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Kang M, Senatore AJ, Naughton H, McTigue M, Beltman RJ, Herppich AA, Pflum MKH, Howe AK. Protein kinase A is a functional component of focal adhesions. J Biol Chem 2024; 300:107234. [PMID: 38552737 PMCID: PMC11044056 DOI: 10.1016/j.jbc.2024.107234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/06/2024] [Accepted: 03/17/2024] [Indexed: 04/09/2024] Open
Abstract
Focal adhesions (FAs) form the junction between extracellular matrix (ECM)-bound integrins and the actin cytoskeleton and also transmit signals that regulate cell adhesion, cytoskeletal dynamics, and cell migration. While many of these signals are rooted in reversible tyrosine phosphorylation, phosphorylation of FA proteins on Ser/Thr residues is far more abundant yet its mechanisms and consequences are far less understood. The cAMP-dependent protein kinase (protein kinase A; PKA) has important roles in cell adhesion and cell migration and is both an effector and regulator of integrin-mediated adhesion to the ECM. Importantly, subcellular localization plays a critically important role in specifying PKA function. Here, we show that PKA is present in isolated FA-cytoskeleton complexes and active within FAs in live cells. Furthermore, using kinase-catalyzed biotinylation of isolated FA-cytoskeleton complexes, we identify 53 high-stringency candidate PKA substrates within FAs. From this list, we validate tensin-3 (Tns3)-a well-established molecular scaffold, regulator of cell migration, and a component of focal and fibrillar adhesions-as a novel direct substrate for PKA. These observations identify a new pathway for phospho-regulation of Tns3 and, importantly, establish a new and important niche for localized PKA signaling and thus provide a foundation for further investigation of the role of PKA in the regulation of FA dynamics and signaling.
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Affiliation(s)
- Mingu Kang
- Department of Pharmacology, Larner College of Medicine, University of Vermont Cancer Center, Burlington, Vermont, USA; Department of Molecular Physiology & Biophysics, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Amanda J Senatore
- Department of Pharmacology, Larner College of Medicine, University of Vermont Cancer Center, Burlington, Vermont, USA; Department of Molecular Physiology & Biophysics, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Hannah Naughton
- Department of Pharmacology, Larner College of Medicine, University of Vermont Cancer Center, Burlington, Vermont, USA; Department of Molecular Physiology & Biophysics, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Madeline McTigue
- Department of Pharmacology, Larner College of Medicine, University of Vermont Cancer Center, Burlington, Vermont, USA; Department of Molecular Physiology & Biophysics, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Rachel J Beltman
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Andrew A Herppich
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Mary Kay H Pflum
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Alan K Howe
- Department of Pharmacology, Larner College of Medicine, University of Vermont Cancer Center, Burlington, Vermont, USA; Department of Molecular Physiology & Biophysics, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA.
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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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Kang M, Senatore AJ, Naughton H, McTigue M, Beltman RJ, Herppich AA, Pflum MKH, Howe AK. Protein Kinase A is a Functional Component of Focal Adhesions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.18.553932. [PMID: 37645771 PMCID: PMC10462105 DOI: 10.1101/2023.08.18.553932] [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
Focal adhesions (FAs) form the junction between extracellular matrix (ECM)-bound integrins and the actin cytoskeleton and also transmit signals that regulate cell adhesion, cytoskeletal dynamics, and cell migration. While many of these signals are rooted in reversible tyrosine phosphorylation, phosphorylation of FA proteins on Ser/Thr residues is far more abundant yet its mechanisms and consequences are far less understood. The cAMP-dependent protein kinase (protein kinase A; PKA) has important roles in cell adhesion and cell migration and is both an effector and regulator of integrin-mediated adhesion to the ECM. Importantly, subcellular localization plays a critically important role in specifying PKA function. Here, we show that PKA is present in isolated FA-cytoskeleton complexes and active within FAs in live cells. Furthermore, using kinase-catalyzed biotinylation of isolated FA-cytoskeleton complexes, we identify fifty-three high-stringency candidate PKA substrates within FAs. From this list, we validate tensin-3 (Tns3) - a well-established molecular scaffold, regulator of cell migration, and component of focal and fibrillar adhesions - as a novel direct substrate for PKA. These observations identify a new pathway for phospho-regulation of Tns3 and, importantly, establish a new and important niche for localized PKA signaling and thus provide a foundation for further investigation of the role of PKA in the regulation of FA dynamics and signaling.
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Asbjornsdottir B, Sigurdsson S, Miranda-Ribera A, Fiorentino M, Konno T, Lan J, Gudmundsson LS, Gottfredsson M, Lauth B, Birgisdottir BE, Fasano A. Evaluating Prophylactic Effect of Bovine Colostrum on Intestinal Barrier Function in Zonulin Transgenic Mice: A Transcriptomic Study. Int J Mol Sci 2023; 24:14730. [PMID: 37834178 PMCID: PMC10572565 DOI: 10.3390/ijms241914730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/22/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
The intestinal barrier comprises a single layer of epithelial cells tightly joined to form a physical barrier. Disruption or compromise of the intestinal barrier can lead to the inadvertent activation of immune cells, potentially causing an increased risk of chronic inflammation in various tissues. Recent research has suggested that specific dietary components may influence the function of the intestinal barrier, potentially offering a means to prevent or mitigate inflammatory disorders. However, the precise mechanism underlying these effects remains unclear. Bovine colostrum (BC), the first milk from cows after calving, is a natural source of nutrients with immunomodulatory, anti-inflammatory, and gut-barrier fortifying properties. This novel study sought to investigate the transcriptome in BC-treated Zonulin transgenic mice (Ztm), characterized by dysbiotic microbiota, intestinal hyperpermeability, and mild hyperactivity, applying RNA sequencing. Seventy-five tissue samples from the duodenum, colon, and brain of Ztm and wild-type (WT) mice were dissected, processed, and RNA sequenced. The expression profiles were analyzed and integrated to identify differentially expressed genes (DEGs) and differentially expressed transcripts (DETs). These were then further examined using bioinformatics tools. RNA-seq analysis identified 1298 DEGs and 20,952 DETs in the paired (Ztm treatment vs. Ztm control) and reference (WT controls) groups. Of these, 733 DEGs and 10,476 DETs were upregulated, while 565 DEGs and 6097 DETs were downregulated. BC-treated Ztm female mice showed significant upregulation of cingulin (Cgn) and claudin 12 (Cldn12) duodenum and protein interactions, as well as molecular pathways and interactions pertaining to tight junctions, while BC-treated Ztm males displayed an upregulation of transcripts like occludin (Ocln) and Rho/Rac guanine nucleotide exchange factor 2 (Arhgf2) and cellular structures and interfaces, protein-protein interactions, and organization and response mechanisms. This comprehensive analysis reveals the influence of BC treatment on tight junctions (TJs) and Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) signaling pathway gene expressions. The present study is the first to analyze intestinal and brain samples from BC-treated Ztm mice applying high-throughput RNA sequencing. This study revealed molecular interaction in intestinal barrier function and identified hub genes and their functional pathways and biological processes in response to BC treatment in Ztm mice. Further research is needed to validate these findings and explore their implications for dietary interventions aimed at improving intestinal barrier integrity and function. The MGH Institutional Animal Care and Use Committee authorized the animal study (2013N000013).
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Affiliation(s)
- Birna Asbjornsdottir
- Department of Pediatric Gastroenterology and Nutrition, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; (B.A.); (M.F.); (T.K.); (J.L.)
- School of Health Sciences, Faculty of Medicine, University of Iceland, 102 Reykjavik, Iceland (M.G.)
- Unit for Nutrition Research, Landspitali University Hospital, Faculty of Food Science and Nutrition, University of Iceland, 102 Reykjavik, Iceland
| | - Snaevar Sigurdsson
- School of Health Sciences, Faculty of Medicine, University of Iceland, 102 Reykjavik, Iceland (M.G.)
- Biomedical Center, University of Iceland, 102 Reykjavik, Iceland
| | - Alba Miranda-Ribera
- Department of Pediatric Gastroenterology and Nutrition, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; (B.A.); (M.F.); (T.K.); (J.L.)
| | - Maria Fiorentino
- Department of Pediatric Gastroenterology and Nutrition, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; (B.A.); (M.F.); (T.K.); (J.L.)
| | - Takumi Konno
- Department of Pediatric Gastroenterology and Nutrition, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; (B.A.); (M.F.); (T.K.); (J.L.)
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Jinggang Lan
- Department of Pediatric Gastroenterology and Nutrition, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; (B.A.); (M.F.); (T.K.); (J.L.)
| | - Larus S. Gudmundsson
- School of Health Sciences, Faculty of Pharmaceutical Sciences, University of Iceland, 102 Reykjavik, Iceland
| | - Magnus Gottfredsson
- School of Health Sciences, Faculty of Medicine, University of Iceland, 102 Reykjavik, Iceland (M.G.)
- Department of Scientific Affairs, Landspitali University Hospital, 102 Reykjavik, Iceland
- Department of Infectious Diseases, Landspitali University Hospital, 102 Reykjavik, Iceland
| | - Bertrand Lauth
- School of Health Sciences, Faculty of Medicine, University of Iceland, 102 Reykjavik, Iceland (M.G.)
- Department of Child and Adolescent Psychiatry, Landspitali University Hospital, 102 Reykjavik, Iceland
| | - Bryndis Eva Birgisdottir
- Unit for Nutrition Research, Landspitali University Hospital, Faculty of Food Science and Nutrition, University of Iceland, 102 Reykjavik, Iceland
| | - Alessio Fasano
- Department of Pediatric Gastroenterology and Nutrition, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; (B.A.); (M.F.); (T.K.); (J.L.)
- Department of Pediatrics, Harvard Medical School, Harvard University, Boston, MA 02138, USA
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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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