Drugs That Regulate Local Cell Signaling: AKAP Targeting as a Therapeutic Option

2021 ◽  
Vol 61 (1) ◽  
pp. 361-379 ◽  
Author(s):  
Paula J. Bucko ◽  
John D. Scott
Keyword(s):  
Small Molecules ◽  
Therapeutic Option ◽  
Environmental Cues ◽  
Endocrine Disorders ◽  
Dependent Protein Kinase ◽  
Binding Partners ◽  
Phosphoprotein Phosphatases ◽  
Anchoring Proteins ◽  
Dependent Protein ◽  
Local Cell

Cells respond to environmental cues by mobilizing signal transduction cascades that engage protein kinases and phosphoprotein phosphatases. Correct organization of these enzymes in space and time enables the efficient and precise transmission of chemical signals. The cyclic AMP-dependent protein kinase A is compartmentalized through its association with A-kinase anchoring proteins (AKAPs). AKAPs are a family of multivalent scaffolds that constrain signaling enzymes and effectors at subcellular locations to drive essential physiological events. More recently, it has been recognized that defective signaling in certain endocrine disorders and cancers proceeds through pathological AKAP complexes. Consequently, pharmacologically targeting these macromolecular complexes unlocks new therapeutic opportunities for a growing number of clinical indications. This review highlights recent findings on AKAP signaling in disease, particularly in certain cancers, and offers an overview of peptides and small molecules that locally regulate AKAP-binding partners.

scholarly journals Regulation of Ca2+/Calmodulin-Dependent Protein Kinase II Signaling within Hippocampal Glutamatergic Postsynapses during Flurazepam Withdrawal

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Damien E. Earl ◽  
Paromita Das ◽  
William T. Gunning ◽  
Elizabeth I. Tietz
Keyword(s):  
Protein Kinase ◽  
Drug Withdrawal ◽  
Stratum Radiatum ◽  
Immunogold Electron Microscopy ◽  
Dependent Protein Kinase ◽  
Ca1 Neurons ◽  
Binding Partners ◽  
Protein Kinase Ii ◽  
Dependent Protein ◽  
Benzodiazepine Withdrawal

Cessation of one-week oral administration of the benzodiazepine flurazepam (FZP) to rats results in withdrawal anxiety after 1 day of withdrawal. FZP withdrawal is correlated with synaptic incorporation of homomeric GluA1-containingα-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) in the proximal stratum radiatum of CA1 neurons. After 2 days of withdrawal,Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylates GluA1 subunits atSer831, increasing channel conductance. Secondary to AMPAR potentiation, GluN2B-containing N-methyl-D-aspartate receptors (NMDARs), known binding partners of CaMKII, are selectively removed from the postsynaptic density (PSD). While activation of synaptic CaMKII is known to involve translocation to the PSD, CaMKII bound to NMDARs may be removed from the PSD. To distinguish these possibilities, the current studies used postembedding immunogold electron microscopy to investigate alterations in CaMKII signaling at CA1 stratum radiatum synapses after 2 days of FZP withdrawal. These studies revealed decreased total, but not autophosphorylated (Thr286) CaMKIIαexpression in CA1 PSDs. The removal of CaMKII-GluN2B complexes from the PSD during drug withdrawal may serve as a homeostatic mechanism to limit AMPAR-mediated CA1 neuron hyperexcitability and benzodiazepine withdrawal anxiety.

scholarly journals Subcellular Localization and Biological Actions of Activated RSK1 Are Determined by Its Interactions with Subunits of Cyclic AMP-Dependent Protein Kinase

2006 ◽  
Vol 26 (12) ◽  
pp. 4586-4600 ◽  
Author(s):  
Deepti Chaturvedi ◽  
Helen M. Poppleton ◽  
Teresa Stringfield ◽  
Ann Barbier ◽  
Tarun B. Patel
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Nuclear Accumulation ◽  
Regulatory Subunit ◽  
Type I ◽  
Dependent Protein Kinase ◽  
Anchoring Proteins ◽  
Dependent Protein ◽  
Ribosomal S6 Kinase ◽  
Biological Actions

ABSTRACT Cyclic AMP (cAMP)-dependent protein kinase (PKA) and ribosomal S6 kinase 1 (RSK1) share several cellular proteins as substrates. However, to date no other similarities between the two kinases or interactions between them have been reported. Here, we describe novel interactions between subunits of PKA and RSK1 that are dependent upon the activation state of RSK1 and determine its subcellular distribution and biological actions. Inactive RSK1 interacts with the type I regulatory subunit (RI) of PKA. Conversely, active RSK1 interacts with the catalytic subunit of PKA (PKAc). Binding of RSK1 to RI decreases the interactions between RI and PKAc, while the binding of active RSK1 to PKAc increases interactions between PKAc and RI and decreases the ability of cAMP to stimulate PKA. The RSK1/PKA subunit interactions ensure the colocalization of RSK1 with A-kinase PKA anchoring proteins (AKAPs). Disruption of the interactions between PKA and AKAPs decreases the nuclear accumulation of active RSK1 and, thus, increases its cytosolic content. This subcellular redistribution of active RSK1 is manifested by increased phosphorylation of its cytosolic substrates tuberous sclerosis complex 2 and BAD by epidermal growth factor along with decreased cellular apoptosis.

scholarly journals Fyn Regulates Binding Partners of Cyclic-AMP Dependent Protein Kinase A

Proteomes ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 37
Author(s):  
Anna Schmoker ◽  
Samuel Barritt ◽  
Marion Weir ◽  
Jacqueline Mann ◽  
Tyler Hogan ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Quantitative Mass Spectrometry ◽  
Serine Threonine Kinase ◽  
Dependent Protein Kinase ◽  
Threonine Kinase ◽  
Cellular Processes ◽  
Binding Partners ◽  
Dependent Protein ◽  
Kinase A

The cAMP-dependent protein kinase A (PKA) is a serine/threonine kinase involved in many fundamental cellular processes, including migration and proliferation. Recently, we found that the Src family kinase Fyn phosphorylates the catalytic subunit of PKA (PKA-C) at Y69, thereby increasing PKA kinase activity. We also showed that Fyn induced the phosphorylation of cellular proteins within the PKA preferred target motif. This led to the hypothesis that Fyn could affect proteins in complex with PKA. To test this, we employed a quantitative mass spectrometry approach to identify Fyn-dependent binding partners in complex with PKA-C. We found Fyn enhanced the binding of PKA-C to several cytoskeletal regulators that localize to the centrosome and Golgi apparatus. Three of these Fyn-induced PKA interactors, AKAP9, PDE4DIP, and CDK5RAP2, were validated biochemically and were shown to exist in complex with Fyn and PKA in a glioblastoma cell line. Intriguingly, the complexes formed between PKA-C and these known AKAPs were dependent upon Fyn catalytic activity and expression levels. In addition, we identified Fyn-regulated phosphorylation sites on proteins in complex with PKA-C. We also identified and biochemically validated a novel PKA-C interactor, LARP4, which complexed with PKA in the absence of Fyn. These results demonstrate the ability of Fyn to influence the docking of PKA to specific cellular scaffolds and suggest that Fyn may affect the downstream substrates targeted by PKA.

scholarly journals The A-kinase-anchoring protein AKAP-Lbc facilitates cardioprotective PKA phosphorylation of Hsp20 on Ser16

2012 ◽  
Vol 446 (3) ◽  
pp. 437-443 ◽  
Author(s):  
Helen V. Edwards ◽  
John D. Scott ◽  
George S. Baillie
Keyword(s):  
Molecular Processes ◽  
Dependent Protein Kinase ◽  
Ischaemia Reperfusion Injury ◽  
Ischaemia Reperfusion ◽  
Anchoring Proteins ◽  
Anchoring Protein ◽  
Extracellular Stimuli ◽  
Dependent Protein ◽  
A Cell ◽  
Apoptotic Effects

Hsp20 (heat-shock protein of 20 kDa; HspB6) is a cardioprotective agent which combats a number of pathophysiological processes in the heart, including hypertrophy, apoptosis and ischaemia/reperfusion injury. The cardioprotective actions of Hsp20 require its phosphorylation by PKA (cAMP-dependent protein kinase) on Ser16. Although the extracellular stimuli that promote cAMP-responsive phosphorylation of Hsp20 are well known, less is understood about the molecular processes that regulate this modification. AKAPs (A-kinase-anchoring proteins) physically compartmentalize PKA to specific locations within a cell to both direct PKA phosphorylation toward selected substrates and to orchestrate downstream signalling events. In the present study we used PKA anchoring disruptor peptides to verify that an AKAP underpins the cardioprotective phosphorylation of Hsp20. Biochemical and immunofluorescence techniques identify the cytosolic protein AKAP-Lbc (AKAP13) as the anchoring protein responsible for directing PKA phosphorylation of Hsp20 on Ser16. Gene silencing and rescue experiments establish that AKAP-Lbc-mediated PKA phosphorylation of Hsp20 is crucial to the anti-apoptotic effects of the Hsp. Thus AKAP-Lbc may serve an ancillary cardioprotective role by favouring the association of PKA with Hsp20.

Subcellular Localization of the Type II cAMP-Dependent Protein Kinase

Physiology ◽  
1992 ◽  
Vol 7 (4) ◽  
pp. 143-148 ◽  
Author(s):  
JD Scott ◽  
DW Carr
Keyword(s):  
Protein Kinase ◽  
Protein Interactions ◽  
Regulatory Subunit ◽  
Type Ii ◽  
Protein Protein Interactions ◽  
Dependent Protein Kinase ◽  
Biochemical Effects ◽  
Camp Dependent Protein Kinase ◽  
Anchoring Proteins ◽  
Dependent Protein

Diverse biochemical effects of different neurotransmitters or hormones that stimulate cAMP production may occur through activation of compartmentalized pools of cAMP-dependent protein kinase (PKA). Evidence suggests that compartmentalization of type II PKA is maintained through protein-protein interactions between the regulatory subunit and specific anchoring proteins.

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