Protein Kinase ◽  
Kinase Inhibitor ◽  
Specific Activity ◽  
Protein Kinase Inhibitor ◽  
Quiescent Cells ◽  
Endogenous Protein

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.

scholarly journals The kinase specificity of protein kinase inhibitor peptide (PKI)

2020 ◽  
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

AbstractG-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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