1
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Shirani M, Levin S, Shebl B, Requena D, Finkelstein TM, Johnson DS, Ng D, Lalazar G, Heissel S, Hojrup P, Molina H, de Jong YP, Rice CM, Singhi AD, Torbenson MS, Coffino P, Lyons B, Simon SM. Increased Protein Kinase A Activity Induces Fibrolamellar Hepatocellular Carcinoma Features Independent of DNAJB1. Cancer Res 2024; 84:2626-2644. [PMID: 38888469 PMCID: PMC11325150 DOI: 10.1158/0008-5472.can-23-4110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/15/2024] [Accepted: 06/04/2024] [Indexed: 06/20/2024]
Abstract
Fibrolamellar hepatocellular carcinoma (FLC) is a rare liver cancer that is driven by the fusion of DNAJB1 and PRKACA, the catalytic subunit of protein kinase A (PKA). PKA activity is controlled through regulatory proteins that both inhibit catalytic activity and control localization, and an excess of regulatory subunits ensures PRKACA activity is inhibited. Here, we found an increase in the ratio of catalytic to regulatory units in FLC patient tumors driven by DNAJB1::PRKACA using mass spectrometry, biochemistry, and immunofluorescence, with increased nuclear localization of the kinase. Overexpression of DNAJB1::PRKACA, ATP1B1::PRKACA, or PRKACA, but not catalytically inactive kinase, caused similar transcriptomic changes in primary human hepatocytes, recapitulating the changes observed in FLC. Consistently, tumors in patients missing a regulatory subunit or harboring an ATP1B1::PRKACA fusion were indistinguishable from FLC based on the histopathological, transcriptomic, and drug-response profiles. Together, these findings indicate that the DNAJB1 domain of DNAJB1::PRKACA is not required for FLC. Instead, changes in PKA activity and localization determine the FLC phenotype. Significance: Alterations leading to unconstrained protein kinase A signaling, regardless of the presence or absence of PRKACA fusions, drive the phenotypes of fibrolamellar hepatocellular carcinoma, reshaping understanding of the pathogenesis of this rare liver cancer.
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Affiliation(s)
- Mahsa Shirani
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - Solomon Levin
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - Bassem Shebl
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - David Requena
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - Tova M. Finkelstein
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - Daniel S. Johnson
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
- Department of Physics and Astronomy, Hofstra University, Hempstead, New York.
| | - Denise Ng
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - Gadi Lalazar
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - Søren Heissel
- Proteomics Resource Center, The Rockefeller University, New York, New York.
| | - Peter Hojrup
- Department of Biochemistry and Molecular Biology. University of Southern Denmark, Odense, Denmark.
| | - Henrik Molina
- Proteomics Resource Center, The Rockefeller University, New York, New York.
| | - Ype P. de Jong
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, New York.
- Division of Gastroenterology and Hepatology, Weill Cornell Medicine, New York, New York.
| | - Charles M. Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, New York.
| | - Aatur D. Singhi
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
| | | | - Philip Coffino
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
| | - Barbara Lyons
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico.
| | - Sanford M. Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York.
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2
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Lee CT, Bell M, Bonilla-Quintana M, Rangamani P. Biophysical Modeling of Synaptic Plasticity. Annu Rev Biophys 2024; 53:397-426. [PMID: 38382115 DOI: 10.1146/annurev-biophys-072123-124954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Dendritic spines are small, bulbous compartments that function as postsynaptic sites and undergo intense biochemical and biophysical activity. The role of the myriad signaling pathways that are implicated in synaptic plasticity is well studied. A recent abundance of quantitative experimental data has made the events associated with synaptic plasticity amenable to quantitative biophysical modeling. Spines are also fascinating biophysical computational units because spine geometry, signal transduction, and mechanics work in a complex feedback loop to tune synaptic plasticity. In this sense, ideas from modeling cell motility can inspire us to develop multiscale approaches for predictive modeling of synaptic plasticity. In this article, we review the key steps in postsynaptic plasticity with a specific focus on the impact of spine geometry on signaling, cytoskeleton rearrangement, and membrane mechanics. We summarize the main experimental observations and highlight how theory and computation can aid our understanding of these complex processes.
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Affiliation(s)
- Christopher T Lee
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
| | - Miriam Bell
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
| | - Mayte Bonilla-Quintana
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
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Olivieri C, Wang Y, Walker C, Subrahmanian MV, Ha KN, Bernlohr D, Gao J, Camilloni C, Vendruscolo M, Taylor SS, Veglia G. The αC-β4 loop controls the allosteric cooperativity between nucleotide and substrate in the catalytic subunit of protein kinase A. eLife 2024; 12:RP91506. [PMID: 38913408 PMCID: PMC11196109 DOI: 10.7554/elife.91506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024] Open
Abstract
Allosteric cooperativity between ATP and substrates is a prominent characteristic of the cAMP-dependent catalytic subunit of protein kinase A (PKA-C). This long-range synergistic action is involved in substrate recognition and fidelity, and it may also regulate PKA's association with regulatory subunits and other binding partners. To date, a complete understanding of this intramolecular mechanism is still lacking. Here, we integrated NMR(Nuclear Magnetic Resonance)-restrained molecular dynamics simulations and a Markov State Model to characterize the free energy landscape and conformational transitions of PKA-C. We found that the apoenzyme populates a broad free energy basin featuring a conformational ensemble of the active state of PKA-C (ground state) and other basins with lower populations (excited states). The first excited state corresponds to a previously characterized inactive state of PKA-C with the αC helix swinging outward. The second excited state displays a disrupted hydrophobic packing around the regulatory (R) spine, with a flipped configuration of the F100 and F102 residues at the αC-β4 loop. We validated the second excited state by analyzing the F100A mutant of PKA-C, assessing its structural response to ATP and substrate binding. While PKA-CF100A preserves its catalytic efficiency with Kemptide, this mutation rearranges the αC-β4 loop conformation, interrupting the coupling of the two lobes and abolishing the allosteric binding cooperativity. The highly conserved αC-β4 loop emerges as a pivotal element to control the synergistic binding of nucleotide and substrate, explaining how mutations or insertions near or within this motif affect the function and drug sensitivity in homologous kinases.
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Affiliation(s)
- Cristina Olivieri
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
| | - Yingjie Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
- Department of Chemistry and Supercomputing Institute, University of MinnesotaMinneapolisUnited States
| | - Caitlin Walker
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
| | | | - Kim N Ha
- Department of Chemistry and Biochemistry, St. Catherine UniversityMinneapolisUnited States
| | - David Bernlohr
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
| | - Jiali Gao
- Department of Chemistry and Supercomputing Institute, University of MinnesotaMinneapolisUnited States
| | - Carlo Camilloni
- Department of Chemistry, University of CambridgeCambridgeUnited Kingdom
| | | | - Susan S Taylor
- Department of Pharmacology, University of California at San DiegoSan DiegoUnited States
- Department of Chemistry and Biochemistry, University of California at San DiegoSan DiegoUnited States
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
- Department of Chemistry and Supercomputing Institute, University of MinnesotaMinneapolisUnited States
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4
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Kang M, Otani Y, Guo Y, Yan J, Goult BT, Howe AK. The focal adhesion protein talin is a mechanically gated A-kinase anchoring protein. Proc Natl Acad Sci U S A 2024; 121:e2314947121. [PMID: 38513099 PMCID: PMC10990152 DOI: 10.1073/pnas.2314947121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 02/22/2024] [Indexed: 03/23/2024] Open
Abstract
Protein kinase A (PKA) is a ubiquitous, promiscuous kinase whose activity is specified through subcellular localization mediated by A-kinase anchoring proteins (AKAPs). PKA has complex roles as both an effector and a regulator of integrin-mediated cell adhesion to extracellular matrix (ECM). Recent observations demonstrate that PKA is an active component of focal adhesions (FA), suggesting the existence of one or more FA AKAPs. Using a promiscuous biotin ligase fused to PKA type-IIα regulatory (RIIα) subunits and subcellular fractionation, we identify the archetypal FA protein talin1 as an AKAP. Talin is a large, mechanosensitive scaffold that directly links integrins to actin filaments and promotes FA assembly by recruiting additional components in a force-dependent manner. The rod region of talin1 consists of 62 α-helices bundled into 13 rod domains, R1 to R13. Direct binding assays and NMR spectroscopy identify helix41 in the R9 subdomain of talin as the PKA binding site. PKA binding to helix41 requires unfolding of the R9 domain, which requires the linker region between R9 and R10. Experiments with single molecules and in cells manipulated to alter actomyosin contractility demonstrate that the PKA-talin interaction is regulated by mechanical force across the talin molecule. Finally, talin mutations that disrupt PKA binding also decrease levels of total and phosphorylated PKA RII subunits as well as phosphorylation of VASP, a known PKA substrate, within FA. These observations identify a mechanically gated anchoring protein for PKA, a force-dependent binding partner for talin1, and a potential pathway for adhesion-associated mechanotransduction.
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Affiliation(s)
- Mingu Kang
- Department of Pharmacology, University of Vermont Larner College of Medicine, Burlington, VT05405
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT05405
- University of Vermont Cancer Center, Burlington, VT05405
| | - Yasumi Otani
- School of Biosciences, University of Kent, Canterbury, KentCT2 7NJ, United Kingdom
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, LiverpoolL69 7ZB, United Kingdom
| | - Yanyu Guo
- Department of Physics, Mechanobiology Institute, National University of Singapore, Singapore117542, Singapore
| | - Jie Yan
- Department of Physics, Mechanobiology Institute, National University of Singapore, Singapore117542, Singapore
| | - Benjamin T. Goult
- School of Biosciences, University of Kent, Canterbury, KentCT2 7NJ, United Kingdom
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, LiverpoolL69 7ZB, United Kingdom
| | - Alan K. Howe
- Department of Pharmacology, University of Vermont Larner College of Medicine, Burlington, VT05405
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT05405
- University of Vermont Cancer Center, Burlington, VT05405
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5
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Alsaidan OA, Onobun E, Ye C, Lou L, Beharry Z, Xie ZR, Lebedyeva I, Crich D, Cai H. Inhibition of N-myristoyltransferase activity promotes androgen receptor degradation in prostate cancer. Prostate 2024; 84:254-268. [PMID: 37905842 PMCID: PMC10872856 DOI: 10.1002/pros.24645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 11/02/2023]
Abstract
BACKGROUND Even though prostate cancer (PCa) patients initially respond to androgen deprivation therapy, some will eventually develop castration resistant prostate cancer (CRPC). Androgen receptor (AR) mediated cell signaling is a major driver in the progression of CRPC while only a fraction of PCa becomes AR negative. This study aimed to understand the regulation of AR levels by N-myristoyltransferase in PCa cells. METHODS Two enantiomers, (1S,2S)- d-NMAPPD and (1R,2R)- d-NMAPPD (LCL4), were characterized by various methods (1 H and 13 C NMR, UHPLC, high-resolution mass spectra, circular dichroism) and evaluated for the ability to bind to N-myristoyltransferase 1 (NMT1) using computational docking analysis. structure-activity relationship analysis of these compounds led to the synthesis of (1R,2R)-LCL204 and evaluation as a potential NMT1 inhibitor utilizing the purified full length NMT1 enzyme. The NMT inhibitory activity wase determined by Click chemistry and immunoblotting. Regulation of NMT1 on tumor growth was evaluated in a xenograft tumor model. RESULTS (1R,2R)- d-NMAPPD, but not its enantiomer (1S,2S)- d-NMAPPD, inhibited NMT1 activity and reduced AR protein levels. (1R,2R)-LCL204, a derivative of (1R,2R)- d-NMAPPD, inhibited global protein myristoylation. It also suppressed protein levels, nuclear translocation, and transcriptional activity of AR full-length or variants in PCa cells. This was due to enhanced ubiquitin and proteasome-mediated degradation of AR. Knockdown of NMT1 levels inhibited tumor growth and proliferation of cancer cells. CONCLUSION Inhibitory efficacy on N-myristoyltransferase activity by d-NMAPPD is stereospecific. (1R,2R)-LCL204 reduced global N-myristoylation and androgen receptor protein levels at low micromolar concentrations in prostate cancer cells. pharmacological inhibition of NMT1 enhances ubiquitin-mediated proteasome degradation of AR. This study illustrates a novel function of N-myristoyltransferase and provides a potential strategy for treatment of CRPC.
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Affiliation(s)
- Omar Awad Alsaidan
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia Athens, Athens, Georgia 30602
| | - Emmanuel Onobun
- Department of Chemistry, Franklin College of Arts and Sciences, University of Georgia Athens, Athens, Georgia 30602
| | - Chenming Ye
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia Athens, Athens, Georgia 30602
| | - Lei Lou
- School of Electrical and Computer Engineering, College of Engineering, University of Georgia Athens, Athens, Georgia 30602
| | - Zanna Beharry
- Department of Chemical and Physical Sciences, University of the Virgin Islands, St. Thomas, VI 00802
| | - Zhong-Ru Xie
- School of Electrical and Computer Engineering, College of Engineering, University of Georgia Athens, Athens, Georgia 30602
| | - Iryna Lebedyeva
- Department of Chemistry and Physics, Augusta University, Augusta, Georgia 30912
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia Athens, Athens, Georgia 30602
- Department of Chemistry, Franklin College of Arts and Sciences, University of Georgia Athens, Athens, Georgia 30602
| | - Houjian Cai
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia Athens, Athens, Georgia 30602
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6
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Xiong WH, Qin M, Zhong H. PKA regulation of neuronal function requires the dissociation of catalytic subunits from regulatory subunits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.05.556437. [PMID: 37732264 PMCID: PMC10508765 DOI: 10.1101/2023.09.05.556437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Protein kinase A (PKA) plays essential roles in diverse cellular functions. However, the spatiotemporal dynamics of endogenous PKA upon activation remain debated. The classical model predicts that PKA catalytic subunits dissociate from regulatory subunits in the presence of cAMP, whereas a second model proposes that catalytic subunits remain associated with regulatory subunits following physiological activation. Here we report that different PKA subtypes, as defined by the regulatory subunit, exhibit distinct subcellular localization at rest in CA1 neurons of cultured hippocampal slices. Nevertheless, when all tested PKA subtypes are activated by norepinephrine, presumably via the β-adrenergic receptor, catalytic subunits translocate to dendritic spines but regulatory subunits remain unmoved. These differential spatial dynamics between the subunits indicate that at least a significant fraction of PKA dissociates. Furthermore, PKA-dependent regulation of synaptic plasticity and transmission can be supported only by wildtype, dissociable PKA, but not by inseparable PKA. These results indicate that endogenous PKA regulatory and catalytic subunits dissociate to achieve PKA function in neurons.
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Affiliation(s)
- Wei-Hong Xiong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Maozhen Qin
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Haining Zhong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
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7
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Vu CQ, Arai S. Quantitative Imaging of Genetically Encoded Fluorescence Lifetime Biosensors. BIOSENSORS 2023; 13:939. [PMID: 37887132 PMCID: PMC10605767 DOI: 10.3390/bios13100939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 10/28/2023]
Abstract
Genetically encoded fluorescence lifetime biosensors have emerged as powerful tools for quantitative imaging, enabling precise measurement of cellular metabolites, molecular interactions, and dynamic cellular processes. This review provides an overview of the principles, applications, and advancements in quantitative imaging with genetically encoded fluorescence lifetime biosensors using fluorescence lifetime imaging microscopy (go-FLIM). We highlighted the distinct advantages of fluorescence lifetime-based measurements, including independence from expression levels, excitation power, and focus drift, resulting in robust and reliable measurements compared to intensity-based approaches. Specifically, we focus on two types of go-FLIM, namely Förster resonance energy transfer (FRET)-FLIM and single-fluorescent protein (FP)-based FLIM biosensors, and discuss their unique characteristics and benefits. This review serves as a valuable resource for researchers interested in leveraging fluorescence lifetime imaging to study molecular interactions and cellular metabolism with high precision and accuracy.
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Affiliation(s)
- Cong Quang Vu
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Satoshi Arai
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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8
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Kang M, Otani Y, Guo Y, Yan J, Goult BT, Howe AK. The focal adhesion protein talin is a mechanically-gated A-kinase anchoring protein (AKAP). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.20.554038. [PMID: 37645895 PMCID: PMC10462126 DOI: 10.1101/2023.08.20.554038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The cAMP-dependent protein kinase (Protein Kinase A; PKA) is a ubiquitous, promiscuous kinase whose activity is focused and specified through subcellular localization mediated by A-kinase anchoring proteins (AKAPs). PKA has complex roles as both an effector and a regulator of integrin-mediated cell adhesion to the extracellular matrix (ECM). Recent observations demonstrate that PKA is an active component of focal adhesions (FA), intracellular complexes coupling ECM-bound integrins to the actin cytoskeleton, suggesting the existence of one or more FA AKAPs. Using a combination of a promiscuous biotin ligase fused to PKA type-IIα regulatory (RIIα) subunits and subcellular fractionation, we identify the archetypal FA protein talin1 as an AKAP. Talin is a large, mechanosensitive scaffold that directly links integrins to actin filaments and promotes FA assembly by recruiting additional components in a force-dependent manner. The rod region of talin1 consists of 62 α-helices bundled into 13 rod domains, R1-R13. Direct binding assays and nuclear magnetic resonance spectroscopy identify helix41 in the R9 subdomain of talin as the PKA binding site. PKA binding to helix41 requires unfolding of the R9 domain, which requires the linker region between R9 and R10. Finally, single-molecule experiments with talin1 and PKA, and experiments in cells manipulated to alter actomyosin contractility demonstrate that the PKA-talin interaction is regulated by mechanical force across the talin molecule. These observations identify the first mechanically-gated anchoring protein for PKA, a new force-dependent binding partner for talin1, and thus a new mechanism for coupling cellular tension and signal transduction.
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9
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Cakir Z, Lord SJ, Zhou Y, Jang GM, Polacco BJ, Eckhardt M, Jimenez-Morales D, Newton BW, Orr AL, Johnson JR, da Cruz A, Mullins RD, Krogan NJ, Mahley RW, Swaney DL. Quantitative Proteomic Analysis Reveals apoE4-Dependent Phosphorylation of the Actin-Regulating Protein VASP. Mol Cell Proteomics 2023; 22:100541. [PMID: 37019383 PMCID: PMC10196575 DOI: 10.1016/j.mcpro.2023.100541] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 02/03/2023] [Accepted: 03/24/2023] [Indexed: 04/05/2023] Open
Abstract
Apolipoprotein (apo) E4 is the major genetic risk factor for Alzheimer's disease. While neurons generally produce a minority of the apoE in the central nervous system, neuronal expression of apoE increases dramatically in response to stress and is sufficient to drive pathology. Currently, the molecular mechanisms of how apoE4 expression may regulate pathology are not fully understood. Here, we expand upon our previous studies measuring the impact of apoE4 on protein abundance to include the analysis of protein phosphorylation and ubiquitylation signaling in isogenic Neuro-2a cells expressing apoE3 or apoE4. ApoE4 expression resulted in a dramatic increase in vasodilator-stimulated phosphoprotein (VASP) S235 phosphorylation in a protein kinase A (PKA)-dependent manner. This phosphorylation disrupted VASP interactions with numerous actin cytoskeletal and microtubular proteins. Reduction of VASP S235 phosphorylation via PKA inhibition resulted in a significant increase in filopodia formation and neurite outgrowth in apoE4-expressing cells, exceeding levels observed in apoE3-expressing cells. Our results highlight the pronounced and diverse impact of apoE4 on multiple modes of protein regulation and identify protein targets to restore apoE4-related cytoskeletal defects.
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Affiliation(s)
- Zeynep Cakir
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - Samuel J Lord
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Howard Hughes Medical Institute, San Francisco, California, USA
| | - Yuan Zhou
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - Gwendolyn M Jang
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - Benjamin J Polacco
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - Manon Eckhardt
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - David Jimenez-Morales
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - Billy W Newton
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - Adam L Orr
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, California, USA
| | - Jeffrey R Johnson
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | | | - R Dyche Mullins
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Howard Hughes Medical Institute, San Francisco, California, USA
| | - Nevan J Krogan
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA
| | - Robert W Mahley
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, California, USA; Departments of Pathology and Medicine, University of California San Francisco, San Francisco, California, USA
| | - Danielle L Swaney
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, California, USA.
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10
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Kovanich D, Low TY, Zaccolo M. Using the Proteomics Toolbox to Resolve Topology and Dynamics of Compartmentalized cAMP Signaling. Int J Mol Sci 2023; 24:4667. [PMID: 36902098 PMCID: PMC10003371 DOI: 10.3390/ijms24054667] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/04/2023] Open
Abstract
cAMP is a second messenger that regulates a myriad of cellular functions in response to multiple extracellular stimuli. New developments in the field have provided exciting insights into how cAMP utilizes compartmentalization to ensure specificity when the message conveyed to the cell by an extracellular stimulus is translated into the appropriate functional outcome. cAMP compartmentalization relies on the formation of local signaling domains where the subset of cAMP signaling effectors, regulators and targets involved in a specific cellular response cluster together. These domains are dynamic in nature and underpin the exacting spatiotemporal regulation of cAMP signaling. In this review, we focus on how the proteomics toolbox can be utilized to identify the molecular components of these domains and to define the dynamic cellular cAMP signaling landscape. From a therapeutic perspective, compiling data on compartmentalized cAMP signaling in physiological and pathological conditions will help define the signaling events underlying disease and may reveal domain-specific targets for the development of precision medicine interventions.
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Affiliation(s)
- Duangnapa Kovanich
- Center for Vaccine Development, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Teck Yew Low
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics and Oxford NIHR Biomedical Research Centre, University of Oxford, Oxford OX1 3PT, UK
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11
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Sensitive genetically encoded sensors for population and subcellular imaging of cAMP in vivo. Nat Methods 2022; 19:1461-1471. [PMID: 36303019 PMCID: PMC10171401 DOI: 10.1038/s41592-022-01646-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 09/09/2022] [Indexed: 01/07/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) signaling integrates information from diverse G-protein-coupled receptors, such as neuromodulator receptors, to regulate pivotal biological processes in a cellular-specific and subcellular-specific manner. However, in vivo cellular-resolution imaging of cAMP dynamics remains challenging. Here, we screen existing genetically encoded cAMP sensors and further develop the best performer to derive three improved variants, called cAMPFIREs. Compared with their parental sensor, these sensors exhibit up to 10-fold increased sensitivity to cAMP and a cytosolic distribution. cAMPFIREs are compatible with both ratiometric and fluorescence lifetime imaging and can detect cAMP dynamics elicited by norepinephrine at physiologically relevant, nanomolar concentrations. Imaging of cAMPFIREs in awake mice reveals tonic levels of cAMP in cortical neurons that are associated with wakefulness, modulated by opioids, and differentially regulated across subcellular compartments. Furthermore, enforced locomotion elicits neuron-specific, bidirectional cAMP dynamics. cAMPFIREs also function in Drosophila. Overall, cAMPFIREs may have broad applicability for studying intracellular signaling in vivo.
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12
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PKR Protects the Major Catalytic Subunit of PKA Cpk1 from FgBlm10-Mediated Proteasome Degradation in Fusarium graminearum. Int J Mol Sci 2022; 23:ijms231810208. [PMID: 36142119 PMCID: PMC9499325 DOI: 10.3390/ijms231810208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
For optimal proteolytic function, the proteasome core (CP or 20S) must associate with activators. The cAMP-PKA pathway is reported to affect the activity of the proteasome in humans. However, the relationship between the proteasome and PKA is not well characterized. Our results showed that the major catalytic subunit Cpk1 was degraded without the protection of Pkr. Eleven (out of 67) pkr suppressors had FgBlm10 C-terminal truncation, one suppressor had an amino acid change mutation in the PRE6 ortholog (FGRRES_07282), and one in the PRE5 ortholog (FGRRES_05222). These mutations rescued the defects in growth and conidial morphology, Cpk1 stability, and PKA activities in the pkr mutant. The interaction of FgBlm10 with FgPre5 and FgPre6 were detected by co-immunoprecipitation, and the essential elements for their interaction were characterized, including the FgBlm10 C-terminus, amino acid D82 of FgPre6 and K62 of FgPre5. Additional FgBlm10-interacting proteins were identified in the wild type and pkr mutant, suggesting that PKA regulates the preference of FgBlm10-mediated proteasome assembly. In addition, PKA indirectly affected the phosphorylation of FgBlm10, and its localization in the nucleus. The truncation of the FgBlm10 C terminus also enhanced nuclear import and bleomycin resistance, suggesting its role in proteasome assembly at DNA damage sites. Collectively, our data demonstrated that regulation between PKA and proteasome degradation is critical for the vegetative growth of F. graminearum.
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13
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Puri NM, Romano GR, Lin TY, Mai QN, Irannejad R. The organic cation Transporter 2 regulates dopamine D1 receptor signaling at the Golgi apparatus. eLife 2022; 11:75468. [PMID: 35467530 PMCID: PMC9098220 DOI: 10.7554/elife.75468] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 04/22/2022] [Indexed: 11/13/2022] Open
Abstract
Dopamine is a key catecholamine in the brain and kidney, where it is involved in a number of physiological functions such as locomotion, cognition, emotion, endocrine regulation, and renal function. As a membrane-impermeant hormone and neurotransmitter, dopamine is thought to signal by binding and activating dopamine receptors, members of the G protein coupled receptor (GPCR) family, only on the plasma membrane. Here, using novel nanobody-based biosensors, we demonstrate for the first time that the dopamine D1 receptor (D1DR), the primary mediator of dopaminergic signaling in the brain and kidney, not only functions on the plasma membrane but becomes activated at the Golgi apparatus in the presence of its ligand. We present evidence that activation of the Golgi pool of D1DR is dependent on organic cation transporter 2 (OCT2), a dopamine transporter, providing an explanation for how the membrane-impermeant dopamine accesses subcellular pools of D1DR. We further demonstrate that dopamine activates Golgi-D1DR in murine striatal medium spiny neurons, and this activity depends on OCT2 function. We also introduce a new approach to selectively interrogate compartmentalized D1DR signaling by inhibiting Gαs coupling using a nanobody-based chemical recruitment system. Using this strategy, we show that Golgi-localized D1DRs regulate cAMP production and mediate local protein kinase A activation. Together, our data suggest that spatially compartmentalized signaling hubs are previously unappreciated regulatory aspects of D1DR signaling. Our data provide further evidence for the role of transporters in regulating subcellular GPCR activity.
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Affiliation(s)
- Natasha M Puri
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Giovanna R Romano
- Biochemistry Department, Weill Cornell Medicine, New York, United States
| | - Ting-Yu Lin
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
| | - Quynh N Mai
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
| | - Roshanak Irannejad
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
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14
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Kocik RA, Gasch AP. Breadth and Specificity in Pleiotropic Protein Kinase A Activity and Environmental Responses. Front Cell Dev Biol 2022; 10:803392. [PMID: 35252178 PMCID: PMC8888911 DOI: 10.3389/fcell.2022.803392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
Protein Kinase A (PKA) is an essential kinase that is conserved across eukaryotes and plays fundamental roles in a wide range of organismal processes, including growth control, learning and memory, cardiovascular health, and development. PKA mediates these responses through the direct phosphorylation of hundreds of proteins-however, which proteins are phosphorylated can vary widely across cell types and environmental cues, even within the same organism. A major question is how cells enact specificity and precision in PKA activity to mount the proper response, especially during environmental changes in which only a subset of PKA-controlled processes must respond. Research over the years has uncovered multiple strategies that cells use to modulate PKA activity and specificity. This review highlights recent advances in our understanding of PKA signaling control including subcellular targeting, phase separation, feedback control, and standing waves of allosteric regulation. We discuss how the complex inputs and outputs to the PKA network simultaneously pose challenges and solutions in signaling integration and insulation. PKA serves as a model for how the same regulatory factors can serve broad pleiotropic functions but maintain specificity in localized control.
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Affiliation(s)
- Rachel A Kocik
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI, United States.,Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States
| | - Audrey P Gasch
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States.,Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, United States
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15
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Li Y, Zhang K, Liu J, Liu S, Nie C, Yan Y, Guan Y, Fan M, Qian H, Ying H, Wang L. Geniposide suppresses thermogenesis via regulating PKA catalytic subunit in adipocytes. Toxicology 2021; 464:153014. [PMID: 34718029 DOI: 10.1016/j.tox.2021.153014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/15/2021] [Accepted: 10/23/2021] [Indexed: 10/20/2022]
Abstract
Geniposide has been widely found to ameliorate many metabolic diseases. The recruitment and activation of brown/beige adipocytes are effective and promising methods for counteracting obesity and related diseases. However, the effect of geniposide on thermogenesis of adipocytes and its underlying mechanism have not yet been investigated. Here, we demonstrate that geniposide (25 mg/kg) reduces body temperature and cold tolerance of mice via suppressing thermogenic genes in interscapular brown adipose tissue (iBAT) and inguinal white adipose tissue (iWAT). Consistently, geniposide (20 mg/mL) suppresses thermogenic capacity of adipocytes (brown adipocytes and 3T3L1 preadipocyte cells) in vitro. Mechanistically, geniposide reduces the level of protein kinase A (PKA) catalytic subunit and further suppresses transcription activity and protein stability of uncoupling protein 1 (UCP1), leading to reduction of thermogenic capacity in adipocytes. Moreover, pharmacological PKA activation reverses geniposide-induced UCP1 inhibition, which indicated that geniposide suppresses thermogenesis of adipocytes via regulating PKA signaling. Together, our findings suggest that geniposide is an inhibitor of fat thermogenesis, establishing a novel function characteristic of geniposide.
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Affiliation(s)
- Yan Li
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Kuiliang Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Jinxin Liu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Shengnan Liu
- Chinese Academy of Sciences Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
| | - Chenzhipeng Nie
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Ying Yan
- Chinese Academy of Sciences Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
| | - Yanming Guan
- China National Research Institute of Food and Fermentation Industries Co. Ltd, Beijing 100015, China
| | - Mingcong Fan
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Haifeng Qian
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Hao Ying
- Chinese Academy of Sciences Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
| | - Li Wang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
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16
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Axonal CB1 Receptors Mediate Inhibitory Bouton Formation via cAMP Increase and PKA. J Neurosci 2021; 41:8279-8296. [PMID: 34413209 DOI: 10.1523/jneurosci.0851-21.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/30/2021] [Accepted: 07/25/2021] [Indexed: 12/11/2022] Open
Abstract
Experience-dependent formation and removal of inhibitory synapses are essential throughout life. For instance, GABAergic synapses are removed to facilitate learning, and strong excitatory activity is accompanied by the formation of inhibitory synapses to maintain coordination between excitation and inhibition. We recently discovered that active dendrites trigger the growth of inhibitory synapses via CB1 receptor-mediated endocannabinoid signaling, but the underlying mechanism remained unclear. Using two-photon microscopy to monitor the formation of individual inhibitory boutons in hippocampal organotypic slices from mice (both sexes), we found that CB1 receptor activation mediated the formation of inhibitory boutons and promoted their subsequent stabilization. Inhibitory bouton formation did not require neuronal activity and was independent of Gi/o-protein signaling, but was directly induced by elevating cAMP levels using forskolin and by activating Gs-proteins using DREADDs. Blocking PKA activity prevented CB1 receptor-mediated inhibitory bouton formation. Our findings reveal that axonal CB1 receptors signal via unconventional downstream pathways and that inhibitory bouton formation is triggered by an increase in axonal cAMP levels. Our results demonstrate an unexpected role for axonal CB1 receptors in axon-specific, and context-dependent, inhibitory synapse formation.SIGNIFICANCE STATEMENT Coordination between excitation and inhibition is required for proper brain function throughout life. It was previously shown that new inhibitory synapses can be formed in response to strong excitation to maintain this coordination, and this was mediated by endocannabinoid signaling via CB1 receptors. As activation of CB1 receptors generally results in the suppression of synaptic transmission, it remained unclear how CB1 receptors can mediate the formation of inhibitory synapses. Here we show that CB1 receptors on inhibitory axons signal via unconventional intracellular pathways and that inhibitory bouton formation is triggered by an increase in axonal cAMP levels and requires PKA activity. Our findings point to a central role for axonal cAMP signaling in activity-dependent inhibitory synapse formation.
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17
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Church TW, Tewatia P, Hannan S, Antunes J, Eriksson O, Smart TG, Hellgren Kotaleski J, Gold MG. AKAP79 enables calcineurin to directly suppress protein kinase A activity. eLife 2021; 10:e68164. [PMID: 34612814 PMCID: PMC8560092 DOI: 10.7554/elife.68164] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 10/04/2021] [Indexed: 12/28/2022] Open
Abstract
Interplay between the second messengers cAMP and Ca2+ is a hallmark of dynamic cellular processes. A common motif is the opposition of the Ca2+-sensitive phosphatase calcineurin and the major cAMP receptor, protein kinase A (PKA). Calcineurin dephosphorylates sites primed by PKA to bring about changes including synaptic long-term depression (LTD). AKAP79 supports signaling of this type by anchoring PKA and calcineurin in tandem. In this study, we discovered that AKAP79 increases the rate of calcineurin dephosphorylation of type II PKA regulatory subunits by an order of magnitude. Fluorescent PKA activity reporter assays, supported by kinetic modeling, show how AKAP79-enhanced calcineurin activity enables suppression of PKA without altering cAMP levels by increasing PKA catalytic subunit capture rate. Experiments with hippocampal neurons indicate that this mechanism contributes toward LTD. This non-canonical mode of PKA regulation may underlie many other cellular processes.
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Affiliation(s)
- Timothy W Church
- Department of Neuroscience, Physiology & Pharmacology, University College LondonLondonUnited Kingdom
| | - Parul Tewatia
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of TechnologyStockholmSweden
- Department of Neuroscience, Karolinska InstituteStockholmSweden
| | - Saad Hannan
- Department of Neuroscience, Physiology & Pharmacology, University College LondonLondonUnited Kingdom
| | - João Antunes
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of TechnologyStockholmSweden
| | - Olivia Eriksson
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of TechnologyStockholmSweden
| | - Trevor G Smart
- Department of Neuroscience, Physiology & Pharmacology, University College LondonLondonUnited Kingdom
| | - Jeanette Hellgren Kotaleski
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of TechnologyStockholmSweden
- Department of Neuroscience, Karolinska InstituteStockholmSweden
| | - Matthew G Gold
- Department of Neuroscience, Physiology & Pharmacology, University College LondonLondonUnited Kingdom
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18
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Massengill CI, Day-Cooney J, Mao T, Zhong H. Genetically encoded sensors towards imaging cAMP and PKA activity in vivo. J Neurosci Methods 2021; 362:109298. [PMID: 34339753 PMCID: PMC8659126 DOI: 10.1016/j.jneumeth.2021.109298] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 12/26/2022]
Abstract
Cyclic adenosine monophosphate (cAMP) is a universal second messenger that plays a crucial role in diverse biological functions, ranging from transcription to neuronal plasticity, and from development to learning and memory. In the nervous system, cAMP integrates inputs from many neuromodulators across a wide range of timescales - from seconds to hours - to modulate neuronal excitability and plasticity in brain circuits during different animal behavioral states. cAMP signaling events are both cell-specific and subcellularly compartmentalized. The same stimulus may result in different, sometimes opposite, cAMP dynamics in different cells or subcellular compartments. Additionally, the activity of protein kinase A (PKA), a major cAMP effector, is also spatiotemporally regulated. For these reasons, many laboratories have made great strides toward visualizing the intracellular dynamics of cAMP and PKA. To date, more than 80 genetically encoded sensors, including original and improved variants, have been published. It is starting to become possible to visualize cAMP and PKA signaling events in vivo, which is required to study behaviorally relevant cAMP/PKA signaling mechanisms. Despite significant progress, further developments are needed to enhance the signal-to-noise ratio and practical utility of these sensors. This review summarizes the recent advances and challenges in genetically encoded cAMP and PKA sensors with an emphasis on in vivo imaging in the brain during behavior.
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Affiliation(s)
| | - Julian Day-Cooney
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Tianyi Mao
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Haining Zhong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
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19
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Laviv T, Yasuda R. Imaging neuronal protein signaling dynamics in vivo. Curr Opin Neurobiol 2021; 69:68-75. [PMID: 33684848 PMCID: PMC8387335 DOI: 10.1016/j.conb.2021.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/31/2021] [Accepted: 02/05/2021] [Indexed: 11/16/2022]
Abstract
The activity patterns of Individual neurons are highly coordinated and synchronized within neuronal circuits in the brain, much like individual orchestra tools playing together to achieve harmony. Inside neurons, complex protein signaling cascades provide the molecular notes and instructions to each neuron. However, until recently, the dynamic nature of intracellular protein signaling in the intact brain has been eluded. In this review, we focus on recent advancements and the development of approaches to study neuronal signaling dynamics in vivo. We will discuss approaches for the implementation of biosensors for monitoring of protein signaling activities at the levels of individual synapses, dendritic branches, cell-wide neuromodulation, and transcription in the nucleus. Future improvement in these methods and their utilization will undoubtedly yield new insights regarding the intricate link between functional and molecular neuronal dynamics and how they underlie animal's behavior.
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Affiliation(s)
- Tal Laviv
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel.
| | - Ryohei Yasuda
- Department of Neuronal Signal Transduction, Max Planck Institute for Neuroscience, Jupiter, FL, 33458, USA.
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20
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Myristoylation alone is sufficient for PKA catalytic subunits to associate with the plasma membrane to regulate neuronal functions. Proc Natl Acad Sci U S A 2021; 118:2021658118. [PMID: 33876760 DOI: 10.1073/pnas.2021658118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Myristoylation is a posttranslational modification that plays diverse functional roles in many protein species. The myristate moiety is considered insufficient for protein-membrane associations unless additional membrane-affinity motifs, such as a stretch of positively charged residues, are present. Here, we report that the electrically neutral N-terminal fragment of the protein kinase A catalytic subunit (PKA-C), in which myristoylation is the only functional motif, is sufficient for membrane association. This myristoylation can associate a fraction of PKA-C molecules or fluorescent proteins (FPs) to the plasma membrane in neuronal dendrites. The net neutral charge of the PKA-C N terminus is evolutionally conserved, even though its membrane affinity can be readily tuned by changing charges near the myristoylation site. The observed membrane association, while moderate, is sufficient to concentrate PKA activity at the membrane by nearly 20-fold and is required for PKA regulation of AMPA receptors at neuronal synapses. Our results indicate that myristoylation may be sufficient to drive functionally significant membrane association in the absence of canonical assisting motifs. This provides a revised conceptual base for the understanding of how myristoylation regulates protein functions.
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21
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Arveseth CD, Happ JT, Hedeen DS, Zhu JF, Capener JL, Klatt Shaw D, Deshpande I, Liang J, Xu J, Stubben SL, Nelson IB, Walker MF, Kawakami K, Inoue A, Krogan NJ, Grunwald DJ, Hüttenhain R, Manglik A, Myers BR. Smoothened transduces Hedgehog signals via activity-dependent sequestration of PKA catalytic subunits. PLoS Biol 2021; 19:e3001191. [PMID: 33886552 PMCID: PMC8096101 DOI: 10.1371/journal.pbio.3001191] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 05/04/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
The Hedgehog (Hh) pathway is essential for organ development, homeostasis, and regeneration. Dysfunction of this cascade drives several cancers. To control expression of pathway target genes, the G protein-coupled receptor (GPCR) Smoothened (SMO) activates glioma-associated (GLI) transcription factors via an unknown mechanism. Here, we show that, rather than conforming to traditional GPCR signaling paradigms, SMO activates GLI by binding and sequestering protein kinase A (PKA) catalytic subunits at the membrane. This sequestration, triggered by GPCR kinase (GRK)-mediated phosphorylation of SMO intracellular domains, prevents PKA from phosphorylating soluble substrates, releasing GLI from PKA-mediated inhibition. Our work provides a mechanism directly linking Hh signal transduction at the membrane to GLI transcription in the nucleus. This process is more fundamentally similar between species than prevailing hypotheses suggest. The mechanism described here may apply broadly to other GPCR- and PKA-containing cascades in diverse areas of biology.
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Affiliation(s)
- Corvin D. Arveseth
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - John T. Happ
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Danielle S. Hedeen
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ju-Fen Zhu
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Jacob L. Capener
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Dana Klatt Shaw
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ishan Deshpande
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Jiahao Liang
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Jiewei Xu
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Sara L. Stubben
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Isaac B. Nelson
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Madison F. Walker
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Kouki Kawakami
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Nevan J. Krogan
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - David J. Grunwald
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ruth Hüttenhain
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Benjamin R. Myers
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
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22
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Olivieri C, Walker C, Karamafrooz A, Wang Y, Manu VS, Porcelli F, Blumenthal DK, Thomas DD, Bernlohr DA, Simon SM, Taylor SS, Veglia G. Defective internal allosteric network imparts dysfunctional ATP/substrate-binding cooperativity in oncogenic chimera of protein kinase A. Commun Biol 2021; 4:321. [PMID: 33692454 PMCID: PMC7946884 DOI: 10.1038/s42003-021-01819-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
An aberrant fusion of the DNAJB1 and PRKACA genes generates a chimeric protein kinase (PKA-CDNAJB1) in which the J-domain of the heat shock protein 40 is fused to the catalytic α subunit of cAMP-dependent protein kinase A (PKA-C). Deceivingly, this chimeric construct appears to be fully functional, as it phosphorylates canonical substrates, forms holoenzymes, responds to cAMP activation, and recognizes the endogenous inhibitor PKI. Nonetheless, PKA-CDNAJB1 has been recognized as the primary driver of fibrolamellar hepatocellular carcinoma and is implicated in other neoplasms for which the molecular mechanisms remain elusive. Here we determined the chimera's allosteric response to nucleotide and pseudo-substrate binding. We found that the fusion of the dynamic J-domain to PKA-C disrupts the internal allosteric network, causing dramatic attenuation of the nucleotide/PKI binding cooperativity. Our findings suggest that the reduced allosteric cooperativity exhibited by PKA-CDNAJB1 alters specific recognitions and interactions between substrates and regulatory partners contributing to dysregulation.
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Affiliation(s)
- Cristina Olivieri
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Caitlin Walker
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Adak Karamafrooz
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Yingjie Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Chemistry, University of Minnesota, Minneapolis, MN, USA
- Shenzhen Bay Laboratory, Shenzhen, China
| | - V S Manu
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Fernando Porcelli
- DIBAF - University of Tuscia - Largo dell' Università, Viterbo, Italy
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - David A Bernlohr
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Sanford M Simon
- Laboratory of Cellular Biophysics, Rockefeller University, New York, NY, USA
| | - Susan S Taylor
- Department of Chemistry and Biochemistry and Pharmacology, University of California at San Diego, La Jolla, CA, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA.
- Chemistry, University of Minnesota, Minneapolis, MN, USA.
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Zhang J, Zhang C, Chen X, Wang B, Ma W, Yang Y, Zheng R, Huang Z. PKA-RIIβ autophosphorylation modulates PKA activity and seizure phenotypes in mice. Commun Biol 2021; 4:263. [PMID: 33649504 PMCID: PMC7921646 DOI: 10.1038/s42003-021-01748-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 12/22/2020] [Indexed: 11/20/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is one of the most common and intractable neurological disorders in adults. Dysfunctional PKA signaling is causally linked to the TLE. However, the mechanism underlying PKA involves in epileptogenesis is still poorly understood. In the present study, we found the autophosphorylation level at serine 114 site (serine 112 site in mice) of PKA-RIIβ subunit was robustly decreased in the epileptic foci obtained from both surgical specimens of TLE patients and seizure model mice. The p-RIIβ level was negatively correlated with the activities of PKA. Notably, by using a P-site mutant that cannot be autophosphorylated and thus results in the released catalytic subunit to exert persistent phosphorylation, an increase in PKA activities through transduction with AAV-RIIβ-S112A in hippocampal DG granule cells decreased mIPSC frequency but not mEPSC, enhanced neuronal intrinsic excitability and seizure susceptibility. In contrast, a reduction of PKA activities by RIIβ knockout led to an increased mIPSC frequency, a reduction in neuronal excitability, and mice less prone to experimental seizure onset. Collectively, our data demonstrated that the autophosphorylation of RIIβ subunit plays a critical role in controlling neuronal and network excitabilities by regulating the activities of PKA, providing a potential therapeutic target for TLE.
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Affiliation(s)
- Jingliang Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Chenyu Zhang
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xiaoling Chen
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Bingwei Wang
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Weining Ma
- Department of Neurology, Shengjing Hospital Affiliated to China Medical University, Shenyang, China
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, IN, USA
| | - Ruimao Zheng
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
- Neuroscience Research Institute, Peking University, Beijing, China.
- Key Laboratory for Neuroscience, Ministry of Education, Beijing, China.
- Key Laboratory for Neuroscience of National Health Commission, Beijing, China.
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China.
- Key Laboratory for Neuroscience, Ministry of Education, Beijing, China.
- Key Laboratory for Neuroscience of National Health Commission, Beijing, China.
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Kopinke D, Norris AM, Mukhopadhyay S. Developmental and regenerative paradigms of cilia regulated hedgehog signaling. Semin Cell Dev Biol 2021; 110:89-103. [PMID: 32540122 PMCID: PMC7736055 DOI: 10.1016/j.semcdb.2020.05.029] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/25/2020] [Accepted: 05/29/2020] [Indexed: 01/08/2023]
Abstract
Primary cilia are immotile appendages that have evolved to receive and interpret a variety of different extracellular cues. Cilia play crucial roles in intercellular communication during development and defects in cilia affect multiple tissues accounting for a heterogeneous group of human diseases called ciliopathies. The Hedgehog (Hh) signaling pathway is one of these cues and displays a unique and symbiotic relationship with cilia. Not only does Hh signaling require cilia for its function but the majority of the Hh signaling machinery is physically located within the cilium-centrosome complex. More specifically, cilia are required for both repressing and activating Hh signaling by modifying bifunctional Gli transcription factors into repressors or activators. Defects in balancing, interpreting or establishing these repressor/activator gradients in Hh signaling either require cilia or phenocopy disruption of cilia. Here, we will summarize the current knowledge on how spatiotemporal control of the molecular machinery of the cilium allows for a tight control of basal repression and activation states of the Hh pathway. We will then discuss several paradigms on how cilia influence Hh pathway activity in tissue morphogenesis during development. Last, we will touch on how cilia and Hh signaling are being reactivated and repurposed during adult tissue regeneration. More specifically, we will focus on mesenchymal stem cells within the connective tissue and discuss the similarities and differences of how cilia and ciliary Hh signaling control the formation of fibrotic scar and adipose tissue during fatty fibrosis of several tissues.
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Affiliation(s)
- Daniel Kopinke
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA.
| | - Alessandra M Norris
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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25
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Lu TW, Aoto PC, Weng JH, Nielsen C, Cash JN, Hall J, Zhang P, Simon SM, Cianfrocco MA, Taylor SS. Structural analyses of the PKA RIIβ holoenzyme containing the oncogenic DnaJB1-PKAc fusion protein reveal protomer asymmetry and fusion-induced allosteric perturbations in fibrolamellar hepatocellular carcinoma. PLoS Biol 2020; 18:e3001018. [PMID: 33370777 PMCID: PMC7793292 DOI: 10.1371/journal.pbio.3001018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 01/08/2021] [Accepted: 12/18/2020] [Indexed: 12/31/2022] Open
Abstract
When the J-domain of the heat shock protein DnaJB1 is fused to the catalytic (C) subunit of cAMP-dependent protein kinase (PKA), replacing exon 1, this fusion protein, J-C subunit (J-C), becomes the driver of fibrolamellar hepatocellular carcinoma (FL-HCC). Here, we use cryo-electron microscopy (cryo-EM) to characterize J-C bound to RIIβ, the major PKA regulatory (R) subunit in liver, thus reporting the first cryo-EM structure of any PKA holoenzyme. We report several differences in both structure and dynamics that could not be captured by the conventional crystallography approaches used to obtain prior structures. Most striking is the asymmetry caused by the absence of the second cyclic nucleotide binding (CNB) domain and the J-domain in one of the RIIβ:J-C protomers. Using molecular dynamics (MD) simulations, we discovered that this asymmetry is already present in the wild-type (WT) RIIβ2C2 but had been masked in the previous crystal structure. This asymmetry may link to the intrinsic allosteric regulation of all PKA holoenzymes and could also explain why most disease mutations in PKA regulatory subunits are dominant negative. The cryo-EM structure, combined with small-angle X-ray scattering (SAXS), also allowed us to predict the general position of the Dimerization/Docking (D/D) domain, which is essential for localization and interacting with membrane-anchored A-Kinase-Anchoring Proteins (AKAPs). This position provides a multivalent mechanism for interaction of the RIIβ holoenzyme with membranes and would be perturbed in the oncogenic fusion protein. The J-domain also alters several biochemical properties of the RIIβ holoenzyme: It is easier to activate with cAMP, and the cooperativity is reduced. These results provide new insights into how the finely tuned allosteric PKA signaling network is disrupted by the oncogenic J-C subunit, ultimately leading to the development of FL-HCC.
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Affiliation(s)
- Tsan-Wen Lu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, United States of America
| | - Phillip C. Aoto
- Department of Pharmacology, University of California, San Diego, La Jolla, California, United States of America
| | - Jui-Hung Weng
- Department of Pharmacology, University of California, San Diego, La Jolla, California, United States of America
| | - Cole Nielsen
- Department of Pharmacology, University of California, San Diego, La Jolla, California, United States of America
| | - Jennifer N. Cash
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - James Hall
- Department of Pharmacology, University of California, San Diego, La Jolla, California, United States of America
| | - Ping Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California, United States of America
| | - Sanford M. Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York, United States of America
| | - Michael A. Cianfrocco
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Susan S. Taylor
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, United States of America
- Department of Pharmacology, University of California, San Diego, La Jolla, California, United States of America
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26
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Omar MH, Scott JD. AKAP Signaling Islands: Venues for Precision Pharmacology. Trends Pharmacol Sci 2020; 41:933-946. [PMID: 33082006 DOI: 10.1016/j.tips.2020.09.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/21/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022]
Abstract
Regulatory enzymes often have different roles in distinct subcellular compartments. Yet, most drugs indiscriminately saturate the cell. Thus, subcellular drug-delivery holds promise as a means to reduce off-target pharmacological effects. A-kinase anchoring proteins (AKAPs) sequester combinations of signaling enzymes within subcellular microdomains. Targeting drugs to these 'signaling islands' offers an opportunity for more precise delivery of therapeutics. Here, we review mechanisms that bestow protein kinase A (PKA) versatility inside the cell, appraise recent advances in exploiting AKAPs as platforms for precision pharmacology, and explore the impact of methodological innovations on AKAP research.
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Affiliation(s)
- Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA.
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27
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Zhang JZ, Lu TW, Stolerman LM, Tenner B, Yang JR, Zhang JF, Falcke M, Rangamani P, Taylor SS, Mehta S, Zhang J. Phase Separation of a PKA Regulatory Subunit Controls cAMP Compartmentation and Oncogenic Signaling. Cell 2020; 182:1531-1544.e15. [PMID: 32846158 PMCID: PMC7502557 DOI: 10.1016/j.cell.2020.07.043] [Citation(s) in RCA: 150] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 03/30/2020] [Accepted: 07/30/2020] [Indexed: 12/25/2022]
Abstract
The fidelity of intracellular signaling hinges on the organization of dynamic activity architectures. Spatial compartmentation was first proposed over 30 years ago to explain how diverse G protein-coupled receptors achieve specificity despite converging on a ubiquitous messenger, cyclic adenosine monophosphate (cAMP). However, the mechanisms responsible for spatially constraining this diffusible messenger remain elusive. Here, we reveal that the type I regulatory subunit of cAMP-dependent protein kinase (PKA), RIα, undergoes liquid-liquid phase separation (LLPS) as a function of cAMP signaling to form biomolecular condensates enriched in cAMP and PKA activity, critical for effective cAMP compartmentation. We further show that a PKA fusion oncoprotein associated with an atypical liver cancer potently blocks RIα LLPS and induces aberrant cAMP signaling. Loss of RIα LLPS in normal cells increases cell proliferation and induces cell transformation. Our work reveals LLPS as a principal organizer of signaling compartments and highlights the pathological consequences of dysregulating this activity architecture.
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Affiliation(s)
- Jason Z Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tsan-Wen Lu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lucas M Stolerman
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Brian Tenner
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jessica R Yang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jin-Fan Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Martin Falcke
- Mathematical Cell Physiology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany; Department of Physics, Humboldt University, 12489 Berlin, Germany
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan S Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA; Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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28
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Yuan M, Song ZH, Ying MD, Zhu H, He QJ, Yang B, Cao J. N-myristoylation: from cell biology to translational medicine. Acta Pharmacol Sin 2020; 41:1005-1015. [PMID: 32203082 PMCID: PMC7468318 DOI: 10.1038/s41401-020-0388-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 02/20/2020] [Indexed: 02/07/2023] Open
Abstract
Various lipids and lipid metabolites are bound to and modify the proteins in eukaryotic cells, which are known as ‘protein lipidation’. There are four major types of the protein lipidation, i.e. myristoylation, palmitoylation, prenylation, and glycosylphosphatidylinositol anchor. N-myristoylation refers to the attachment of 14-carbon fatty acid myristates to the N-terminal glycine of proteins by N-myristoyltransferases (NMT) and affects their physiology such as plasma targeting, subcellular tracking and localization, thereby influencing the function of proteins. With more novel pathogenic N-myristoylated proteins are identified, the N-myristoylation will attract great attentions in various human diseases including infectious diseases, parasitic diseases, and cancers. In this review, we summarize the current understanding of N-myristoylation in physiological processes and discuss the hitherto implication of crosstalk between N-myristoylation and other protein modification. Furthermore, we mention several well-studied NMT inhibitors mainly in infectious diseases and cancers and generalize the relation of NMT and cancer progression by browsing the clinic database. This review also aims to highlight the further investigation into the dynamic crosstalk of N-myristoylation in physiological processes as well as the potential application of protein N-myristoylation in translational medicine.
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29
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Rational Design of a Protein Kinase A Nuclear-cytosol Translocation Reporter. Sci Rep 2020; 10:9365. [PMID: 32518322 PMCID: PMC7283302 DOI: 10.1038/s41598-020-66349-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 05/11/2020] [Indexed: 12/14/2022] Open
Abstract
Protein Kinase A (PKA) exists as a tetrameric holoenzyme which activates with increase of cAMP and plays an important role in many physiological processes including cardiac physiology, neuronal development, and adipocyte function. Although this kinase has been the subject of numerous biosensor designs, a single-fluorophore reporter that performs comparably to Förster resonance energy transfer (FRET) has not yet been reported. Here, we have used basic observations of electrostatic interactions in PKA substrate recognition mechanism and nucleus localization sequence motif to design a phosphorylation switch that shuttles between the cytosol and the nucleus, a strategy that should be generalizable to all basophilic kinases. The resulting reporter yielded comparable kinetics and dynamic range to the PKA FRET reporter, AKAR3EV. We also performed basic characterization and demonstrated its potential use in monitoring multiple signaling molecules inside cells using basic fluorescence microscopy. Due to the single-fluorophore nature of this reporter, we envision that this could find broad applications in studies involving single cell analysis of PKA activity.
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Mucignat-Caretta C, Caretta A. Protein Kinase A Catalytic and Regulatory Subunits Interact Differently in Various Areas of Mouse Brain. Int J Mol Sci 2020; 21:ijms21093051. [PMID: 32357495 PMCID: PMC7246855 DOI: 10.3390/ijms21093051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/17/2020] [Accepted: 04/24/2020] [Indexed: 12/29/2022] Open
Abstract
Protein kinase A (PKA) are tetramers of two catalytic and two regulatory subunits, docked at precise intracellular sites to provide localized phosphorylating activity, triggered by cAMP binding to regulatory subunits and subsequent dissociation of catalytic subunits. It is unclear whether in the brain PKA dissociated subunits may also be found. PKA catalytic subunit was examined in various mouse brain areas using immunofluorescence, equilibrium binding and western blot, to reveal its location in comparison to regulatory subunits type RI and RII. In the cerebral cortex, catalytic subunits colocalized with clusters of RI, yet not all RI clusters were bound to catalytic subunits. In stria terminalis, catalytic subunits were in proximity to RI but separated from them. Catalytic subunits clusters were also present in the corpus striatum, where RII clusters were detected, whereas RI clusters were absent. Upon cAMP addition, the distribution of regulatory subunits did not change, while catalytic subunits were completely released from regulatory subunits. Unpredictably, catalytic subunits were not solubilized; instead, they re-targeted to other binding sites within the tissue, suggesting local macromolecular reorganization. Hence, the interactions between catalytic and regulatory subunits of protein kinase A consistently vary in different brain areas, supporting the idea of multiple interaction patterns.
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Affiliation(s)
- Carla Mucignat-Caretta
- Department of Molecular Medicine, University of Padova, 35131 Padova, Italy
- Biostructures and Biosystems National Institute, 00136 Roma, Italy
- Correspondence:
| | - Antonio Caretta
- Biostructures and Biosystems National Institute, 00136 Roma, Italy
- Department of Food and Drug, University of Parma, 43100 Parma, Italy
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31
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Swimming regulations for protein kinase A catalytic subunit. Biochem Soc Trans 2020; 47:1355-1366. [PMID: 31671183 DOI: 10.1042/bst20190230] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/05/2019] [Accepted: 09/10/2019] [Indexed: 11/17/2022]
Abstract
cAMP-dependent protein kinase (PKA) plays a central role in important biological processes including synaptic plasticity and sympathetic stimulation of the heart. Elevations of cAMP trigger release of PKA catalytic (C) subunits from PKA holoenzymes, thereby coupling cAMP to protein phosphorylation. Uncontrolled C subunit activity, such as occurs in genetic disorders in which regulatory subunits are depleted, is pathological. Anchoring proteins that associate with PKA regulatory subunits are important for localising PKA activity in cells. However, anchoring does not directly explain how unrestrained 'free swimming' of C subunits is avoided following C subunit release. In this review, I discuss new mechanisms that have been posited to account for this old problem. One straightforward explanation is that cAMP does not trigger C subunit dissociation but instead activates intact PKA holoenzymes whose activity is restrained through anchoring. A comprehensive comparison of observations for and against cAMP-activation of intact PKA holoenzymes does not lend credence to this mechanism. Recent measurements have revealed that PKA regulatory subunits are expressed at very high concentrations, and in large molar excess relative to C subunits. I discuss the implications of these skewed PKA subunit concentrations, before considering how phosphorylation of type II regulatory subunits and myristylation of C subunits are likely to contribute to controlling C subunit diffusion and recapture in cells. Finally, I speculate on future research directions that may be pursued on the basis of these emerging mechanisms.
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Cilleros-Mañé V, Just-Borràs L, Tomàs M, Garcia N, Tomàs JM, Lanuza MA. The M 2 muscarinic receptor, in association to M 1 , regulates the neuromuscular PKA molecular dynamics. FASEB J 2020; 34:4934-4955. [PMID: 32052889 DOI: 10.1096/fj.201902113r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 12/23/2019] [Accepted: 01/20/2020] [Indexed: 01/13/2023]
Abstract
Muscarinic acetylcholine receptor 1 subtype (M1 ) and muscarinic acetylcholine receptor 2 subtype (M2 ) presynaptic muscarinic receptor subtypes increase and decrease, respectively, neurotransmitter release at neuromuscular junctions. M2 involves protein kinase A (PKA), although the muscarinic regulation to form and inactivate the PKA holoenzyme is unknown. Here, we show that M2 signaling inhibits PKA by downregulating Cβ subunit, upregulating RIIα/β and liberating RIβ and RIIα to the cytosol. This promotes PKA holoenzyme formation and reduces the phosphorylation of the transmitter release target synaptosome-associated protein 25 and the gene regulator cAMP response element binding. Instead, M1 signaling, which is downregulated by M2 , opposes to M2 by recruiting R subunits to the membrane. The M1 and M2 reciprocal actions are performed through the anchoring protein A kinase anchor protein 150 as a common node. Interestingly, M2 modulation on protein expression needs M1 signaling. Altogether, these results describe the dynamics of PKA subunits upon M2 muscarinic signaling in basal and under presynaptic nerve activity, uncover a specific involvement of the M1 receptor and reveal the M1 /M2 balance to activate PKA to regulate neurotransmission. This provides a molecular mechanism to the PKA holoenzyme formation and inactivation which could be general to other synapses and cellular models.
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Affiliation(s)
- Víctor Cilleros-Mañé
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Departament de Ciències Mèdiques Bàsiques, Universitat Rovira i Virgili, Reus, Spain
| | - Laia Just-Borràs
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Departament de Ciències Mèdiques Bàsiques, Universitat Rovira i Virgili, Reus, Spain
| | - Marta Tomàs
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Departament de Ciències Mèdiques Bàsiques, Universitat Rovira i Virgili, Reus, Spain
| | - Neus Garcia
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Departament de Ciències Mèdiques Bàsiques, Universitat Rovira i Virgili, Reus, Spain
| | - Josep Maria Tomàs
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Departament de Ciències Mèdiques Bàsiques, Universitat Rovira i Virgili, Reus, Spain
| | - Maria Angel Lanuza
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Departament de Ciències Mèdiques Bàsiques, Universitat Rovira i Virgili, Reus, Spain
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Guruceaga X, Perez-Cuesta U, Abad-Diaz de Cerio A, Gonzalez O, Alonso RM, Hernando FL, Ramirez-Garcia A, Rementeria A. Fumagillin, a Mycotoxin of Aspergillus fumigatus: Biosynthesis, Biological Activities, Detection, and Applications. Toxins (Basel) 2019; 12:E7. [PMID: 31861936 PMCID: PMC7020470 DOI: 10.3390/toxins12010007] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 12/26/2022] Open
Abstract
Fumagillin is a mycotoxin produced, above all, by the saprophytic filamentous fungus Aspergillus fumigatus. This mold is an opportunistic pathogen that can cause invasive aspergillosis, a disease that has high mortality rates linked to it. Its ability to adapt to environmental stresses through the production of secondary metabolites, including several mycotoxins (gliotoxin, fumagillin, pseurotin A, etc.) also seem to play an important role in causing these infections. Since the discovery of the A. fumigatus fumagillin in 1949, many studies have focused on this toxin and in this review we gather all the information currently available. First of all, the structural characteristics of this mycotoxin and the different methods developed for its determination are given in detail. Then, the biosynthetic gene cluster and the metabolic pathway involved in its production and regulation are explained. The activity of fumagillin on its target, the methionine aminopeptidase type 2 (MetAP2) enzyme, and the effects of blocking this enzyme in the host are also described. Finally, the applications that this toxin and its derivatives have in different fields, such as the treatment of cancer and its microsporicidal activity in the treatment of honeybee hive infections with Nosema spp., are reviewed. Therefore, this work offers a complete review of all the information currently related to the fumagillin mycotoxin secreted by A. fumigatus, important because of its role in the fungal infection process but also because it has many other applications, notably in beekeeping, the treatment of infectious diseases, and in oncology.
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Affiliation(s)
- Xabier Guruceaga
- Fungal and Bacterial Biomics Research Group, Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (X.G.); (U.P.-C.); (A.A.-D.d.C.); (F.L.H.)
| | - Uxue Perez-Cuesta
- Fungal and Bacterial Biomics Research Group, Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (X.G.); (U.P.-C.); (A.A.-D.d.C.); (F.L.H.)
| | - Ana Abad-Diaz de Cerio
- Fungal and Bacterial Biomics Research Group, Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (X.G.); (U.P.-C.); (A.A.-D.d.C.); (F.L.H.)
| | - Oskar Gonzalez
- FARMARTEM Group, Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (O.G.); (R.M.A.)
| | - Rosa M. Alonso
- FARMARTEM Group, Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (O.G.); (R.M.A.)
| | - Fernando Luis Hernando
- Fungal and Bacterial Biomics Research Group, Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (X.G.); (U.P.-C.); (A.A.-D.d.C.); (F.L.H.)
| | - Andoni Ramirez-Garcia
- Fungal and Bacterial Biomics Research Group, Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (X.G.); (U.P.-C.); (A.A.-D.d.C.); (F.L.H.)
| | - Aitor Rementeria
- Fungal and Bacterial Biomics Research Group, Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; (X.G.); (U.P.-C.); (A.A.-D.d.C.); (F.L.H.)
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A strategy to identify protein-N-myristoylation-dependent phosphorylation reactions of cellular proteins by using Phos-tag SDS-PAGE. PLoS One 2019; 14:e0225510. [PMID: 31751425 PMCID: PMC6872159 DOI: 10.1371/journal.pone.0225510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/06/2019] [Indexed: 11/21/2022] Open
Abstract
To establish a strategy for identifying protein-N-myristoylation-dependent phosphorylation of cellular proteins, Phos-tag SDS-PAGE was performed on wild-type (WT) and nonmyristoylated mutant (G2A-mutant) FMNL2 and FMNL3, phosphorylated N-myristoylated model proteins expressed in HEK293 cells. The difference in the banding pattern in Phos-tag SDS-PAGE between the WT and G2A-mutant FMNL2 indicated the presence of N-myristoylation-dependent phosphorylation sites in FMNL2. Phos-tag SDS-PAGE of FMNL2 mutants in which the putative phosphorylation sites listed in PhosphoSitePlus (an online database of phosphorylation sites) were changed to Ala revealed that Ser-171 and Ser-1072 are N-myristoylation-dependent phosphorylation sites in FMNL2. Similar experiments with FMNL3 demonstrated that N-myristoylation-dependent phosphorylation occurs at a single Ser residue at position 174, which is a Ser residue conserved between FMNL2 and FMNL3, corresponding to Ser-171 in FMNL2. The facts that phosphorylation of Ser-1072 in FMNL2 has been shown to play a critical role in integrin β1 internalization mediated by FMNL2 and that Ser-171 in FMNL2 and Ser-174 in FMNL3 are novel putative phosphorylation sites conserved between FMNL2 and FMNL3 indicate that the strategy used in this study is a useful tool for identifying and characterizing physiologically important phosphorylation reactions occurring on N-myristoylated proteins.
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Ohadi D, Rangamani P. Geometric Control of Frequency Modulation of cAMP Oscillations due to Calcium in Dendritic Spines. Biophys J 2019; 117:1981-1994. [PMID: 31668747 PMCID: PMC7018999 DOI: 10.1016/j.bpj.2019.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 12/12/2022] Open
Abstract
The spatiotemporal regulation of cyclic adenosine monophosphate (cAMP) and its dynamic interactions with other second messengers such as calcium are critical features of signaling specificity required for neuronal development and connectivity. cAMP is known to contribute to long-term potentiation and memory formation by controlling the formation and regulation of dendritic spines. Despite the recent advances in biosensing techniques for monitoring spatiotemporal cAMP dynamics, the underlying molecular mechanisms that attribute to the subcellular modulation of cAMP remain unknown. In this work, we model the spatiotemporal dynamics of calcium-induced cAMP signaling pathway in dendritic spines. Using a three-dimensional reaction-diffusion model, we investigate the effect of different spatial characteristics of cAMP dynamics that may be responsible for subcellular regulation of cAMP concentrations. Our model predicts that the volume/surface ratio of the spine, regulated through the spine head size, spine neck size, and the presence of physical barriers (spine apparatus), is an important regulator of cAMP dynamics. Furthermore, localization of the enzymes responsible for the synthesis and degradation of cAMP in different compartments also modulates the oscillatory patterns of cAMP through exponential relationships. Our findings shed light on the significance of complex geometric and localization relationships for cAMP dynamics in dendritic spines.
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Affiliation(s)
- Donya Ohadi
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California.
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PKAc-directed interaction and phosphorylation of Ptc is required for Hh signaling inhibition in Drosophila. Cell Discov 2019; 5:44. [PMID: 31636957 PMCID: PMC6796939 DOI: 10.1038/s41421-019-0112-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/04/2019] [Indexed: 01/20/2023] Open
Abstract
Ptc is a gatekeeper to avoid abnormal Hh signaling activation, but the key regulators involved in Ptc-mediated inhibition remain largely unknown. Here, we identify PKAc as a key regulator required for Ptc inhibitory function. In the absence of Hh, PKAc physically interacts with Ptc and phosphorylates Ptc at Ser-1150 and -1183 residues. The presence of Hh unleashes PKAc from Ptc and activates Hh signaling. By combining both in vitro and in vivo functional assays, we demonstrate that such Ptc–PKAc interaction and Ptc phosphorylation are both important for Ptc inhibitory function. Interestingly, we further demonstrate that PKAc is subjected to palmitoylation, contributing to its kinase activity on plasma membrane. Based on those novel findings, we establish a working model on Ptc inhibitory function: In the absence of Hh, PKAc interacts with and phosphorylates Ptc to ensure its inhibitory function; and Hh presence releases PKAc from Ptc, resulting in Hh signaling activation.
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Ohadi D, Schmitt DL, Calabrese B, Halpain S, Zhang J, Rangamani P. Computational Modeling Reveals Frequency Modulation of Calcium-cAMP/PKA Pathway in Dendritic Spines. Biophys J 2019; 117:1963-1980. [PMID: 31668749 PMCID: PMC7031750 DOI: 10.1016/j.bpj.2019.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022] Open
Abstract
Dendritic spines are the primary excitatory postsynaptic sites that act as subcompartments of signaling. Ca2+ is often the first and most rapid signal in spines. Downstream of calcium, the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway plays a critical role in the regulation of spine formation, morphological modifications, and ultimately, learning and memory. Although the dynamics of calcium are reasonably well-studied, calcium-induced cAMP/PKA dynamics, particularly with respect to frequency modulation, are not fully explored. In this study, we present a well-mixed model for the dynamics of calcium-induced cAMP/PKA dynamics in dendritic spines. The model is constrained using experimental observations in the literature. Further, we measured the calcium oscillation frequency in dendritic spines of cultured hippocampal CA1 neurons and used these dynamics as model inputs. Our model predicts that the various steps in this pathway act as frequency modulators for calcium, and the high frequency of calcium input is filtered by adenylyl cyclase 1 and phosphodiesterases in this pathway such that cAMP/PKA only responds to lower frequencies. This prediction has important implications for noise filtering and long-timescale signal transduction in dendritic spines. A companion manuscript presents a three-dimensional spatial model for the same pathway.
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Affiliation(s)
- Donya Ohadi
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California
| | - Danielle L Schmitt
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Barbara Calabrese
- Division of Biological Sciences and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California
| | - Shelley Halpain
- Division of Biological Sciences and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California
| | - Jin Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California.
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Lin W, Mehta S, Zhang J. Genetically encoded fluorescent biosensors illuminate kinase signaling in cancer. J Biol Chem 2019; 294:14814-14822. [PMID: 31434714 DOI: 10.1074/jbc.rev119.006177] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase signaling networks stringently regulate cellular processes, such as proliferation, motility, and cell survival. These networks are also central to the evolution and progression of cancer. Accordingly, genetically encoded fluorescent biosensors capable of directly illuminating the spatiotemporal dynamics of kinase signaling in live cells are being increasingly used to investigate kinase signaling in cancer cells and tumor tissue sections. These biosensors enable visualization of biological processes and events directly in situ, preserving the native biological context and providing detailed insight into their localization and dynamics in cells. Herein, we first review common design strategies for kinase activity biosensors, including signaling targets, biosensor components, and fluorescent proteins involved. Subsequently, we discuss applications of biosensors to study the biology and management of cancer. These versatile molecular tools have been deployed to study oncogenic kinase signaling in living cells and image kinase activities in tumors or to decipher the mechanisms of anticancer drugs. We anticipate that the diversity and precision of genetically encoded biosensors will expand their use to further unravel the dysregulation of kinase signaling in cancer and the modes of actions of cancer-targeting drugs.
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Affiliation(s)
- Wei Lin
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0702
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0702
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0702
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Jongbloets BC, Ma L, Mao T, Zhong H. Visualizing Protein Kinase A Activity In Head-fixed Behaving Mice Using In Vivo Two-photon Fluorescence Lifetime Imaging Microscopy. J Vis Exp 2019. [PMID: 31233029 DOI: 10.3791/59526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Neuromodulation exerts powerful control over brain function. Dysfunction of neuromodulatory systems results in neurological and psychiatric disorders. Despite their importance, technologies for tracking neuromodulatory events with cellular resolution are just beginning to emerge. Neuromodulators, such as dopamine, norepinephrine, acetylcholine, and serotonin, trigger intracellular signaling events via their respective G protein-coupled receptors to modulate neuronal excitability, synaptic communications, and other neuronal functions, thereby regulating information processing in the neuronal network. The above mentioned neuromodulators converge onto the cAMP/protein kinase A (PKA) pathway. Therefore, in vivo PKA imaging with single-cell resolution was developed as a readout for neuromodulatory events in a manner analogous to calcium imaging for neuronal electrical activities. Herein, a method is presented to visualize PKA activity at the level of individual neurons in the cortex of head-fixed behaving mice. To do so, an improved A-kinase activity reporter (AKAR), called tAKARα, is used, which is based on Förster resonance energy transfer (FRET). This genetically-encoded PKA sensor is introduced into the motor cortex via in utero electroporation (IUE) of DNA plasmids, or stereotaxic injection of adeno-associated virus (AAV). FRET changes are imaged using two-photon fluorescence lifetime imaging microscopy (2pFLIM), which offers advantages over ratiometric FRET measurements for quantifying FRET signal in light-scattering brain tissue. To study PKA activities during enforced locomotion, tAKARα is imaged through a chronic cranial window above the cortex of awake, head-fixed mice, which run or rest on a speed-controlled motorized treadmill. This imaging approach will be applicable to many other brain regions to study corresponding behavior-induced PKA activities and to other FLIM-based sensors for in vivo imaging.
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Affiliation(s)
| | - Lei Ma
- Vollum Institute, Oregon Health & Science University
| | - Tianyi Mao
- Vollum Institute, Oregon Health & Science University
| | - Haining Zhong
- Vollum Institute, Oregon Health & Science University;
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40
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Zhao LX, Ge YH, Li JB, Xiong CH, Law PY, Xu JR, Qiu Y, Chen HZ. M1 muscarinic receptors regulate the phosphorylation of AMPA receptor subunit GluA1 via a signaling pathway linking cAMP-PKA and PI3K-Akt. FASEB J 2019; 33:6622-6631. [PMID: 30794430 DOI: 10.1096/fj.201802351r] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
M1 muscarinic acetylcholine receptors are highly expressed in key areas that control cognition, such as the cortex and hippocampus, representing one potential therapeutic target for cognitive dysfunctions of Alzheimer's disease and schizophrenia. We have reported that M1 receptors facilitate cognition by promoting membrane insertion of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor AMPA receptor subunit 1 (GluA1) through phosphorylation at Ser845. However, the signaling pathway is still unclear. Here we showed that adenylyl cyclase inhibitor 2',5'-dideoxyadenosine and PKA inhibitor KT5720 inhibited enhancement of phosphorylation of Ser845 and membrane insertion of GluA1 induced by M1 receptor activation. Furthermore, PI3K inhibitor LY294002 and protein kinase B (Akt) inhibitor IV blocked the effects of M1 receptors as well. Remarkably, the increase of the activity of PI3K-Akt signaling induced by M1 receptor activation could be abolished by cAMP-PKA inhibitors. Moreover, inhibiting the mammalian target of rapamycin (mTOR) complex 1, an important downstream effector of PI3K-Akt, by short-term application of rapamycin attenuated the effects of M1 receptors on GluA1. Furthermore, such effect was unrelated to possible protein synthesis promoted by mTOR. Taken together, these data demonstrate that M1 receptor activation induces membrane insertion of GluA1 via a signaling linking cAMP-PKA and PI3K-Akt-mTOR pathways but is irrelevant to protein synthesis.-Zhao, L.-X., Ge, Y.-H., Li, J.-B., Xiong, C.-H., Law, P.-Y., Xu, J.-R., Qiu, Y., Chen, H.-Z. M1 muscarinic receptors regulate the phosphorylation of AMPA receptor subunit GluA1 via a signaling pathway linking cAMP-PKA and PI3K-Akt.
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Affiliation(s)
- Lan-Xue Zhao
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan-Hui Ge
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Bing Li
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Cai-Hong Xiong
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ping-Yee Law
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA; and
| | - Jian-Rong Xu
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yu Qiu
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hong-Zhuan Chen
- Institute of Interdisciplinary Integrative Biomedical Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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41
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Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 PMCID: PMC7462118 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 302] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
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Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
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42
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Ma L, Jongbloets BC, Xiong WH, Melander JB, Qin M, Lameyer TJ, Harrison MF, Zemelman BV, Mao T, Zhong H. A Highly Sensitive A-Kinase Activity Reporter for Imaging Neuromodulatory Events in Awake Mice. Neuron 2018; 99:665-679.e5. [PMID: 30100256 PMCID: PMC6152931 DOI: 10.1016/j.neuron.2018.07.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 06/01/2018] [Accepted: 07/11/2018] [Indexed: 01/01/2023]
Abstract
Neuromodulation imposes powerful control over brain function, and cAMP-dependent protein kinase (PKA) is a central downstream mediator of multiple neuromodulators. Although genetically encoded PKA sensors have been developed, single-cell imaging of PKA activity in living mice has not been established. Here, we used two-photon fluorescence lifetime imaging microscopy (2pFLIM) to visualize genetically encoded PKA sensors in response to the neuromodulators norepinephrine and dopamine. We screened available PKA sensors for 2pFLIM and further developed a variant (named tAKARα) with increased sensitivity and a broadened dynamic range. This sensor allowed detection of PKA activation by norepinephrine at physiologically relevant concentrations and kinetics, and by optogenetically released dopamine. In vivo longitudinal 2pFLIM imaging of tAKARα tracked bidirectional PKA activities in individual neurons in awake mice and revealed neuromodulatory PKA events that were associated with wakefulness, pharmacological manipulation, and locomotion. This new sensor combined with 2pFLIM will enable interrogation of neuromodulation-induced PKA signaling in awake animals. VIDEO ABSTRACT.
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Affiliation(s)
- Lei Ma
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Bart C Jongbloets
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Wei-Hong Xiong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Joshua B Melander
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Maozhen Qin
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Tess J Lameyer
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Madeleine F Harrison
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712, USA
| | - Boris V Zemelman
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tianyi Mao
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Haining Zhong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
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43
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Norris JL, Hughes RM. protaTETHER - a method for the incorporation of variable linkers in protein fusions reveals impacts of linker flexibility in a PKAc-GFP fusion protein. FEBS Open Bio 2018; 8:1029-1042. [PMID: 29928581 PMCID: PMC5986021 DOI: 10.1002/2211-5463.12414] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/12/2018] [Accepted: 03/01/2018] [Indexed: 11/11/2022] Open
Abstract
Protein fusions are of fundamental importance in the study of cellular biology and the elucidation of cell signaling pathways, and the importance of linkers for the proper function of protein fusions is well documented in the literature. However, there are few convenient methods available to experimentalists for the systematic implementation of linkers in protein fusions. In this work, we describe a universal approach to the creation and insertion of focused linker libraries into protein fusions. This process, deemed protaTETHER, utilizes reiterative oligomer design, PCR-mediated linker library generation, and restriction enzyme-free cloning methods in a straightforward, three-step cloning process. We utilize a fusion between the catalytic subunit of cAMP-dependent protein kinase A (PKAc) and green fluorescent protein (GFP) for the development of the protaTETHER method, implementing small linker libraries that vary by length, sequence, and predicted secondary structural elements. We analyze the impact of linker length and sequence on the expression, activity, and subcellular localization of the PKAc-GFP fusions, and use these results to select a PKAc-GFP fusion construct with robust expression and enzymatic activity. Based upon the results of both biochemical experiments and molecular modeling, we determine that linker flexibility is more important than linker length for optimal kinase activity and expression.
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44
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Blackwell KT, Salinas AG, Tewatia P, English B, Hellgren Kotaleski J, Lovinger DM. Molecular mechanisms underlying striatal synaptic plasticity: relevance to chronic alcohol consumption and seeking. Eur J Neurosci 2018; 49:768-783. [PMID: 29602186 DOI: 10.1111/ejn.13919] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 01/02/2023]
Abstract
The striatum, the input structure of the basal ganglia, is a major site of learning and memory for goal-directed actions and habit formation. Spiny projection neurons of the striatum integrate cortical, thalamic, and nigral inputs to learn associations, with cortico-striatal synaptic plasticity as a learning mechanism. Signaling molecules implicated in synaptic plasticity are altered in alcohol withdrawal, which may contribute to overly strong learning and increased alcohol seeking and consumption. To understand how interactions among signaling molecules produce synaptic plasticity, we implemented a mechanistic model of signaling pathways activated by dopamine D1 receptors, acetylcholine receptors, and glutamate. We use our novel, computationally efficient simulator, NeuroRD, to simulate stochastic interactions both within and between dendritic spines. Dopamine release during theta burst and 20-Hz stimulation was extrapolated from fast-scan cyclic voltammetry data collected in mouse striatal slices. Our results show that the combined activity of several key plasticity molecules correctly predicts the occurrence of either LTP, LTD, or no plasticity for numerous experimental protocols. To investigate spatial interactions, we stimulate two spines, either adjacent or separated on a 20-μm dendritic segment. Our results show that molecules underlying LTP exhibit spatial specificity, whereas 2-arachidonoylglycerol exhibits a spatially diffuse elevation. We also implement changes in NMDA receptors, adenylyl cyclase, and G protein signaling that have been measured following chronic alcohol treatment. Simulations under these conditions suggest that the molecular changes can predict changes in synaptic plasticity, thereby accounting for some aspects of alcohol use disorder.
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Affiliation(s)
- Kim T Blackwell
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA.,Department of Bioengineering, George Mason University, Fairfax, VA, USA
| | - Armando G Salinas
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA.,National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Parul Tewatia
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Brad English
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
| | - Jeanette Hellgren Kotaleski
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - David M Lovinger
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
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45
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Søberg K, Skålhegg BS. The Molecular Basis for Specificity at the Level of the Protein Kinase a Catalytic Subunit. Front Endocrinol (Lausanne) 2018; 9:538. [PMID: 30258407 PMCID: PMC6143667 DOI: 10.3389/fendo.2018.00538] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/24/2018] [Indexed: 12/16/2022] Open
Abstract
Assembly of multi enzyme complexes at subcellular localizations by anchoring- and scaffolding proteins represents a pivotal mechanism for achieving spatiotemporal regulation of cellular signaling after hormone receptor targeting [for review, see (1)]. In the 3' 5'-cyclic adenosine monophosphate (cAMP) dependent protein kinase (PKA) signaling pathway it is generally accepted that specificity is secured at several levels. This includes at the first level stimulation of receptors coupled to heterotrimeric G proteins which through stimulation of adenylyl cyclase (AC) forms the second messenger cAMP. Cyclic AMP has several receptors including PKA. PKA is a tetrameric holoenzyme consisting of a regulatory (R) subunit dimer and two catalytic (C) subunits. The R subunit is the receptor for cAMP and compartmentalizes cAMP signals through binding to cell and tissue-specifically expressed A kinase anchoring proteins (AKAPs). The current dogma tells that in the presence of cAMP, PKA dissociates into an R subunit dimer and two C subunits which are free to phosphorylate relevant substrates in the cytosol and nucleus. The release of the C subunit has raised the question how specificity of the cAMP and PKA signaling pathway is maintained when the C subunit no longer is attached to the R subunit-AKAP complex. An increasing body of evidence points toward a regulatory role of the cAMP and PKA signaling pathway by targeting the C subunits to various C subunit binding proteins in the cytosol and nucleus. Moreover, recent identification of isoform specific amino acid sequences, motifs and three dimensional structures have together provided new insight into how PKA at the level of the C subunit may act in a highly isoform-specific fashion. Here we discuss recent understanding of specificity of the cAMP and PKA signaling pathway based on C subunit subcellular targeting as well as evolution of the C subunit structure that may contribute to the dynamic regulation of C subunit activity.
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Affiliation(s)
- Kristoffer Søberg
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Bjørn Steen Skålhegg
- Section for Molecular Nutrition, University of Oslo, Oslo, Norway
- *Correspondence: Bjørn Steen Skålhegg
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46
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Yapo C, Nair AG, Hellgren Kotaleski J, Vincent P, Castro LRV. Switch-like PKA responses in the nucleus of striatal neurons. J Cell Sci 2018; 131:jcs.216556. [DOI: 10.1242/jcs.216556] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/25/2018] [Indexed: 12/25/2022] Open
Abstract
Although it is known that Protein Kinase A (PKA) in the nucleus regulates gene expression, the specificities of nuclear PKA signaling remain poorly understood. Here, we combined computational modeling and live-cell imaging of PKA-dependent phosphorylation in mouse brain slices to investigate how transient dopamine signals are translated into nuclear PKA activity in cortical pyramidal neurons and striatal medium spiny neurons. We observed that the nuclear PKA signal in striatal neurons featured an ultrasensitive responsiveness, associated with fast, all or none responses, which is not consistent with the commonly accepted theory of a slow and passive diffusion of catalytic PKA in the nucleus. Our numerical model suggests that a positive feed-forward mechanism inhibiting nuclear phosphatase activity - possibly mediated by DARPP-32 - could be responsible for this non-linear pattern of nuclear PKA response, allowing for a better detection of the transient dopamine signals that are often associated with reward-mediated learning.
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Affiliation(s)
- Cédric Yapo
- Sorbonne Université, CNRS, Biological Adaptation and Ageing, F-75005 Paris, France
- Member of the Bio-Psy Labex, France
| | - Anu G. Nair
- Science for Life Laboratory, School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, 10044, Sweden
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
- Manipal University, Manipal, India
| | - Jeanette Hellgren Kotaleski
- Science for Life Laboratory, School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, 10044, Sweden
- Department of Neuroscience, Karolinska Institutet, Solna, 17177, Sweden
| | - Pierre Vincent
- Sorbonne Université, CNRS, Biological Adaptation and Ageing, F-75005 Paris, France
- Member of the Bio-Psy Labex, France
| | - Liliana R. V. Castro
- Sorbonne Université, CNRS, Biological Adaptation and Ageing, F-75005 Paris, France
- Member of the Bio-Psy Labex, France
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47
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Mechanisms for restraining cAMP-dependent protein kinase revealed by subunit quantitation and cross-linking approaches. Proc Natl Acad Sci U S A 2017; 114:10414-10419. [PMID: 28893983 DOI: 10.1073/pnas.1701782114] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Protein phosphorylation by cyclic AMP-dependent protein kinase (PKA) underlies key cellular processes, including sympathetic stimulation of heart cells, and potentiation of synaptic strength in neurons. Unrestrained PKA activity is pathological, and an enduring challenge is to understand how the activity of PKA catalytic subunits is directed in cells. We developed a light-activated cross-linking approach to monitor PKA subunit interactions with temporal precision in living cells. This enabled us to refute the recently proposed theory that PKA catalytic subunits remain tethered to regulatory subunits during cAMP elevation. Instead, we have identified other features of PKA signaling for reducing catalytic subunit diffusion and increasing recapture rate. Comprehensive quantitative immunoblotting of protein extracts from human embryonic kidney cells and rat organs reveals that regulatory subunits are always in large molar excess of catalytic subunits (average ∼17-fold). In the majority of organs tested, type II regulatory (RII) subunits were found to be the predominant PKA subunit. We also examined the architecture of PKA complexes containing RII subunits using cross-linking coupled to mass spectrometry. Quantitative comparison of cross-linking within a complex of RIIβ and Cβ, with or without the prototypical anchoring protein AKAP18α, revealed that the dimerization and docking domain of RIIβ is between its second cAMP binding domains. This architecture is compatible with anchored RII subunits directing the myristylated N terminus of catalytic subunits toward the membrane for release and recapture within the plane of the membrane.
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Yasuda R. Biophysics of Biochemical Signaling in Dendritic Spines: Implications in Synaptic Plasticity. Biophys J 2017; 113:2152-2159. [PMID: 28866426 DOI: 10.1016/j.bpj.2017.07.029] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/12/2017] [Accepted: 07/20/2017] [Indexed: 11/24/2022] Open
Abstract
Dendritic spines are mushroom-shaped postsynaptic compartments that host biochemical signal cascades important for synaptic plasticity and, ultimately, learning and memory. Signaling events in spines involve a signaling network composed of hundreds of signaling proteins interacting with each other extensively. Synaptic plasticity is typically induced by Ca2+ elevation in spines, which activates a variety of signaling pathways. This leads to changes in the actin cytoskeleton and membrane dynamics, which in turn causes structural and functional changes of the spine. Recent studies have demonstrated that the activities of these proteins have a variety of spatiotemporal patterns, which orchestrate signaling activity in different subcellular compartments at different timescales. The diffusion and the decay kinetics of signaling molecules play important roles in determining the degree of their spatial spreading, and thereby the degree of the spine specificity of the signaling pathway.
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Affiliation(s)
- Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, Florida.
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