scholarly journals Elucidating the Mechanism of Recognition and Binding of Protein Kinase Inhibitor by Protein Kinase a using NMR and Fluorescence Spectroscopy

2016 ◽  
Vol 110 (3) ◽  
pp. 558a
Author(s):  
Geoffrey Li ◽  
Cristina Olivieri ◽  
Matthew Neibergall ◽  
Jonggul Kim ◽  
Susan Taylor ◽  
...  
2020 ◽  
Vol 11 ◽  
Author(s):  
Chong Liu ◽  
Ping Ke ◽  
Jingjing Zhang ◽  
Xiaoying Zhang ◽  
Xiongwen Chen

The protein kinase enzyme family plays a pivotal role in almost every aspect of cellular function, including cellular metabolism, division, proliferation, transcription, movement, and survival. Protein kinase A (PKA), whose activation is triggered by cyclic adenosine monophosphate (cAMP), is widely distributed in various systems and tissues throughout the body and highly related to pathogenesis and progression of various kinds of diseases. The inhibition of PKA activation is essential for the study of PKA functions. Protein kinase inhibitor peptide (PKI) is a potent, heat-stable, and specific PKA inhibitor. It has been demonstrated that PKI can block PKA-mediated phosphorylase activation. Since then, researchers have a lot of knowledge about PKI. PKI is considered to be the most effective and specific method to inhibit PKA and is widely used in related research. In this review, we will first introduce the knowledge on the activation of PKA and mechanisms related on the inhibitory effects of PKI on PKA. Then, we will compare PKI-mediated PKA inhibition vs. several popular methods of PKA inhibition.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Cristina Olivieri ◽  
Yingjie Wang ◽  
Geoffrey C Li ◽  
Manu V S ◽  
Jonggul Kim ◽  
...  

In the nucleus, the spatiotemporal regulation of the catalytic subunit of cAMP-dependent protein kinase A (PKA-C) is orchestrated by an intrinsically disordered protein kinase inhibitor, PKI, which recruits the CRM1/RanGTP nuclear exporting complex. How the PKA-C/PKI complex assembles and recognizes CRM1/RanGTP is not well understood. Using NMR, SAXS, fluorescence, metadynamics, and Markov model analysis, we determined the multi-state recognition pathway for PKI. After a fast binding step in which PKA-C selects PKI’s most competent conformations, PKI folds upon binding through a slow conformational rearrangement within the enzyme’s binding pocket. The high-affinity and pseudo-substrate regions of PKI become more structured and the transient interactions with the kinase augment the helical content of the nuclear export sequence, which is then poised to recruit the CRM1/RanGTP complex for nuclear translocation. The multistate binding mechanism featured by PKA-C/PKI complex represents a paradigm on how disordered, ancillary proteins (or protein domains) are able to operate multiple functions such as inhibiting the kinase while recruiting other regulatory proteins for nuclear export.


2014 ◽  
Vol 462 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Zsuzsa Kovacs ◽  
Teresa Schacht ◽  
Ann-Kathrin Herrmann ◽  
Philipp Albrecht ◽  
Konstantinos Lefkimmiatis ◽  
...  

Protein kinase A inhibitor β interacts with the G-protein-coupled zinc receptor GPR39 and increases its cytoprotective constitutive activity via Gα13, but has no effect on ligand-mediated activation of Gs and Gq regardless of its inhibitory activity on protein kinase A.


Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1567 ◽  
Author(s):  
Jascha T. Manschwetus ◽  
George N. Bendzunas ◽  
Ameya J. Limaye ◽  
Matthias J. Knape ◽  
Friedrich W. Herberg ◽  
...  

Kinases regulate multiple and diverse signaling pathways and misregulation is implicated in a multitude of diseases. Although significant efforts have been put forth to develop kinase-specific inhibitors, specificity remains a challenge. As an alternative to catalytic inhibition, allosteric inhibitors can target areas on the surface of an enzyme, thereby providing additional target diversity. Using cAMP-dependent protein kinase A (PKA) as a model system, we sought to develop a hydrocarbon-stapled peptide targeting the pseudosubstrate domain of the kinase. A library of peptides was designed from a Protein Kinase Inhibitor (PKI), a naturally encoded protein that serves as a pseudosubstrate inhibitor for PKA. The binding properties of these peptide analogs were characterized by fluorescence polarization and surface plasmon resonance, and two compounds were identified with KD values in the 500–600 pM range. In kinase activity assays, both compounds demonstrated inhibition with 25–35 nM IC50 values. They were also found to permeate cells and localize within the cytoplasm and inhibited PKA activity within the cellular environment. To the best of our knowledge, these stapled peptide inhibitors represent some of the highest affinity binders reported to date for hydrocarbon stapled peptides.


2000 ◽  
Vol 11 (8) ◽  
pp. 2577-2590 ◽  
Author(s):  
Tina H. Lee ◽  
Adam D. Linstedt

Recent evidence suggests a regulatory connection between cell volume, endoplasmic reticulum (ER) export, and stimulated Golgi-to-ER transport. To investigate the potential role of protein kinases we tested a panel of protein kinase inhibitors for their effect on these steps. One inhibitor, H89, an isoquinolinesulfonamide that is commonly used as a selective protein kinase A inhibitor, blocked both ER export and hypo-osmotic-, brefeldin A-, or nocodazole-induced Golgi-to-ER transport. In contrast, H89 did not block the constitutive ER Golgi-intermediate compartment (ERGIC)-to-ER and Golgi-to-ER traffic that underlies redistribution of ERGIC and Golgi proteins into the ER after ER export arrest. Surprisingly, other protein kinase A inhibitors, KT5720 and H8, as well as a set of protein kinase C inhibitors, had no effect on these transport processes. To test whether H89 might act at the level of either the coatomer protein (COP)I or the COPII coat protein complex we examined the localization of βCOP and Sec13 in H89-treated cells. H89 treatment led to a rapid loss of Sec13-labeled ER export sites but βCOP localization to the Golgi was unaffected. To further investigate the effect of H89 on COPII we developed a COPII recruitment assay with permeabilized cells and found that H89 potently inhibited binding of exogenous Sec13 to ER export sites. This block occurred in the presence of guanosine-5′-O-(3-thio)triphosphate, suggesting that Sec13 recruitment is inhibited at a step independent of the activation of the GTPase Sar1. These results identify a requirement for an H89-sensitive factor(s), potentially a novel protein kinase, in recruitment of COPII to ER export sites, as well as in stimulated but not constitutive Golgi-to-ER transport.


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