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Christopher J Penny, Matthew G Gold
Calcineurin and calmodulin-dependent protein kinase II (CaMKII) are both highly abundant in neurons, and both are activated by calmodulin at similar Ca2+ concentrations in the test tube. However, they fulfill opposite functions in dendritic spines, with CaMKII activity driving long-term synaptic potentiation following large influxes of Ca2+ through NMDA-type glutamate receptors (NMDARs), and calcineurin responding to smaller influxes of Ca2+ through the same receptors to induce long-term depression. In this review, we explore the notion that precise dynamic localisation of the two enzymes at different sites within dendritic spines is fundamental to this behavior...
May 27, 2018: Cellular Signalling
Aixa F Rivera-Pagán, Miguel P Méndez-González, David E Rivera-Aponte, Christian J Malpica-Nieves, Katya V Melnik-Martínez, Astrid Zayas-Santiago, Gerónimo Maldonado-Martínez, Yaroslav M Shuba, Serguei N Skatchkov, Misty J Eaton
A-kinase-anchoring proteins, AKAPs, are scaffolding proteins that associate with kinases and phosphatases, and direct them to a specific submembrane site to coordinate signaling events. AKAP150, a rodent ortholog of human AKAP79, has been extensively studied in neurons, but very little is known about the localization and function of AKAP150 in astrocytes, the major cell type in brain. Thus, in this study, we assessed the localization of AKAP150 in astrocytes and elucidated its role during physiological and ischemic conditions...
May 23, 2018: Neuroscience
Anton Omelchenko, Bonnie L Firestein
Long-term depression (LTD) is a reduction in the efficacy of neuronal synapses, but the molecular basis of LTD signaling and how these signals lead to phenotypic outcomes, such as the shrinkage of synaptic regions, is not clear. In a new report, Woolfrey et al use chemically-induced LTD and a multitude of in vitro biochemical assays to provide evidence that synaptic removal of the scaffolding protein AKAP79/150 promotes LTD-induced spine shrinkage. The further identification of CaMKII, a kinase primarily associated with long-term potentiation (LTP), as a requirement for AKAP79/150 removal, uncovers unexpected interplay between different post-translational modifications and points to a new model of LTD...
February 2, 2018: Journal of Biological Chemistry
Kevin M Woolfrey, Heather O'Leary, Dayton J Goodell, Holly R Robertson, Eric A Horne, Steven J Coultrap, Mark L Dell'Acqua, K Ulrich Bayer
Both long-term potentiation (LTP) and depression (LTD) of excitatory synapse strength require the Ca2+ /calmodulin (CaM)-dependent protein kinase II (CaMKII) and its autonomous activity generated by Thr-286 autophosphorylation. Additionally, LTP and LTD are correlated with dendritic spine enlargement and shrinkage that are accompanied by the synaptic accumulation or removal, respectively, of the AMPA-receptor regulatory scaffold protein A-kinase anchoring protein (AKAP) 79/150. We show here that the spine shrinkage associated with LTD indeed requires synaptic AKAP79/150 removal, which in turn requires CaMKII activity...
February 2, 2018: Journal of Biological Chemistry
Neha Patel, Florian Stengel, Ruedi Aebersold, Matthew G Gold
AKAP79/150 is essential for coordinating second messenger-responsive enzymes in processes including synaptic long-term depression. Ca2+ directly regulates AKAP79 through its effector calmodulin (CaM), but the molecular basis of this regulation was previously unknown. Here, we report that CaM recognizes a '1-4-7-8' pattern of hydrophobic amino acids starting at Trp79 in AKAP79. Cross-linking coupled to mass spectrometry assisted mapping of the interaction site. Removal of the CaM-binding sequence in AKAP79 prevents formation of a Ca2+ -sensitive interface between AKAP79 and calcineurin, and increases resting cellular PKA phosphorylation...
November 22, 2017: Nature Communications
Patrick J Nygren, Sohum Mehta, Devin K Schweppe, Lorene K Langeberg, Jennifer L Whiting, Chad R Weisbrod, James E Bruce, Jin Zhang, David Veesler, John D Scott
Scaffolding the calcium/calmodulin-dependent phosphatase 2B (PP2B, calcineurin) focuses and insulates termination of local second messenger responses. Conformational flexibility in regions of intrinsic disorder within A-kinase anchoring protein 79 (AKAP79) delineates PP2B access to phosphoproteins. Structural analysis by negative-stain electron microscopy (EM) reveals an ensemble of dormant AKAP79-PP2B configurations varying in particle length from 160 to 240 Å. A short-linear interaction motif between residues 337-343 of AKAP79 is the sole PP2B-anchoring determinant sustaining these diverse topologies...
October 2, 2017: ELife
Christine Salaun, Louise Ritchie, Jennifer Greaves, Trevor J Bushell, Luke H Chamberlain
The S-acyltransferase zDHHC2 mediates dynamic S-acylation of PSD95 and AKAP79/150, which impacts synaptic targeting of AMPA receptors. zDHHC2 is responsive to synaptic activity and catalyses the increased S-acylation of PSD95 that occurs following action potential blockade or application of ionotropic glutamate receptor antagonists. These treatments have been proposed to increase plasma membrane delivery of zDHHC2 via an endosomal cycling pathway, enhancing substrate accessibility. To generate an improved understanding of zDHHC2 trafficking and how this might be regulated by neuronal activity, we searched for intramolecular signals that regulate enzyme localisation...
December 2017: Molecular and Cellular Neurosciences
F Donelson Smith, Jessica L Esseltine, Patrick J Nygren, David Veesler, Dominic P Byrne, Matthias Vonderach, Ilya Strashnov, Claire E Eyers, Patrick A Eyers, Lorene K Langeberg, John D Scott
Hormones can transmit signals through adenosine 3',5'-monophosphate (cAMP) to precise intracellular locations. The fidelity of these responses relies on the activation of localized protein kinase A (PKA) holoenzymes. Association of PKA regulatory type II (RII) subunits with A-kinase-anchoring proteins (AKAPs) confers location, and catalytic (C) subunits phosphorylate substrates. Single-particle electron microscopy demonstrated that AKAP79 constrains RII-C subassemblies within 150 to 250 angstroms of its targets...
June 23, 2017: Science
Konrad Mack, Michael J M Fischer
TRPV4 ion channels have a broad expression profile and were shown to contribute to enhanced pain sensation in inflammation. Directly blocking TRPV4 might run the risk of interfering with normal physiology, and has prompted to explore the interaction with the scaffolding protein AKAP79, an approach successfully used for TRPV1 channels. HEK293t cells express AKAP79, additional transfection did not sensitize human TRPV4. Application of trypsin facilitated responses to TRPV4 agonist GSK1016790A. Using a specific protease-activated receptor 2 agonist, involvement of an A-kinase anchoring protein in TRPV4 activation was demonstrated by inhibition with AKAP inhibitor peptide Ht31...
June 3, 2017: Neuroscience
Claudia Seyler, Daniel Scherer, Christoph Köpple, Martin Kulzer, Sevil Korkmaz, Panagiotis Xynogalos, Dierk Thomas, Ziya Kaya, Eberhard Scholz, Johannes Backs, Christoph Karle, Hugo A Katus, Edgar Zitron
The cardiac IK1 current stabilizes the resting membrane potential of cardiomyocytes. Protein kinase A (PKA) induces an inhibition of IK1 current which strongly promotes focal arrhythmogenesis. The molecular mechanisms underlying this regulation have only partially been elucidated yet. Furthermore, the role of A-kinase anchoring proteins (AKAPs) in this regulation has not been examined to date. The objective of this project was to elucidate the molecular mechanisms underlying the inhibition of IK1 by PKA and to identify novel molecular targets for antiarrhythmic therapy downstream β-adrenoreceptors...
May 2017: Naunyn-Schmiedeberg's Archives of Pharmacology
Pablo Muñoz-Llancao, Cristian de Gregorio, Macarena Las Heras, Christopher Meinohl, Kevin Noorman, Erik Boddeke, Xiaodong Cheng, Frank Lezoualc'h, Martina Schmidt, Christian Gonzalez-Billault
Neurons are highly differentiated cells responsible for the conduction and transmission of information in the nervous system. The proper function of a neuron relies on the compartmentalization of their intracellular domains. Differentiated neuroblastoma cells have been extensively used to study and understand the physiology and cell biology of neuronal cells. Here, we show that differentiation of N1E-115 neuroblastoma cells is more pronounced upon exposure of a chemical analog of cyclic AMP (cAMP), db-cAMP...
March 2017: Cytoskeleton
Raquel Guinzberg, Antonio Díaz-Cruz, Carlos Acosta-Trujillo, María Magdalena Vilchis-Landeros, Héctor Vázquez-Meza, Carlos Lozano-Flores, Natalia Chiquete-Felix, Alfredo Varela-Echavarría, Salvador Uribe-Carvajal, Héctor Riveros-Rosas, Enrique Piña
Spatiotemporal regulation of cAMP within the cell is required to achieve receptor-specific responses. The mechanism through which the cell selects a specific response to newly synthesized cAMP is not fully understood. In hepatocyte plasma membranes, we identified two functional and independent cAMP-responsive signaling protein macrocomplexes that produce, use, degrade, and regulate their own nondiffusible (sequestered) cAMP pool to achieve their specific responses. Each complex responds to the stimulation of an adenosine G protein-coupled receptor (Ado-GPCR), bound to either A2A or A2B , but not simultaneously to both...
January 2017: FEBS Journal
Jie Zhang, Chase M Carver, Frank S Choveau, Mark S Shapiro
The fidelity of neuronal signaling requires organization of signaling molecules into macromolecular complexes, whose components are in intimate proximity. The intrinsic diffraction limit of light makes visualization of individual signaling complexes using visible light extremely difficult. However, using super-resolution stochastic optical reconstruction microscopy (STORM), we observed intimate association of individual molecules within signaling complexes containing ion channels (M-type K(+), L-type Ca(2+), or TRPV1 channels) and G protein-coupled receptors coupled by the scaffolding protein A-kinase-anchoring protein (AKAP)79/150...
October 19, 2016: Neuron
Chong Han, Hirofumi Tomita, Takayoshi Ohba, Kimitaka Nishizaki, Yoshiki Ogata, Yasushi Matsuzaki, Daisuke Sawamura, Teruyuki Yanagisawa, Tomohiro Osanai, Tadaatsu Imaizumi, Atsushi Matsubara, Takeshi Adachi, Kyoichi Ono, Ken Okumura, Manabu Murakami
Genetic analyses have revealed an important association between A-kinase anchoring proteins (AKAPs) and the intracellular calcium modulating system. AKAP5, also known as AKAP79/150, is an anchoring protein between PKA and voltage-dependent calcium channels, ryanodine receptor-2, phospholamban and other molecules. The aim of the present study was to elucidate the physiological importance of AKAP5 in the creation of cardiac rhythm using AKAP5-null mice. ECG analysis showed a normal sinus rhythm and a decreased responsiveness to isoproterenol in AKAP5-null mice compared with wild-type mice...
January 22, 2016: Biochemical and Biophysical Research Communications
Hee Yeon Kay, Derek L Greene, Seungwoo Kang, Anastasia Kosenko, Naoto Hoshi
Valproic acid (VPA) has been widely used for decades to treat epilepsy; however, its mechanism of action remains poorly understood. Here, we report that the anticonvulsant effects of nonacute VPA treatment involve preservation of the M-current, a low-threshold noninactivating potassium current, during seizures. In a wide variety of neurons, activation of Gq-coupled receptors, such as the m1 muscarinic acetylcholine receptor, suppresses the M-current and induces hyperexcitability. We demonstrated that VPA treatment disrupts muscarinic suppression of the M-current and prevents resultant agonist-induced neuronal hyperexcitability...
October 1, 2015: Journal of Clinical Investigation
Amy S Bogard, Steven J Tavalin
PKMζ is generated via an alternative transcriptional start site in the atypical protein kinase C (PKC)ζ isoform, which removes N-terminal regulatory elements, including the inhibitory pseudosubstrate domain, consequently rendering the kinase constitutively active. Persistent PKMζ activity has been proposed as a molecular mechanism for the long-term maintenance of synaptic plasticity underlying some forms of memory. Many studies supporting a role for PKMζ in synaptic plasticity and memory have relied on the PKCζ pseudosubstrate-derived ζ-inhibitory peptide (ZIP)...
October 2015: Molecular Pharmacology
Kui Chen, Yu An, Lu Tie, Yan Pan, Xuejun Li
Now stimulation of AMPA receptor as well as its downstream pathways is considered as potential central mediators in antidepressant mechanisms. As a signal integrator which binds to AMPA receptor, A-kinase anchoring protein 79-(AKAP79-) PKA complex is regarded as a potential drug target to exert neuroprotective effects. A well-tolerated and multitarget drug curcumin has been confirmed to exert antidepressant-like effects. To explore whether AKAP79-PKA complex is involved in curcumin-mediated antiexcitotoxicity, we detected calcium signaling, subcellular location of AKAP79-PKA complex, phosphorylation of glutamate receptor, and ERK and AKT cascades...
2015: Evidence-based Complementary and Alternative Medicine: ECAM
Michael E Authement, Jayaraj N Kodangattil, Shawn Gouty, Milan Rusnak, Aviva J Symes, Brian M Cox, Fereshteh S Nugent
Adverse early-life experiences such as child neglect and abuse increase the risk of developing addiction and stress-related disorders through alterations in motivational systems including the mesolimbic dopamine (DA) pathway. Here we investigated whether a severe early-life stress (i.e., maternal deprivation, MD) promotes DA dysregulation through an epigenetic impairment of synaptic plasticity within ventral tegmental area (VTA) DA neurons. Using a single 24-hr episode of MD and whole-cell patch clamp recording in rat midbrain slices, we show that MD selectively induces long-term depression (LTD) and shifts spike timing-dependent plasticity (STDP) toward LTD at GABAergic synapses onto VTA DA neurons through epigenetic modifications of postsynaptic scaffolding A-kinase anchoring protein 79/150 (AKAP79/150) signaling...
June 3, 2015: Neuron
Ilse Delint-Ramirez, Debbie Willoughby, Gerald R V Hammond, Laura J Ayling, Dermot M F Cooper
No abstract text is available yet for this article.
May 22, 2015: Journal of Biological Chemistry
Bret K Samelson, Bryan B Gore, Jennifer L Whiting, Patrick J Nygren, Alicia M Purkey, Marcie Colledge, Lorene K Langeberg, Mark L Dell'Acqua, Larry S Zweifel, John D Scott
Anchoring proteins direct protein kinases and phosphoprotein phosphatases toward selected substrates to control the efficacy, context, and duration of neuronal phosphorylation events. The A-kinase anchoring protein AKAP79/150 interacts with protein kinase A (PKA), protein kinase C (PKC), and protein phosphatase 2B (calcineurin) to modulate second messenger signaling events. In a mass spectrometry-based screen for additional AKAP79/150 binding partners, we have identified the Roundabout axonal guidance receptor Robo2 and its ligands Slit2 and Slit3...
May 29, 2015: Journal of Biological Chemistry
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