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Bock A, Irannejad R, Scott JD. cAMP signaling: a remarkably regional affair. Trends Biochem Sci 2024; 49:305-317. [PMID: 38310024 PMCID: PMC11175624 DOI: 10.1016/j.tibs.2024.01.004] [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: 11/02/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 02/05/2024]
Abstract
Louis Pasteur once famously said 'in the fields of observation chance favors only the prepared mind'. Much of chance is being in the right place at the right time. This is particularly true in the crowded molecular environment of the cell where being in the right place is often more important than timing. Although Brownian motion argues that enzymes will eventually bump into substrates, this probability is greatly enhanced if both molecules reside in the same subcellular compartment. However, activation of cell signaling enzymes often requires the transmission of chemical signals from extracellular stimuli to intracellular sites of action. This review highlights new developments in our understanding of cAMP generation and the 3D utilization of this second messenger inside cells.
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Affiliation(s)
- Andreas Bock
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany.
| | - Roshanak Irannejad
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - John D Scott
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA.
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2
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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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Lauer SM, Omar MH, Golkowski MG, Kenerson HL, Lee KS, Pascual BC, Lim HC, Forbush K, Smith FD, Gordan JD, Ong SE, Yeung RS, Scott JD. Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma. Cell Rep 2024; 43:113678. [PMID: 38236773 PMCID: PMC10964278 DOI: 10.1016/j.celrep.2024.113678] [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: 07/21/2023] [Revised: 11/23/2023] [Accepted: 01/02/2024] [Indexed: 01/30/2024] Open
Abstract
The DNAJ-PKAc fusion kinase is a defining feature of fibrolamellar carcinoma (FLC). FLC tumors are notoriously resistant to standard chemotherapies, with aberrant kinase activity assumed to be a contributing factor. By combining proximity proteomics, biochemical analyses, and live-cell photoactivation microscopy, we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates, including proteins involved in translation and the anti-apoptotic factor Bcl-2-associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Tissue samples from patients with FLC exhibit increased levels of BAG2 in primary and metastatic tumors. Furthermore, drug studies implicate the DNAJ-PKAc/Hsp70/BAG2 axis in potentiating chemotherapeutic resistance. We find that the Bcl-2 inhibitor navitoclax enhances sensitivity to etoposide-induced apoptosis in cells expressing DNAJ-PKAc. Thus, our work indicates BAG2 as a marker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.
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Affiliation(s)
- Sophia M Lauer
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Mitchell H Omar
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Martin G Golkowski
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Heidi L Kenerson
- Department of Surgery, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Kyung-Soon Lee
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Bryan C Pascual
- Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Huat C Lim
- Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Katherine Forbush
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - F Donelson Smith
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - John D Gordan
- Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Shao-En Ong
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Raymond S Yeung
- Department of Surgery, University of Washington Medical Center, Seattle, WA 98195, USA
| | - John D Scott
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA.
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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 (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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5
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Lauer SM, Omar MH, Golkowski MG, Kenerson HL, Pascual BC, Forbush K, Smith FD, Gordan J, Ong SE, Yeung RS, Scott JD. Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.28.546958. [PMID: 37425703 PMCID: PMC10327129 DOI: 10.1101/2023.06.28.546958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The DNAJ-PKAc fusion kinase is a defining feature of the adolescent liver cancer fibrolamellar carcinoma (FLC). A single lesion on chromosome 19 generates this mutant kinase by creating a fused gene encoding the chaperonin binding domain of Hsp40 (DNAJ) in frame with the catalytic core of protein kinase A (PKAc). FLC tumors are notoriously resistant to standard chemotherapies. Aberrant kinase activity is assumed to be a contributing factor. Yet recruitment of binding partners, such as the chaperone Hsp70, implies that the scaffolding function of DNAJ- PKAc may also underlie pathogenesis. By combining proximity proteomics with biochemical analyses and photoactivation live-cell imaging we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates. One validated DNAJ-PKAc target is the Bcl-2 associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Immunoblot and immunohistochemical analyses of FLC patient samples correlate increased levels of BAG2 with advanced disease and metastatic recurrences. BAG2 is linked to Bcl-2, an anti-apoptotic factor that delays cell death. Pharmacological approaches tested if the DNAJ- PKAc/Hsp70/BAG2 axis contributes to chemotherapeutic resistance in AML12 DNAJ-PKAc hepatocyte cell lines using the DNA damaging agent etoposide and the Bcl-2 inhibitor navitoclax. Wildtype AML12 cells were susceptible to each drug alone and in combination. In contrast, AML12 DNAJ-PKAc cells were moderately affected by etoposide, resistant to navitoclax, but markedly susceptible to the drug combination. These studies implicate BAG2 as a biomarker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.
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Collins KB, Scott JD. Phosphorylation, compartmentalization, and cardiac function. IUBMB Life 2023; 75:353-369. [PMID: 36177749 PMCID: PMC10049969 DOI: 10.1002/iub.2677] [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: 07/13/2022] [Accepted: 09/15/2022] [Indexed: 11/08/2022]
Abstract
Protein phosphorylation is a fundamental element of cell signaling. First discovered as a biochemical switch in glycogen metabolism, we now know that this posttranslational modification permeates all aspects of cellular behavior. In humans, over 540 protein kinases attach phosphate to acceptor amino acids, whereas around 160 phosphoprotein phosphatases remove phosphate to terminate signaling. Aberrant phosphorylation underlies disease, and kinase inhibitor drugs are increasingly used clinically as targeted therapies. Specificity in protein phosphorylation is achieved in part because kinases and phosphatases are spatially organized inside cells. A prototypic example is compartmentalization of the cyclic adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase A through association with A-kinase anchoring proteins. This configuration creates autonomous signaling islands where the anchored kinase is constrained in proximity to activators, effectors, and selected substates. This article primarily focuses on A kinase anchoring protein (AKAP) signaling in the heart with an emphasis on anchoring proteins that spatiotemporally coordinate excitation-contraction coupling and hypertrophic responses.
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Affiliation(s)
- Kerrie B. Collins
- Department of Pharmacology, University of Washington, School of Medicine, 1959 NE Pacific Ave, Seattle WA, 98195
| | - John D. Scott
- Department of Pharmacology, University of Washington, School of Medicine, 1959 NE Pacific Ave, Seattle WA, 98195
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Omar MH, Lauer SM, Lau HT, Golkowski M, Ong SE, Scott JD. Proximity biotinylation to define the local environment of the protein kinase A catalytic subunit in adrenal cells. STAR Protoc 2023; 4:101992. [PMID: 36607814 PMCID: PMC9826815 DOI: 10.1016/j.xpro.2022.101992] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/15/2022] [Accepted: 12/14/2022] [Indexed: 01/06/2023] Open
Abstract
Mutant protein kinase A catalytic subunit (PKAc) drives adrenal Cushing's syndrome, though its signaling interactions remain unclear. This protocol details steps to use live-cell proximity labeling to identify subcellular compartments and proteins closely associated with variants of PKAc in human adrenal cells. We include instructions for clonal cell line generation, live biotin labeling of proximal proteins, isolation of biotinylated proteins, and sample processing for proteomic analysis using the biotin ligase miniTurbo with wild-type and mutant PKAc.1,2 For complete details on the use and execution of this protocol, please refer to Omar et al. (2022).3.
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Affiliation(s)
- Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
| | - Sophia M Lauer
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Ho-Tak Lau
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Umoja Biopharma, Seattle, WA 98102, USA
| | - Martin Golkowski
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
| | - Shao-En Ong
- 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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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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Zhang R, Liu L, Wang F, Zhao W, Liu K, Yu H, Zhao S, Xu B, Zhang X, Chai J, Hao J. AKAP8L enhances the stemness and chemoresistance of gastric cancer cells by stabilizing SCD1 mRNA. Cell Death Dis 2022; 13:1041. [PMID: 36522343 PMCID: PMC9755141 DOI: 10.1038/s41419-022-05502-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/26/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022]
Abstract
Gastric cancer (GC) remains the third leading cause of cancer-related deaths. Chemoresistance is the major determinant of GC treatment failure. To explore the molecular mechanisms of GC chemoresistance, mass spectrometry was performed to detect the genes altered in expression between chemoresistant and chemosensitive GC. PRKA kinase anchor protein 8L (AKAP-8L) was identified as one of the top upregulated genes in chemoresistant GC tissues. Moreover, the higher AKAP-8L expression was associated with the lower survival rate in GC patients. Overexpression of AKAP-8L enhanced the GC cell stemness and chemoresistance of oxaliplatin in vivo and in vitro. AKAP-8L deficiency obtained the opposite results. Mechanistically, AKAP-8L interacted with Stearoyl-CoA desaturase 1 (SCD1) mRNA and IGF2BP1 protein, and regulated SCD1 mRNA stability via IGF2BP1-dependent manner. SCD1 played a critical role in mediating the function of AKAP-8L in GC cell stemness and chemoresistance. Clinically, AKAP-8L and SCD1 protein levels was positively associated with human GC chemoresistance. Taken together, our results demonstrated that AKAP-8L facilitates GC chemoresistance via regulating SCD1-mediated stemness of GC cells. AKAP8L may represent a novel therapeutic target to overcome GC chemoresistance.
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Affiliation(s)
- Ruihong Zhang
- grid.27255.370000 0004 1761 1174Key Laboratory of The Ministry of Education for Experimental Teratology, Department of Histology and Embryology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong P. R. China
| | - Luguang Liu
- grid.27255.370000 0004 1761 1174Department of Breast and Thyroid Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, 324 Jingwuweiqi Road, Jinan, Shandong P. R. China ,grid.410587.fDepartment of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, Shandong P. R. China
| | - Fengqin Wang
- grid.27255.370000 0004 1761 1174Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong P. R. China
| | - Weizhu Zhao
- grid.476866.dDepartment of Oncology, Binzhou People’s Hospital, 515 Huangheqi Road, Binzhou, Shandong P. R. China
| | - Kai Liu
- grid.410587.fDepartment of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, Shandong P. R. China
| | - Hang Yu
- grid.410587.fDepartment of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, Shandong P. R. China
| | - Siwei Zhao
- grid.410587.fDepartment of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, Shandong P. R. China
| | - Botao Xu
- grid.410587.fDepartment of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, Shandong P. R. China
| | - Xiaoli Zhang
- grid.27255.370000 0004 1761 1174Key Laboratory of The Ministry of Education for Experimental Teratology, Department of Histology and Embryology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong P. R. China
| | - Jie Chai
- grid.410587.fDepartment of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, Shandong P. R. China
| | - Jing Hao
- grid.27255.370000 0004 1761 1174Key Laboratory of The Ministry of Education for Experimental Teratology, Department of Histology and Embryology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong P. R. China
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Zhu F, Yuan C, Zhang X, Wang Z, Wang Q, Wang H. A-kinase anchoring protein 5-ancored calcineurin regulates the remodeling of H9c2 cardiomyocytes exposed to hypoxia and reoxygenation. Biomed Pharmacother 2022; 155:113689. [PMID: 36115111 DOI: 10.1016/j.biopha.2022.113689] [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: 07/17/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE A-kinase anchoring protein 5 (AKAP5) is involved in ventricular remodeling in rats with heart failure after myocardial infarction; however, the specific mechanism is not clear. This study investigated whether AKAP5 anchors calcineurin (CaN) to regulate the remodeling of H9c2 cardiomyocytes. METHODS H9c2 cells were subjected to hypoxia stress for 3 h and reoxygenation for 24 h to create a hypoxia-reoxygenation (H/R) model. These cells were divided into three groups: H/R (model), empty vector +H/R (NC), and siRNA-AKAP5+H/R (siRNA-AKAP5) groups. The non-H/R H9c2 cells were used as normal controls. Western blotting was used to detect cardiac hypertrophy-related protein expression in the cells, including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), beta myosin heavy chain (β-MHC), and phosphorylated nuclear factor of activated T-cell 3 (p-NFATc3). Phalloidin staining was used to label the cytoskeleton and the cell area in different groups was measured. Immunofluorescence staining and coimmunoprecipitation were used to study the relationship between AKAP5 and CaN. H9c2 cells pretreated with the CaN inhibitor FK506 were used to further verify the relationship between AKAP5 and CaN. RESULTS In the siRNA-AKAP5+H/R group, the expression level of cardiac hypertrophy-related proteins (ANP, BNP, and β-MHC) and CaN and the area of cardiomyocytes were significantly increased, while the p-NFATc3/NFATc3 ratio was decreased in H9c2H/R cells. AKAP5 and CaN proteins were colocalized and interacted in the cells. The CaN inhibitor significantly suppressed the expression of CaN, increased the p-NFATc3/NFATc3 ratio, and reduced the expression levels of ANP, BNP, and β-MHC proteins in the cells with low AKAP5 expression. CONCLUSIONS AKAP5 downregulation aggravated the remodeling of cardiomyocytes after H/R. AKAP5 may anchor CaN to form a complex, which in turn activates NFATc3 dephosphorylation and expression of hypertrophy-related proteins.
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Affiliation(s)
- Feng Zhu
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Chi Yuan
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Xu Zhang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China; Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institution, Wannan Medical College, Wuhu, China
| | - Zhi Wang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Qiushu Wang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China; Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institution, Wannan Medical College, Wuhu, China
| | - Hegui Wang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China.
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Svec KV, Howe AK. Protein Kinase A in cellular migration—Niche signaling of a ubiquitous kinase. Front Mol Biosci 2022; 9:953093. [PMID: 35959460 PMCID: PMC9361040 DOI: 10.3389/fmolb.2022.953093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 12/28/2022] Open
Abstract
Cell migration requires establishment and maintenance of directional polarity, which in turn requires spatial heterogeneity in the regulation of protrusion, retraction, and adhesion. Thus, the signaling proteins that regulate these various structural processes must also be distinctly regulated in subcellular space. Protein Kinase A (PKA) is a ubiquitous serine/threonine kinase involved in innumerable cellular processes. In the context of cell migration, it has a paradoxical role in that global inhibition or activation of PKA inhibits migration. It follows, then, that the subcellular regulation of PKA is key to bringing its proper permissive and restrictive functions to the correct parts of the cell. Proper subcellular regulation of PKA controls not only when and where it is active but also specifies the targets for that activity, allowing the cell to use a single, promiscuous kinase to exert distinct functions within different subcellular niches to facilitate cell movement. In this way, understanding PKA signaling in migration is a study in context and in the elegant coordination of distinct functions of a single protein in a complex cellular process.
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Affiliation(s)
- Kathryn V. Svec
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
| | - Alan K. Howe
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, V T, United States
- University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
- *Correspondence: Alan K. Howe,
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12
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Mitochondrial a Kinase Anchor Proteins in Cardiovascular Health and Disease: A Review Article on Behalf of the Working Group on Cellular and Molecular Biology of the Heart of the Italian Society of Cardiology. Int J Mol Sci 2022; 23:ijms23147691. [PMID: 35887048 PMCID: PMC9322728 DOI: 10.3390/ijms23147691] [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: 06/10/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 12/10/2022] Open
Abstract
Second messenger cyclic adenosine monophosphate (cAMP) has been found to regulate multiple mitochondrial functions, including respiration, dynamics, reactive oxygen species production, cell survival and death through the activation of cAMP-dependent protein kinase A (PKA) and other effectors. Several members of the large family of A kinase anchor proteins (AKAPs) have been previously shown to locally amplify cAMP/PKA signaling to mitochondria, promoting the assembly of signalosomes, regulating multiple cardiac functions under both physiological and pathological conditions. In this review, we will discuss roles and regulation of major mitochondria-targeted AKAPs, along with opportunities and challenges to modulate their functions for translational purposes in the cardiovascular system.
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13
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Omar MH, Byrne DP, Jones KN, Lakey TM, Collins KB, Lee KS, Daly LA, Forbush KA, Lau HT, Golkowski M, McKnight GS, Breault DT, Lefrançois-Martinez AM, Martinez A, Eyers CE, Baird GS, Ong SE, Smith FD, Eyers PA, Scott JD. Mislocalization of protein kinase A drives pathology in Cushing's syndrome. Cell Rep 2022; 40:111073. [PMID: 35830806 PMCID: PMC9311266 DOI: 10.1016/j.celrep.2022.111073] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/20/2022] [Accepted: 06/17/2022] [Indexed: 01/15/2023] Open
Abstract
Mutations in the catalytic subunit of protein kinase A (PKAc) drive the stress hormone disorder adrenal Cushing's syndrome. We define mechanisms of action for the PKAc-L205R and W196R variants. Proximity proteomic techniques demonstrate that both Cushing's mutants are excluded from A kinase-anchoring protein (AKAP)-signaling islands, whereas live-cell photoactivation microscopy reveals that these kinase mutants indiscriminately diffuse throughout the cell. Only cAMP analog drugs that displace native PKAc from AKAPs enhance cortisol release. Rescue experiments that incorporate PKAc mutants into AKAP complexes abolish cortisol overproduction, indicating that kinase anchoring restores normal endocrine function. Analyses of adrenal-specific PKAc-W196R knockin mice and Cushing's syndrome patient tissue reveal defective signaling mechanisms of the disease. Surprisingly each Cushing's mutant engages a different mitogenic-signaling pathway, with upregulation of YAP/TAZ by PKAc-L205R and ERK kinase activation by PKAc-W196R. Thus, aberrant spatiotemporal regulation of each Cushing's variant promotes the transmission of distinct downstream pathogenic signals.
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Affiliation(s)
- Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
| | - Dominic P Byrne
- Department of Biochemistry & Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Kiana N Jones
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Tyler M Lakey
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Kerrie B Collins
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Kyung-Soon Lee
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Leonard A Daly
- Centre for Proteome Research, Department of Biochemistry and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Katherine A Forbush
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Ho-Tak Lau
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Martin Golkowski
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - G Stanley McKnight
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - David T Breault
- Division of Endocrinology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Anne-Marie Lefrançois-Martinez
- Génétique, Reproduction et Développement (GReD), CNRS, INSERM, Université Clermont Auvergne, 63001 Clermont-Ferrand, France
| | - Antoine Martinez
- Génétique, Reproduction et Développement (GReD), CNRS, INSERM, Université Clermont Auvergne, 63001 Clermont-Ferrand, France
| | - Claire E Eyers
- Centre for Proteome Research, Department of Biochemistry and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Geoffrey S Baird
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Shao-En Ong
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - F Donelson Smith
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Patrick A Eyers
- Department of Biochemistry & Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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14
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Abstract
Many kinases use reversible docking interactions to augment the specificity of their catalytic domains. Such docking interactions are often structurally independent of the catalytic domain, which allow for a flexible combination of modules in evolution and in bioengineering. The affinity of docking interactions spans several orders of magnitude. This led us to ask how the affinity of the docking interaction affects enzymatic activity and how to pick the optimal interaction module to complement a given substrate. Here, we develop equations that predict the optimal binding strength of a kinase docking interaction and validate it using numerical simulations and steady-state phosphorylation kinetics for tethered protein kinase A. We show that a kinase-substrate pair has an optimum docking strength that depends on their enzymatic constants, the tether architecture, the substrate concentration, and the kinetics of the docking interactions. We show that a reversible tether enhances phosphorylation rates most when 1) the docking strength is intermediate, 2) the substrate is nonoptimal, 3) the substrate concentration is low, 4) the docking interaction has rapid exchange kinetics, and 5) the tether optimizes the effective concentration of the intramolecular reaction. This work serves as a framework for interpreting mutations in kinase docking interactions and as a design guide for engineering enzyme scaffolds.
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15
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Dynamic Regulation of Cysteine Oxidation and Phosphorylation in Myocardial Ischemia-Reperfusion Injury. Cells 2021; 10:cells10092388. [PMID: 34572037 PMCID: PMC8469016 DOI: 10.3390/cells10092388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 02/02/2023] Open
Abstract
Myocardial ischemia-reperfusion (I/R) injury significantly alters heart function following infarct and increases the risk of heart failure. Many studies have sought to preserve irreplaceable myocardium, termed cardioprotection, but few, if any, treatments have yielded a substantial reduction in clinical I/R injury. More research is needed to fully understand the molecular pathways that govern cardioprotection. Redox mechanisms, specifically cysteine oxidations, are acute and key regulators of molecular signaling cascades mediated by kinases. Here, we review the role of reactive oxygen species in modifying cysteine residues and how these modifications affect kinase function to impact cardioprotection. This exciting area of research may provide novel insight into mechanisms and likely lead to new treatments for I/R injury.
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16
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Gopalan J, Omar MH, Roy A, Cruz NM, Falcone J, Jones KN, Forbush KA, Himmelfarb J, Freedman BS, Scott JD. Targeting an anchored phosphatase-deacetylase unit restores renal ciliary homeostasis. eLife 2021; 10:e67828. [PMID: 34250905 PMCID: PMC8291974 DOI: 10.7554/elife.67828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/11/2021] [Indexed: 11/13/2022] Open
Abstract
Pathophysiological defects in water homeostasis can lead to renal failure. Likewise, common genetic disorders associated with abnormal cytoskeletal dynamics in the kidney collecting ducts and perturbed calcium and cAMP signaling in the ciliary compartment contribute to chronic kidney failure. We show that collecting ducts in mice lacking the A-Kinase anchoring protein AKAP220 exhibit enhanced development of primary cilia. Mechanistic studies reveal that AKAP220-associated protein phosphatase 1 (PP1) mediates this phenotype by promoting changes in the stability of histone deacetylase 6 (HDAC6) with concomitant defects in actin dynamics. This proceeds through a previously unrecognized adaptor function for PP1 as all ciliogenesis and cytoskeletal phenotypes are recapitulated in mIMCD3 knock-in cells expressing a phosphatase-targeting defective AKAP220-ΔPP1 mutant. Pharmacological blocking of local HDAC6 activity alters cilia development and reduces cystogenesis in kidney-on-chip and organoid models. These findings identify the AKAP220-PPI-HDAC6 pathway as a key effector in primary cilia development.
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Affiliation(s)
- Janani Gopalan
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Mitchell H Omar
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Ankita Roy
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - Nelly M Cruz
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - Jerome Falcone
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Kiana N Jones
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | | | - Jonathan Himmelfarb
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
| | - Benjamin S Freedman
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - John D Scott
- Department of Pharmacology, University of WashingtonSeattleUnited States
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17
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Kerbler SM, Natale R, Fernie AR, Zhang Y. From Affinity to Proximity Techniques to Investigate Protein Complexes in Plants. Int J Mol Sci 2021; 22:ijms22137101. [PMID: 34281155 PMCID: PMC8267905 DOI: 10.3390/ijms22137101] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/22/2021] [Accepted: 06/28/2021] [Indexed: 02/02/2023] Open
Abstract
The study of protein–protein interactions (PPIs) is fundamental in understanding the unique role of proteins within cells and their contribution to complex biological systems. While the toolkit to study PPIs has grown immensely in mammalian and unicellular eukaryote systems over recent years, application of these techniques in plants remains under-utilized. Affinity purification coupled to mass spectrometry (AP-MS) and proximity labeling coupled to mass spectrometry (PL-MS) are two powerful techniques that have significantly enhanced our understanding of PPIs. Relying on the specific binding properties of a protein to an immobilized ligand, AP is a fast, sensitive and targeted approach used to detect interactions between bait (protein of interest) and prey (interacting partners) under near-physiological conditions. Similarly, PL, which utilizes the close proximity of proteins to identify potential interacting partners, has the ability to detect transient or hydrophobic interactions under native conditions. Combined, these techniques have the potential to reveal an unprecedented spatial and temporal protein interaction network that better understands biological processes relevant to many fields of interest. In this review, we summarize the advantages and disadvantages of two increasingly common PPI determination techniques: AP-MS and PL-MS and discuss their important application to plant systems.
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Affiliation(s)
- Sandra M. Kerbler
- Theodor-Echtermeyer-Weg 1, Leibniz-Institut für Gemüse- und Zierpflanzenbau, 14979 Groβbeeren, Germany;
| | - Roberto Natale
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (R.N.); (A.R.F.)
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
| | - Alisdair R. Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (R.N.); (A.R.F.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Youjun Zhang
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (R.N.); (A.R.F.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Correspondence:
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18
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Kinase-anchoring proteins in ciliary signal transduction. Biochem J 2021; 478:1617-1629. [PMID: 33909027 DOI: 10.1042/bcj20200869] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 12/16/2022]
Abstract
Historically, the diffusion of chemical signals through the cell was thought to occur within a cytoplasmic soup bounded by the plasma membrane. This theory was predicated on the notion that all regulatory enzymes are soluble and moved with a Brownian motion. Although enzyme compartmentalization was initially rebuffed by biochemists as a 'last refuge of a scoundrel', signal relay through macromolecular complexes is now accepted as a fundamental tenet of the burgeoning field of spatial biology. A-Kinase anchoring proteins (AKAPs) are prototypic enzyme-organizing elements that position clusters of regulatory proteins at defined subcellular locations. In parallel, the primary cilium has gained recognition as a subcellular mechanosensory organelle that amplifies second messenger signals pertaining to metazoan development. This article highlights advances in our understanding of AKAP signaling within the primary cilium and how defective ciliary function contributes to an increasing number of diseases known as ciliopathies.
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19
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Yang X, Wen Z, Zhang D, Li Z, Li D, Nagalakshmi U, Dinesh-Kumar SP, Zhang Y. Proximity labeling: an emerging tool for probing in planta molecular interactions. PLANT COMMUNICATIONS 2021; 2:100137. [PMID: 33898976 PMCID: PMC8060727 DOI: 10.1016/j.xplc.2020.100137] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/30/2020] [Accepted: 12/14/2020] [Indexed: 05/13/2023]
Abstract
Protein-protein interaction (PPI) networks are key to nearly all aspects of cellular activity. Therefore, the identification of PPIs is important for understanding a specific biological process in an organism. Compared with conventional methods for probing PPIs, the recently described proximity labeling (PL) approach combined with mass spectrometry (MS)-based quantitative proteomics has emerged as a powerful approach for characterizing PPIs. However, the application of PL in planta remains in its infancy. Here, we summarize recent progress in PL and its potential utilization in plant biology. We specifically summarize advances in PL, including the development and comparison of different PL enzymes and the application of PL for deciphering various molecular interactions in different organisms with an emphasis on plant systems.
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Affiliation(s)
- Xinxin Yang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, P. R. China
| | - Zhiyan Wen
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, P. R. China
| | - Dingliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, P. R. China
| | - Zhen Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, P. R. China
| | - Ugrappa Nagalakshmi
- Department of Plant Biology and the Genome Center, College of Biological Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Savithramma P Dinesh-Kumar
- Department of Plant Biology and the Genome Center, College of Biological Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, P. R. China
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20
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Abstract
The field of cAMP signaling is witnessing exciting developments with the recognition that cAMP is compartmentalized and that spatial regulation of cAMP is critical for faithful signal coding. This realization has changed our understanding of cAMP signaling from a model in which cAMP connects a receptor at the plasma membrane to an intracellular effector in a linear pathway to a model in which cAMP signals propagate within a complex network of alternative branches and the specific functional outcome strictly depends on local regulation of cAMP levels and on selective activation of a limited number of branches within the network. In this review, we cover some of the early studies and summarize more recent evidence supporting the model of compartmentalized cAMP signaling, and we discuss how this knowledge is starting to provide original mechanistic insight into cell physiology and a novel framework for the identification of disease mechanisms that potentially opens new avenues for therapeutic interventions.
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Affiliation(s)
- Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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21
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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: 66] [Impact Index Per Article: 16.5] [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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22
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Bucko PJ, Garcia I, Manocha R, Bhat A, Wordeman L, Scott JD. Gravin-associated kinase signaling networks coordinate γ-tubulin organization at mitotic spindle poles. J Biol Chem 2020; 295:13784-13797. [PMID: 32732289 PMCID: PMC7535905 DOI: 10.1074/jbc.ra120.014791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/21/2020] [Indexed: 01/16/2023] Open
Abstract
Mitogenic signals that regulate cell division often proceed through multienzyme assemblies within defined intracellular compartments. The anchoring protein Gravin restricts the action of mitotic kinases and cell-cycle effectors to defined mitotic structures. In this report we discover that genetic deletion of Gravin disrupts proper accumulation and asymmetric distribution of γ-tubulin during mitosis. We utilize a new precision pharmacology tool, Local Kinase Inhibition, to inhibit the Gravin binding partner polo-like kinase 1 at spindle poles. Using a combination of gene-editing approaches, quantitative imaging, and biochemical assays, we provide evidence that disruption of local polo-like kinase 1 signaling underlies the γ-tubulin distribution defects observed with Gravin loss. Our study uncovers a new role for Gravin in coordinating γ-tubulin recruitment during mitosis and illuminates the mechanism by which signaling enzymes regulate this process at a distinct subcellular location.
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Affiliation(s)
- Paula J Bucko
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Irvin Garcia
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Ridhima Manocha
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Akansha Bhat
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Linda Wordeman
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, Washington, USA.
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23
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Bosch JA, Chen CL, Perrimon N. Proximity-dependent labeling methods for proteomic profiling in living cells: An update. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 10:e392. [PMID: 32909689 DOI: 10.1002/wdev.392] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/11/2020] [Accepted: 07/01/2020] [Indexed: 12/14/2022]
Abstract
Characterizing the proteome composition of organelles and subcellular regions of living cells can facilitate the understanding of cellular organization as well as protein interactome networks. Proximity labeling-based methods coupled with mass spectrometry (MS) offer a high-throughput approach for systematic analysis of spatially restricted proteomes. Proximity labeling utilizes enzymes that generate reactive radicals to covalently tag neighboring proteins. The tagged endogenous proteins can then be isolated for further analysis by MS. To analyze protein-protein interactions or identify components that localize to discrete subcellular compartments, spatial expression is achieved by fusing the enzyme to specific proteins or signal peptides that target to particular subcellular regions. Although these technologies have only been introduced recently, they have already provided deep insights into a wide range of biological processes. Here, we provide an updated description and comparison of proximity labeling methods, as well as their applications and improvements. As each method has its own unique features, the goal of this review is to describe how different proximity labeling methods can be used to answer different biological questions. This article is categorized under: Technologies > Analysis of Proteins.
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Affiliation(s)
- Justin A Bosch
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Chiao-Lin Chen
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Boston, Massachusetts, USA
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24
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Gabrovsek L, Collins KB, Aggarwal S, Saunders LM, Lau HT, Suh D, Sancak Y, Trapnell C, Ong SE, Smith FD, Scott JD. A-kinase-anchoring protein 1 (dAKAP1)-based signaling complexes coordinate local protein synthesis at the mitochondrial surface. J Biol Chem 2020; 295:10749-10765. [PMID: 32482893 PMCID: PMC7397098 DOI: 10.1074/jbc.ra120.013454] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/20/2020] [Indexed: 12/30/2022] Open
Abstract
Compartmentalization of macromolecules is a ubiquitous molecular mechanism that drives numerous cellular functions. The appropriate organization of enzymes in space and time enables the precise transmission and integration of intracellular signals. Molecular scaffolds constrain signaling enzymes to influence the regional modulation of these physiological processes. Mitochondrial targeting of protein kinases and protein phosphatases provides a means to locally control the phosphorylation status and action of proteins on the surface of this organelle. Dual-specificity protein kinase A anchoring protein 1 (dAKAP1) is a multivalent binding protein that targets protein kinase A (PKA), RNAs, and other signaling enzymes to the outer mitochondrial membrane. Many AKAPs recruit a diverse set of binding partners that coordinate a broad range of cellular processes. Here, results of MS and biochemical analyses reveal that dAKAP1 anchors additional components, including the ribonucleoprotein granule components La-related protein 4 (LARP4) and polyadenylate-binding protein 1 (PABPC1). Local translation of mRNAs at organelles is a means to spatially control the synthesis of proteins. RNA-Seq data demonstrate that dAKAP1 binds mRNAs encoding proteins required for mitochondrial metabolism, including succinate dehydrogenase. Functional studies suggest that the loss of dAKAP1-RNA interactions reduces mitochondrial electron transport chain activity. Hence, dAKAP1 plays a previously unappreciated role as a molecular interface between second messenger signaling and local protein synthesis machinery.
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Affiliation(s)
- Laura Gabrovsek
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
- Program in Molecular and Cellular Biology, University of Washington, Seattle, Washington, USA
| | - Kerrie B Collins
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Stacey Aggarwal
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Lauren M Saunders
- Program in Molecular and Cellular Biology, University of Washington, Seattle, Washington, USA
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Ho-Tak Lau
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Danny Suh
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Yasemin Sancak
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Cole Trapnell
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Shao-En Ong
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - F Donelson Smith
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
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25
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Bucko PJ, Scott JD. Drugs That Regulate Local Cell Signaling: AKAP Targeting as a Therapeutic Option. Annu Rev Pharmacol Toxicol 2020; 61:361-379. [PMID: 32628872 DOI: 10.1146/annurev-pharmtox-022420-112134] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells respond to environmental cues by mobilizing signal transduction cascades that engage protein kinases and phosphoprotein phosphatases. Correct organization of these enzymes in space and time enables the efficient and precise transmission of chemical signals. The cyclic AMP-dependent protein kinase A is compartmentalized through its association with A-kinase anchoring proteins (AKAPs). AKAPs are a family of multivalent scaffolds that constrain signaling enzymes and effectors at subcellular locations to drive essential physiological events. More recently, it has been recognized that defective signaling in certain endocrine disorders and cancers proceeds through pathological AKAP complexes. Consequently, pharmacologically targeting these macromolecular complexes unlocks new therapeutic opportunities for a growing number of clinical indications. This review highlights recent findings on AKAP signaling in disease, particularly in certain cancers, and offers an overview of peptides and small molecules that locally regulate AKAP-binding partners.
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Affiliation(s)
- Paula J Bucko
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA; ,
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA; ,
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26
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AKAP5 anchors PKA to enhance regulation of the HERG channel. Int J Biochem Cell Biol 2020; 122:105741. [PMID: 32173522 DOI: 10.1016/j.biocel.2020.105741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/24/2020] [Accepted: 03/11/2020] [Indexed: 11/21/2022]
Abstract
The activation of the β-adrenergic receptor (β-AR) regulates the human ether a-go-go-related gene (HERG) channel via protein kinase A (PKA), which in turn induces lethal arrhythmia in patients with long QT syndromes (LQTS). However, the role of A-kinase anchoring proteins (AKAPs) in PKA's regulation of the HERG channel and its molecular mechanism are not clear. Here, HEK293 cells were transfected with the HERG gene alone or co-transfected with HERG and AKAP5 using Lipofectamine 2000. Western blotting was performed to determine HERG protein expression, and immunofluorescence and immunoprecipitation were used to assess the binding and cellular colocalization of HERG, AKAP5, and PKA. The HEK293-HERG and HEK293-HERG + AKAP5 cells were treated with forskolin at different concentrations and different time. HERG protein expression significantly increased under all treatment conditions (P < 0.001). The level of HERG protein expression in HEK293-HERG + AKAP5 cells was higher than that observed in HEK293-HERG cells (P < 0.001). Immunofluorescence and immunoprecipitation indicated that HERG bound to PKA and AKAP5 and was colocalized at the cell membrane. The HERG channel protein, AKAP5, and PKA interacted with each other and appeared to form intracellular complexes. These results provide evidence for a novel mechanism which AKAP5 anchors PKA to up-regulate the HERG channel protein.
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27
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Schleicher K, Zaccolo M. Axelrod Symposium 2019: Phosphoproteomic Analysis of G-Protein-Coupled Pathways. Mol Pharmacol 2020; 99:383-391. [PMID: 32111700 DOI: 10.1124/mol.119.118869] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/10/2020] [Indexed: 12/13/2022] Open
Abstract
By limiting unrestricted activation of intracellular effectors, compartmentalized signaling of cyclic nucleotides confers specificity to extracellular stimuli and is critical for the development and health of cells and organisms. Dissecting the molecular mechanisms that allow local control of cyclic nucleotide signaling is essential for our understanding of physiology and pathophysiology, but mapping the dynamics and regulation of compartmentalized signaling is a challenge. In this minireview we summarize advanced imaging and proteomics techniques that have been successfully used to probe compartmentalized cAMP signaling in eukaryotic cells. Subcellularly targeted fluorescence resonance energy transfer sensors can precisely locate and measure compartmentalized cAMP, and this allows us to estimate the range of effector activation. Because cAMP effector proteins often cluster together with their targets and cAMP regulatory proteins to form discrete cAMP signalosomes, proteomics and phosphoproteomics analysis have more recently been used to identify additional players in the cAMP-signaling cascade. We propose that the synergistic use of the techniques discussed could prove fruitful in generating a detailed map of cAMP signalosomes and reveal new details of compartmentalized signaling. Compiling a dynamic map of cAMP nanodomains in defined cell types would establish a blueprint for better understanding the alteration of signaling compartments associated with disease and would provide a molecular basis for targeted therapeutic strategies. SIGNIFICANCE STATEMENT: cAMP signaling is compartmentalized. Some functionally important cellular signaling compartments operate on a nanometer scale, and their integrity is essential to maintain cellular function and appropriate responses to extracellular stimuli. Compartmentalized signaling provides an opportunity for precision medicine interventions. Our detailed understanding of the composition, function, and regulation of cAMP-signaling nanodomains in health and disease is essential and will benefit from harnessing the right combination of advanced biochemical and imaging techniques.
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Affiliation(s)
- Katharina Schleicher
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Hu X, Harvey SE, Zheng R, Lyu J, Grzeskowiak CL, Powell E, Piwnica-Worms H, Scott KL, Cheng C. The RNA-binding protein AKAP8 suppresses tumor metastasis by antagonizing EMT-associated alternative splicing. Nat Commun 2020; 11:486. [PMID: 31980632 PMCID: PMC6981122 DOI: 10.1038/s41467-020-14304-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 12/17/2019] [Indexed: 01/01/2023] Open
Abstract
Alternative splicing has been shown to causally contribute to the epithelial–mesenchymal transition (EMT) and tumor metastasis. However, the scope of splicing factors that govern alternative splicing in these processes remains largely unexplored. Here we report the identification of A-Kinase Anchor Protein (AKAP8) as a splicing regulatory factor that impedes EMT and breast cancer metastasis. AKAP8 not only is capable of inhibiting splicing activity of the EMT-promoting splicing regulator hnRNPM through protein–protein interaction, it also directly binds to RNA and alters splicing outcomes. Genome-wide analysis shows that AKAP8 promotes an epithelial cell state splicing program. Experimental manipulation of an AKAP8 splicing target CLSTN1 revealed that splice isoform switching of CLSTN1 is crucial for EMT. Moreover, AKAP8 expression and the alternative splicing of CLSTN1 predict breast cancer patient survival. Together, our work demonstrates the essentiality of RNA metabolism that impinges on metastatic breast cancer. Splice isoform switching regulated by the heterogeneous nuclear ribonucleoprotein M (hnRNPM) induces EMT and metastasis. Here, the authors report that AKAP8 is a metastasis suppressor that inhibits the splicing activity of hnRNPM and antagonizes genome-wide EMT-associated alternative splicing to maintain epithelial cell state.
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Affiliation(s)
- Xiaohui Hu
- Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Samuel E Harvey
- Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Rong Zheng
- Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jingyi Lyu
- Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Caitlin L Grzeskowiak
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Emily Powell
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Helen Piwnica-Worms
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Kenneth L Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Chonghui Cheng
- Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
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29
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The Role of the Popeye Domain Containing Gene Family in Organ Homeostasis. Cells 2019; 8:cells8121594. [PMID: 31817925 PMCID: PMC6952887 DOI: 10.3390/cells8121594] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 01/01/2023] Open
Abstract
The Popeye domain containing (POPDC) gene family consists of POPDC1 (also known as BVES), POPDC2 and POPDC3 and encodes a novel class of cyclic adenosine monophosphate (cAMP) effector proteins. Despite first reports of their isolation and initial characterization at the protein level dating back 20 years, only recently major advances in defining their biological functions and disease association have been made. Loss-of-function experiments in mice and zebrafish established an important role in skeletal muscle regeneration, heart rhythm control and stress signaling. Patients suffering from muscular dystrophy and atrioventricular block were found to carry missense and nonsense mutations in either of the three POPDC genes, which suggests an important function in the control of striated muscle homeostasis. However, POPDC genes are also expressed in a number of epithelial cells and function as tumor suppressor genes involved in the control of epithelial structure, tight junction formation and signaling. Suppression of POPDC genes enhances tumor cell proliferation, migration, invasion and metastasis in a variety of human cancers, thus promoting a malignant phenotype. Moreover, downregulation of POPDC1 and POPDC3 expression in different cancer types has been associated with poor prognosis. However, high POPDC3 expression has also been correlated to poor clinical prognosis in head and neck squamous cell carcinoma, suggesting that POPDC3 potentially plays different roles in the progression of different types of cancer. Interestingly, a gain of POPDC1 function in tumor cells inhibits cell proliferation, migration and invasion thereby reducing malignancy. Furthermore, POPDC proteins have been implicated in the control of cell cycle genes and epidermal growth factor and Wnt signaling. Work in tumor cell lines suggest that cyclic nucleotide binding may also be important in epithelial cells. Thus, POPDC proteins have a prominent role in tissue homeostasis and cellular signaling in both epithelia and striated muscle.
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30
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Verma NK, Chalasani MLS, Scott JD, Kelleher D. CG-NAP/Kinase Interactions Fine-Tune T Cell Functions. Front Immunol 2019; 10:2642. [PMID: 31781123 PMCID: PMC6861388 DOI: 10.3389/fimmu.2019.02642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/24/2019] [Indexed: 01/04/2023] Open
Abstract
CG-NAP, also known as AKAP450, is an anchoring/adaptor protein that streamlines signal transduction in various cell types by localizing signaling proteins and enzymes with their substrates. Great efforts are being devoted to elucidating functional roles of this protein and associated macromolecular signaling complex. Increasing understanding of pathways involved in regulating T lymphocytes suggests that CG-NAP can facilitate dynamic interactions between kinases and their substrates and thus fine-tune T cell motility and effector functions. As a result, new binding partners of CG-NAP are continually being uncovered. Here, we review recent advances in CG-NAP research, focusing on its interactions with kinases in T cells with an emphasis on the possible role of this anchoring protein as a target for therapeutic intervention in immune-mediated diseases.
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Affiliation(s)
- Navin Kumar Verma
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | | | - John D Scott
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA, United States
| | - Dermot Kelleher
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore.,Departments of Medicine and Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
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31
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Hakem Zadeh F, Teng ACT, Kuzmanov U, Chambers PJ, Tupling AR, Gramolini AO. AKAP6 and phospholamban colocalize and interact in HEK-293T cells and primary murine cardiomyocytes. Physiol Rep 2019; 7:e14144. [PMID: 31325238 PMCID: PMC6642276 DOI: 10.14814/phy2.14144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/16/2019] [Accepted: 05/24/2019] [Indexed: 12/21/2022] Open
Abstract
Phospholamban (PLN) is an important Ca2+ modulator at the sarcoplasmic reticulum (SR) of striated muscles. It physically interacts and inhibits sarcoplasmic reticulum Ca2+ATPase (SERCA2) function, whereas a protein kinase A (PKA)‐dependent phosphorylation at its serine 16 reverses the inhibition. The underlying mechanism of this post‐translational modification, however, remains not fully understood. Using publicly available databases, we identified A‐kinase anchoring protein 6 (AKAP6) as a candidate that might play some roles in PLN phosphorylation. Immunofluorescence showed colocalization between GFP‐AKAP6 and PLN in transfected HEK‐293T cells and cultured mouse neonatal cardiomyocytes (CMNCs). Co‐immunoprecipitation confirmed the functional interaction between AKAP6 and PLN in HEK‐293T and isolated adult rat cardiomyocytes in response to isoproterenol stimulation. Functionally, AKAP6 promoted Ca2+ uptake activity of SERCA1 in cotransfected HEK‐293T cells despite the presence of PLN. These results were further confirmed in adult rat cardiomyocytes. Immunofluorescence showed colocalization of both proteins around the perinuclear region, while protein–protein interaction was corroborated by immunoprecipitation of the nucleus‐enriched fraction of rat hearts. Our findings suggest AKAP6 as a novel interacting partner to PLN in HEK‐293T and murine cardiomyocytes.
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Affiliation(s)
- Farigol Hakem Zadeh
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario.,Translational Biology and Engineering Program (TBEP), Ted Rogers Centre for Heart Research, Toronto, Ontario
| | - Allen C T Teng
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario.,Translational Biology and Engineering Program (TBEP), Ted Rogers Centre for Heart Research, Toronto, Ontario
| | - Uros Kuzmanov
- Translational Biology and Engineering Program (TBEP), Ted Rogers Centre for Heart Research, Toronto, Ontario
| | - Paige J Chambers
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario
| | - Allan R Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario
| | - Anthony O Gramolini
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario.,Translational Biology and Engineering Program (TBEP), Ted Rogers Centre for Heart Research, Toronto, Ontario
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32
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Baltzer S, Klussmann E. Small molecules for modulating the localisation of the water channel aquaporin-2-disease relevance and perspectives for targeting local cAMP signalling. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1049-1064. [PMID: 31300862 DOI: 10.1007/s00210-019-01686-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/23/2022]
Abstract
The tight spatial and temporal organisation of cyclic adenosine monophosphate (cAMP) signalling plays a key role in arginine-vasopressin (AVP)-mediated water reabsorption in renal collecting duct principal cells and in a plethora of other processes such as in the control of cardiac myocyte contractility. This review critically discusses in vitro- and cell-based screening strategies for the identification of small molecules that interfere with AVP/cAMP signalling in renal principal cells; it features phenotypic screening and approaches for targeting protein-protein interactions of A-kinase anchoring proteins (AKAPs), which organise local cAMP signalling hubs. The discovery of novel chemical entities for the modulation of local cAMP will not only provide tools for elucidating molecular mechanisms underlying cAMP signalling. Novel chemical entities can also serve as starting points for the development of novel drugs for the treatment of human diseases. Examples illustrate how screening for small molecules can pave the way to novel approaches for the treatment of certain forms of diabetes insipidus, a disease caused by defects in AVP-mediated water reabsorption.
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Affiliation(s)
- Sandrine Baltzer
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany. .,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany. .,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health and Vegetative Physiology, Berlin, Germany.
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33
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Turnham RE, Smith FD, Kenerson HL, Omar MH, Golkowski M, Garcia I, Bauer R, Lau HT, Sullivan KM, Langeberg LK, Ong SE, Riehle KJ, Yeung RS, Scott JD. An acquired scaffolding function of the DNAJ-PKAc fusion contributes to oncogenic signaling in fibrolamellar carcinoma. eLife 2019; 8:44187. [PMID: 31063128 PMCID: PMC6533061 DOI: 10.7554/elife.44187] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 05/05/2019] [Indexed: 12/22/2022] Open
Abstract
Fibrolamellar carcinoma (FLC) is a rare liver cancer. FLCs uniquely produce DNAJ-PKAc, a chimeric enzyme consisting of a chaperonin-binding domain fused to the Cα subunit of protein kinase A. Biochemical analyses of clinical samples reveal that a unique property of this fusion enzyme is the ability to recruit heat shock protein 70 (Hsp70). This cellular chaperonin is frequently up-regulated in cancers. Gene-editing of mouse hepatocytes generated disease-relevant AML12DNAJ-PKAc cell lines. Further analyses indicate that the proto-oncogene A-kinase anchoring protein-Lbc is up-regulated in FLC and functions to cluster DNAJ-PKAc/Hsp70 sub-complexes with a RAF-MEK-ERK kinase module. Drug screening reveals Hsp70 and MEK inhibitor combinations that selectively block proliferation of AML12DNAJ-PKAc cells. Phosphoproteomic profiling demonstrates that DNAJ-PKAc biases the signaling landscape toward ERK activation and engages downstream kinase cascades. Thus, the oncogenic action of DNAJ-PKAc involves an acquired scaffolding function that permits recruitment of Hsp70 and mobilization of local ERK signaling. Fibrolamellar carcinoma (or FLC for short) is a rare type of liver cancer that affects teenagers and young adults. FLC tumors are often resistant to standard radiotherapy or chemotherapy treatments. The only way to treat FLC is to remove tumors by surgery. However, often the tumors come back after initial treatment and spread to other locations. Therefore, there is a genuine need to improve the treatment options available to FLC patients. The tumor cells of FLC patients contain a genetic defect that fuses together two genes, which produce proteins called DNAJ and PKAc. Normally, DNAJ helps other proteins in the cell to fold into their correct shapes, while PKAc is an enzyme that can control how cells communicate. However, it is not clear what the abnormal DNAJ-PKAc fusion protein does, or how it causes FLC. Turnham, Smith et al. have now used gene editing to make mouse liver cells that mimic the human FLC mutation. Biochemical experiments on these cells showed that the DNAJ-PKAc protein brings together unique combinations of enzymes that drive uncontrolled cell growth. Analyzing cells taken from tumors in FLC patients confirmed that these enzymes are also activated in the human disease. Turnham, Smith et al. also found that combinations of drugs that simultaneously target the DNAJ-PKAc protein and the recruited enzymes slowed down the growth of FLC cells. More experiments are now needed to test these drug combinations on human FLC cells or in mice.
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Affiliation(s)
- Rigney E Turnham
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - F Donelson Smith
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Heidi L Kenerson
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Mitchell H Omar
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Martin Golkowski
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Irvin Garcia
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Renay Bauer
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Ho-Tak Lau
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Kevin M Sullivan
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Lorene K Langeberg
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Shao-En Ong
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Kimberly J Riehle
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Raymond S Yeung
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - John D Scott
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
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34
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Lucero M, Suarez AE, Chambers JW. Phosphoregulation on mitochondria: Integration of cell and organelle responses. CNS Neurosci Ther 2019; 25:837-858. [PMID: 31025544 PMCID: PMC6566066 DOI: 10.1111/cns.13141] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 03/29/2019] [Accepted: 04/04/2019] [Indexed: 12/20/2022] Open
Abstract
Mitochondria are highly integrated organelles that are crucial to cell adaptation and mitigating adverse physiology. Recent studies demonstrate that fundamental signal transduction pathways incorporate mitochondrial substrates into their biological programs. Reversible phosphorylation is emerging as a useful mechanism to modulate mitochondrial function in accordance with cellular changes. Critical serine/threonine protein kinases, such as the c-Jun N-terminal kinase (JNK), protein kinase A (PKA), PTEN-induced kinase-1 (PINK1), and AMP-dependent protein kinase (AMPK), readily translocate to the outer mitochondrial membrane (OMM), the interface of mitochondria-cell communication. OMM protein kinases phosphorylate diverse mitochondrial substrates that have discrete effects on organelle dynamics, protein import, respiratory complex activity, antioxidant capacity, and apoptosis. OMM phosphorylation events can be tempered through the actions of local protein phosphatases, such as mitogen-activated protein kinase phosphatase-1 (MKP-1) and protein phosphatase 2A (PP2A), to regulate the extent and duration of signaling. The central mediators of OMM signal transduction are the scaffold proteins because the relative abundance of these accessory proteins determines the magnitude and duration of a signaling event on the mitochondrial surface, which dictates the biological outcome of a local signal transduction pathway. The concentrations of scaffold proteins, such as A-kinase anchoring proteins (AKAPs) and Sab (or SH3 binding protein 5-SH3BP5), have been shown to influence neuronal survival and vulnerability, respectively, in models of Parkinson's disease (PD), highlighting the importance of OMM signaling to health and disease. Despite recent progress, much remains to be discovered concerning the mechanisms of OMM signaling. Nonetheless, enhancing beneficial OMM signaling events and inhibiting detrimental protein-protein interactions on the mitochondrial surface may represent highly selective approaches to restore mitochondrial health and homeostasis and mitigate organelle dysfunction in conditions such as PD.
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Affiliation(s)
- Maribel Lucero
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, the Biomolecular Sciences Institute, Florida International University, Miami, Florida
| | - Ana E Suarez
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, the Biomolecular Sciences Institute, Florida International University, Miami, Florida
| | - Jeremy W Chambers
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, the Biomolecular Sciences Institute, Florida International University, Miami, Florida
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35
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Aggarwal S, Gabrovsek L, Langeberg LK, Golkowski M, Ong SE, Smith FD, Scott JD. Depletion of dAKAP1-protein kinase A signaling islands from the outer mitochondrial membrane alters breast cancer cell metabolism and motility. J Biol Chem 2018; 294:3152-3168. [PMID: 30598507 DOI: 10.1074/jbc.ra118.006741] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/21/2018] [Indexed: 01/23/2023] Open
Abstract
Breast cancer screening and new precision therapies have led to improved patient outcomes. Yet, a positive prognosis is less certain when primary tumors metastasize. Metastasis requires a coordinated program of cellular changes that promote increased survival, migration, and energy consumption. These pathways converge on mitochondrial function, where distinct signaling networks of kinases, phosphatases, and metabolic enzymes regulate these processes. The protein kinase A-anchoring protein dAKAP1 compartmentalizes protein kinase A (PKA) and other signaling enzymes at the outer mitochondrial membrane and thereby controls mitochondrial function and dynamics. Modulation of these processes occurs in part through regulation of dynamin-related protein 1 (Drp1). Here, we report an inverse relationship between the expression of dAKAP1 and mesenchymal markers in breast cancer. Molecular, cellular, and in silico analyses of breast cancer cell lines confirmed that dAKAP1 depletion is associated with impaired mitochondrial function and dynamics, as well as with increased glycolytic potential and invasiveness. Furthermore, disruption of dAKAP1-PKA complexes affected cell motility and mitochondrial movement toward the leading edge in invasive breast cancer cells. We therefore propose that depletion of dAKAP1-PKA "signaling islands" from the outer mitochondrial membrane augments progression toward metastatic breast cancer.
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Affiliation(s)
- Stacey Aggarwal
- From the Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195
| | - Laura Gabrovsek
- From the Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195
| | - Lorene K Langeberg
- From the Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195
| | - Martin Golkowski
- From the Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195
| | - Shao-En Ong
- From the Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195
| | - F Donelson Smith
- From the Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195
| | - John D Scott
- From the Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195
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