1
|
Cleary SR, Teng ACT, Kongmeneck AD, Fang X, Phillips TA, Cho EE, Kekenes-Huskey P, Gramolini AO, Robia SL. Dilated cardiomyopathy variant R14del increases phospholamban pentamer stability, blunting dynamic regulation of cardiac calcium handling. bioRxiv 2023:2023.05.26.542463. [PMID: 37292897 PMCID: PMC10245957 DOI: 10.1101/2023.05.26.542463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The sarco(endo)plasmic reticulum Ca 2+ ATPase (SERCA) is a membrane transporter that creates and maintains intracellular Ca 2+ stores. In the heart, SERCA is regulated by an inhibitory interaction with the monomeric form of the transmembrane micropeptide phospholamban (PLB). PLB also forms avid homo-pentamers, and dynamic exchange of PLB between pentamers and the regulatory complex with SERCA is an important determinant of cardiac responsiveness to exercise. Here, we investigated two naturally occurring pathogenic mutations of PLB, a cysteine substitution of arginine 9 (R9C) and an in-frame deletion of arginine 14 (R14del). Both mutations are associated with dilated cardiomyopathy. We previously showed that the R9C mutation causes disulfide crosslinking and hyperstabilization of pentamers. While the pathogenic mechanism of R14del is unclear, we hypothesized that this mutation may also alter PLB homo-oligomerization and disrupt the PLB-SERCA regulatory interaction. SDS-PAGE revealed a significantly increased pentamer:monomer ratio for R14del-PLB when compared to WT-PLB. In addition, we quantified homo-oligomerization and SERCA-binding in live cells using fluorescence resonance energy transfer (FRET) microscopy. R14del-PLB showed an increased affinity for homo-oligomerization and decreased binding affinity for SERCA compared to WT, suggesting that, like R9C, the R14del mutation stabilizes PLB in its pentameric form, decreasing its ability to regulate SERCA. Moreover, the R14del mutation reduces the rate of PLB unbinding from the pentamer after a transient Ca 2+ elevation, limiting the rate of re-binding to SERCA. A computational model predicted that hyperstabilization of PLB pentamers by R14del impairs the ability of cardiac Ca 2+ handling to respond to changing heart rates between rest and exercise. We postulate that impaired responsiveness to physiological stress contributes to arrhythmogenesis in human carriers of the R14del mutation.
Collapse
|
2
|
Teng ACT, Tavassoli M, Shrestha S, Marks RM, McFadden MJ, Evagelou SL, Lindsay K, Vandenbelt A, Li W, Ivakine E, Cohn R, Santerre JP, Gramolini AO. An efficient and cost-effective purification protocol for Staphylococcus aureus Cas9 nuclease. STAR Protoc 2023; 4:101933. [PMID: 36574341 PMCID: PMC9813775 DOI: 10.1016/j.xpro.2022.101933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/10/2022] [Accepted: 11/23/2022] [Indexed: 12/27/2022] Open
Abstract
Here, we describe a protocol for purifying functional clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) from Staphylococcus aureus within 24 h and over 90% purity. SaCas9 purification begins with immobilized metal affinity chromatography, followed by cation exchange chromatography, and ended with centrifugal concentrators. The simplicity, cost-effectiveness, and reproducibility of such protocols will enable general labs to produce a sizable amount of Cas9 proteins, further accelerating CRISPR research.
Collapse
Affiliation(s)
- Allen C T Teng
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Marjan Tavassoli
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Suja Shrestha
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1X3, Canada
| | - Ryan M Marks
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Meghan J McFadden
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Sonia L Evagelou
- Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Kyle Lindsay
- Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Ava Vandenbelt
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, ON M5S 2W6, Canada
| | - Wenping Li
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Evgueni Ivakine
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Ronald Cohn
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - J Paul Santerre
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1X3, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Anthony O Gramolini
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, 661 University Avenue, 14th Floor, Toronto, ON M5G 1M1, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
| |
Collapse
|
3
|
Teng ACT, Gu L, Di Paola M, Lakin R, Williams ZJ, Au A, Chen W, Callaghan NI, Zadeh FH, Zhou YQ, Fatah M, Chatterjee D, Jourdan LJ, Liu J, Simmons CA, Kislinger T, Yip CM, Backx PH, Gourdie RG, Hamilton RM, Gramolini AO. Tmem65 is critical for the structure and function of the intercalated discs in mouse hearts. Nat Commun 2022; 13:6166. [PMID: 36257954 PMCID: PMC9579145 DOI: 10.1038/s41467-022-33303-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/07/2022] [Indexed: 12/24/2022] Open
Abstract
The intercalated disc (ICD) is a unique membrane structure that is indispensable to normal heart function, yet its structural organization is not completely understood. Previously, we showed that the ICD-bound transmembrane protein 65 (Tmem65) was required for connexin43 (Cx43) localization and function in cultured mouse neonatal cardiomyocytes. Here, we investigate the functional and cellular effects of Tmem65 reductions on the myocardium in a mouse model by injecting CD1 mouse pups (3-7 days after birth) with recombinant adeno-associated virus 9 (rAAV9) harboring Tmem65 shRNA, which reduces Tmem65 expression by 90% in mouse ventricles compared to scrambled shRNA injection. Tmem65 knockdown (KD) results in increased mortality which is accompanied by eccentric hypertrophic cardiomyopathy within 3 weeks of injection and progression to dilated cardiomyopathy with severe cardiac fibrosis by 7 weeks post-injection. Tmem65 KD hearts display depressed hemodynamics as measured echocardiographically as well as slowed conduction in optical recording accompanied by prolonged PR intervals and QRS duration in electrocardiograms. Immunoprecipitation and super-resolution microscopy demonstrate a physical interaction between Tmem65 and sodium channel β subunit (β1) in mouse hearts and this interaction appears to be required for both the establishment of perinexal nanodomain structure and the localization of both voltage-gated sodium channel 1.5 (NaV1.5) and Cx43 to ICDs. Despite the loss of NaV1.5 at ICDs, whole-cell patch clamp electrophysiology did not reveal reductions in Na+ currents but did show reduced Ca2+ and K+ currents in Tmem65 KD cardiomyocytes in comparison to control cells. We conclude that disrupting Tmem65 function results in impaired ICD structure, abnormal cardiac electrophysiology, and ultimately cardiomyopathy.
Collapse
Affiliation(s)
- Allen C T Teng
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada.
| | - Liyang Gu
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
| | - Michelle Di Paola
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
| | - Robert Lakin
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Zachary J Williams
- The Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute at Virginia Tech. Carilion, Roanoke, VA, 24016, USA
- Translational Biology Medicine and Health Graduate Program, Virginia Tech, Roanoke, VA, 24016, USA
| | - Aaron Au
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Wenliang Chen
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Neal I Callaghan
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
| | - Farigol Hakem Zadeh
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
| | - Yu-Qing Zhou
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
| | - Meena Fatah
- The Labatt Family Heart Centre (Dept. of Pediatrics) and Translational Medicine, The Hospital for Sick Children & Research Institute, University of Toronto, Toronto, ON., M5G 1X8, Canada
| | - Diptendu Chatterjee
- The Labatt Family Heart Centre (Dept. of Pediatrics) and Translational Medicine, The Hospital for Sick Children & Research Institute, University of Toronto, Toronto, ON., M5G 1X8, Canada
| | - L Jane Jourdan
- The Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute at Virginia Tech. Carilion, Roanoke, VA, 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24060, USA
| | - Jack Liu
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Craig A Simmons
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
| | - Thomas Kislinger
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Christopher M Yip
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Peter H Backx
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Robert G Gourdie
- The Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute at Virginia Tech. Carilion, Roanoke, VA, 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24060, USA
| | - Robert M Hamilton
- The Labatt Family Heart Centre (Dept. of Pediatrics) and Translational Medicine, The Hospital for Sick Children & Research Institute, University of Toronto, Toronto, ON., M5G 1X8, Canada
| | - Anthony O Gramolini
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada.
| |
Collapse
|
4
|
Shrestha S, McFadden MJ, Teng ACT, Chang PDM, Deng J, Wong TWY, Cohn RD, Ivakine EA, Gramolini AO, Santerre JP. Self-Assembled Oligo-Urethane Nanoparticles: Their Characterization and Use for the Delivery of Active Biomolecules into Mammalian Cells. ACS Appl Mater Interfaces 2021; 13:58352-58368. [PMID: 34873903 DOI: 10.1021/acsami.1c17868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Developing safe and effective strategies to deliver biomolecules such as oligonucleotides and proteins into cells has grown in importance over recent years, with an increasing demand for non-viral methods that enable clinical translation. Here, we investigate uniquely configured oligo-urethane nanoparticles based on synthetic chemistries that minimize the release of pro-inflammatory biomarkers from immune cells, show low cytotoxicity in a broad range of cells, and efficiently deliver oligonucleotides and proteins into mammalian cells. The mechanism of cell uptake for the self-assembled oligo-urethane nanoparticles was shown to be directed by caveolae-dependent endocytosis in murine myoblasts (C2C12) cells. Inhibiting caveolae functions with genistein and methyl-β-cyclodextrin limited nanoparticle internalization. The nanoparticles showed a very high delivery efficiency for the genetic material (a 47-base oligonucleotide) (∼80% incorporation into cells) as well as the purified protein (full length firefly luciferase, 67 kDa) into human embryonic kidney (HEK293T) cells. Luciferase enzyme activity in HEK293T cells demonstrated that intact and functional proteins could be delivered and showed a significant extension of activity retention up to 24 h, well beyond the 2 h half-life of the free enzyme. This study introduces a novel self-assembled oligo-urethane nanoparticle delivery platform with very low associated production costs, enabled by their scalable chemistry (the benchwork cost is $ 0.152/mg vs $ 974.6/mg for typical lipid carriers) that has potential to deliver both oligonucleotides and proteins for biomedical purposes.
Collapse
Affiliation(s)
- Suja Shrestha
- Faculty of Dentistry, University of Toronto, Toronto M5G 1G6, Ontario, Canada
- Translational Biology and Engineering Program and Ted Rogers Centre for Heart Research, Toronto M5G 1M1, Ontario, Canada
| | - Meghan J McFadden
- Translational Biology and Engineering Program and Ted Rogers Centre for Heart Research, Toronto M5G 1M1, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto M5S 3G9, Ontario, Canada
| | - Allen C T Teng
- Translational Biology and Engineering Program and Ted Rogers Centre for Heart Research, Toronto M5G 1M1, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto M5S 1A8, Ontario, Canada
| | - Patrick Dong Min Chang
- Translational Biology and Engineering Program and Ted Rogers Centre for Heart Research, Toronto M5G 1M1, Ontario, Canada
- Department of Chemical Engineering & Applied Chemistry, Faculty of Engineering, University of Toronto, Toronto M5S 3E5, Canada
| | - Joyce Deng
- Translational Biology and Engineering Program and Ted Rogers Centre for Heart Research, Toronto M5G 1M1, Ontario, Canada
| | - Tatianna W Y Wong
- Genetics & Genome Biology Program, The Hospital for Sick Children, Toronto M5G 0A4, Ontario, Canada
| | - Ronald D Cohn
- Department of Molecular & Medical Genetics and Paediatrics, Faculty of Medicine, University of Toronto, Toronto M5S 1A8, Ontario, Canada
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto M5G 0A4, Ontario, Canada
| | - Evgueni A Ivakine
- Department of Physiology, University of Toronto, Toronto M5S 1A8, Ontario, Canada
- Genetics & Genome Biology Program, The Hospital for Sick Children, Toronto M5G 0A4, Ontario, Canada
| | - Anthony O Gramolini
- Translational Biology and Engineering Program and Ted Rogers Centre for Heart Research, Toronto M5G 1M1, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto M5S 1A8, Ontario, Canada
| | - J Paul Santerre
- Faculty of Dentistry, University of Toronto, Toronto M5G 1G6, Ontario, Canada
- Translational Biology and Engineering Program and Ted Rogers Centre for Heart Research, Toronto M5G 1M1, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto M5S 3G9, Ontario, Canada
| |
Collapse
|
5
|
Braun JL, Teng ACT, Geromella MS, Ryan CR, Fenech RK, MacPherson REK, Gramolini AO, Fajardo VA. Neuronatin promotes SERCA uncoupling and its expression is altered in skeletal muscles of high-fat diet-fed mice. FEBS Lett 2021; 595:2756-2767. [PMID: 34693525 DOI: 10.1002/1873-3468.14213] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 10/07/2021] [Accepted: 10/15/2021] [Indexed: 11/09/2022]
Abstract
Neuronatin (NNAT) is a transmembrane protein in the endoplasmic reticulum involved in metabolic regulation. It shares sequence homology with sarcolipin (SLN), which negatively regulates the sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA) that maintains energy homeostasis in muscles. Here, we examined whether NNAT could uncouple the Ca2+ transport activity of SERCA from ATP hydrolysis, similarly to SLN. NNAT significantly reduced Ca2+ uptake without altering SERCA activity, ultimately lowering the apparent coupling ratio of SERCA. This effect of NNAT was reversed by the adenylyl cyclase activator forskolin. Furthermore, soleus muscles from high fat diet (HFD)-fed mice showed a significant downregulation in NNAT content compared with chow-fed mice, whereas an upregulation in NNAT content was observed in fast-twitch muscles from HFD- versus chow- fed mice. Therefore, NNAT is a SERCA uncoupler in cells and may function in adaptive thermogenesis.
Collapse
Affiliation(s)
- Jessica L Braun
- Department of Kinesiology, Brock University, St. Catharines, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Canada.,Centre for Neuroscience, Brock University, St. Catharines, Canada
| | - Allen C T Teng
- Department of Physiology, University of Toronto, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Canada
| | - Mia S Geromella
- Department of Kinesiology, Brock University, St. Catharines, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Canada.,Centre for Neuroscience, Brock University, St. Catharines, Canada
| | - Chantal R Ryan
- Centre for Neuroscience, Brock University, St. Catharines, Canada.,Department of Health Sciences, Brock University, St. Catharines, Canada
| | - Rachel K Fenech
- Centre for Neuroscience, Brock University, St. Catharines, Canada.,Department of Health Sciences, Brock University, St. Catharines, Canada
| | - Rebecca E K MacPherson
- Centre for Neuroscience, Brock University, St. Catharines, Canada.,Department of Health Sciences, Brock University, St. Catharines, Canada
| | - Anthony O Gramolini
- Department of Physiology, University of Toronto, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Canada
| | - Val A Fajardo
- Department of Kinesiology, Brock University, St. Catharines, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Canada.,Centre for Neuroscience, Brock University, St. Catharines, Canada
| |
Collapse
|
6
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
7
|
Sharma P, Abbasi C, Lazic S, Teng ACT, Wang D, Dubois N, Ignatchenko V, Wong V, Liu J, Araki T, Tiburcy M, Ackerley C, Zimmermann WH, Hamilton R, Sun Y, Liu PP, Keller G, Stagljar I, Scott IC, Kislinger T, Gramolini AO. Evolutionarily conserved intercalated disc protein Tmem65 regulates cardiac conduction and connexin 43 function. Nat Commun 2015; 6:8391. [PMID: 26403541 DOI: 10.1038/ncomms9391] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 08/18/2015] [Indexed: 02/07/2023] Open
Abstract
Membrane proteins are crucial to heart function and development. Here we combine cationic silica-bead coating with shotgun proteomics to enrich for and identify plasma membrane-associated proteins from primary mouse neonatal and human fetal ventricular cardiomyocytes. We identify Tmem65 as a cardiac-enriched, intercalated disc protein that increases during development in both mouse and human hearts. Functional analysis of Tmem65 both in vitro using lentiviral shRNA-mediated knockdown in mouse cardiomyocytes and in vivo using morpholino-based knockdown in zebrafish show marked alterations in gap junction function and cardiac morphology. Molecular analyses suggest that Tmem65 interaction with connexin 43 (Cx43) is required for correct localization of Cx43 to the intercalated disc, since Tmem65 deletion results in marked internalization of Cx43, a shorter half-life through increased degradation, and loss of Cx43 function. Our data demonstrate that the membrane protein Tmem65 is an intercalated disc protein that interacts with and functionally regulates ventricular Cx43.
Collapse
Affiliation(s)
- Parveen Sharma
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Cynthia Abbasi
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Savo Lazic
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Allen C T Teng
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Dingyan Wang
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Nicole Dubois
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Vladimir Ignatchenko
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Victoria Wong
- Departments of Molecular Genetics and Biochemistry, Donnelly Centre,, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Jun Liu
- Department of Mechanical and Industrial Engineering, Advanced Micro and Nanosystems Laboratory, University of Toronto, Toronto, Ontario, Canada M5S 3G8
| | - Toshiyuki Araki
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Malte Tiburcy
- Institute of Pharmacology, University Medical Center Göttingen and DZHK (German Center for Cardiovascular Research) partner site Göttingen, Göttingen 37075, Germany
| | - Cameron Ackerley
- The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Wolfram H Zimmermann
- Institute of Pharmacology, University Medical Center Göttingen and DZHK (German Center for Cardiovascular Research) partner site Göttingen, Göttingen 37075, Germany
| | - Robert Hamilton
- The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada M5G 1L7
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, Advanced Micro and Nanosystems Laboratory, University of Toronto, Toronto, Ontario, Canada M5S 3G8
| | - Peter P Liu
- Toronto General Hospital, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Gordon Keller
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Igor Stagljar
- Departments of Molecular Genetics and Biochemistry, Donnelly Centre,, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Ian C Scott
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada M5G 1L7
| | - Thomas Kislinger
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada M5G 1L7.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 2M9
| | - Anthony O Gramolini
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7.,Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada M5G 1L7
| |
Collapse
|
8
|
Almontashiri NAM, Chen HH, Mailloux RJ, Tatsuta T, Teng ACT, Mahmoud AB, Ho T, Stewart NAS, Rippstein P, Harper ME, Roberts R, Willenborg C, Erdmann J, Pastore A, McBride HM, Langer T, Stewart AFR. SPG7 variant escapes phosphorylation-regulated processing by AFG3L2, elevates mitochondrial ROS, and is associated with multiple clinical phenotypes. Cell Rep 2014; 7:834-47. [PMID: 24767997 DOI: 10.1016/j.celrep.2014.03.051] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/06/2014] [Accepted: 03/20/2014] [Indexed: 02/01/2023] Open
Abstract
Mitochondrial production of reactive oxygen species (ROS) affects many processes in health and disease. SPG7 assembles with AFG3L2 into the mAAA protease at the inner membrane of mitochondria, degrades damaged proteins, and regulates the synthesis of mitochondrial ribosomes. SPG7 is cleaved and activated by AFG3L2 upon assembly. A variant in SPG7 that replaces arginine 688 with glutamine (Q688) is associated with several phenotypes, including toxicity of chemotherapeutic agents, type 2 diabetes mellitus, and (as reported here) coronary artery disease. We demonstrate that SPG7 processing is regulated by tyrosine phosphorylation of AFG3L2. Carriers of Q688 bypass this regulation and constitutively process and activate SPG7 mAAA protease. Cells expressing Q688 produce higher ATP levels and ROS, promoting cell proliferation. Our results thus reveal an unexpected link between the phosphorylation-dependent regulation of the mitochondria mAAA protease affecting ROS production and several clinical phenotypes.
Collapse
Affiliation(s)
- Naif A M Almontashiri
- Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute, Ottawa, ON K1Y, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Center for Genetics and Inherited Diseases, Department of Applied Medical Sciences, Taibah University, Almedinah, P.O. Box 41477, Saudi Arabia
| | - Hsiao-Huei Chen
- Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
| | - Ryan J Mailloux
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Takashi Tatsuta
- Institute for Genetics, University of Cologne, Cologne 50674, Germany
| | - Allen C T Teng
- Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute, Ottawa, ON K1Y, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Ahmad B Mahmoud
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Tiffany Ho
- Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute, Ottawa, ON K1Y, Canada
| | - Nicolas A S Stewart
- Center for Clinical Pharmacology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Peter Rippstein
- Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute, Ottawa, ON K1Y, Canada
| | - Mary Ellen Harper
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Robert Roberts
- Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute, Ottawa, ON K1Y, Canada
| | | | | | | | - Annalisa Pastore
- National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | | | - Thomas Langer
- Institute for Genetics, University of Cologne, Cologne 50674, Germany
| | - Alexandre F R Stewart
- Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute, Ottawa, ON K1Y, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
| |
Collapse
|
9
|
Mulyar OA, Teng ACT, Gramolini AO. A proteomic interrogation of Cryptococcus neoformans: interaction networks for calcineurin in a heated environment. Expert Rev Proteomics 2012; 9:13-5. [PMID: 22292819 DOI: 10.1586/epr.11.76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Calcineurin (CN) is a calcium- and calmodulin-dependent protein phosphatase that consists of a catalytic subunit (calcineurin A [CnA]) and a calcium-binding, regulatory subunit (calcineurin B [CnB]). Calcineurin has been shown to be involved in a number of cellular processes, and aberrant signaling has been linked to multiple human diseases, such as cardiac hypertrophy and diabetes. Recent studies demonstrated that CN was involved in the survival of Cryptococcus neoformans, a fungal pathogen that infects humans, especially patients who are immunocompromised. CN appears to be essential for the survival and virulence of C. neoformans; however, the underlying mechanisms remain largely unknown. The Heitman laboratory recently identified a group of potential CnA-interacting proteins in C. neoformans during heat stress, and demonstrated an interaction of CnA with Sec28 and Sec13, which represent COPI and COPII protein complex members, respectively. The COP protein complexes are key proteins involved in intracellular endoplasmic reticulum and golgi protein trafficking. The results from the Heitman group suggest that CN interacts with components of the endoplasmic reticulum and the golgi during heat stress in C. neoformans and could highlight potential mechanisms by which these microbes could be targeted.
Collapse
Affiliation(s)
- Oleh A Mulyar
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | | | | |
Collapse
|
10
|
Teng ACT, Al-montashiri NAM, Cheng BLM, Lou P, Ozmizrak P, Chen HH, Stewart AFR. Identification of a phosphorylation-dependent nuclear localization motif in interferon regulatory factor 2 binding protein 2. PLoS One 2011; 6:e24100. [PMID: 21887377 PMCID: PMC3162591 DOI: 10.1371/journal.pone.0024100] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 07/31/2011] [Indexed: 12/29/2022] Open
Abstract
Background Interferon regulatory factor 2 binding protein 2 (IRF2BP2) is a muscle-enriched transcription factor required to activate vascular endothelial growth factor-A (VEGFA) expression in muscle. IRF2BP2 is found in the nucleus of cardiac and skeletal muscle cells. During the process of skeletal muscle differentiation, some IRF2BP2 becomes relocated to the cytoplasm, although the functional significance of this relocation and the mechanisms that control nucleocytoplasmic localization of IRF2BP2 are not yet known. Methodology/Principal Findings Here, by fusing IRF2BP2 to green fluorescent protein and testing a series of deletion and site-directed mutagenesis constructs, we mapped the nuclear localization signal (NLS) to an evolutionarily conserved sequence 354ARKRKPSP361 in IRF2BP2. This sequence corresponds to a classical nuclear localization motif bearing positively charged arginine and lysine residues. Substitution of arginine and lysine with negatively charged aspartic acid residues blocked nuclear localization. However, these residues were not sufficient because nuclear targeting of IRF2BP2 also required phosphorylation of serine 360 (S360). Many large-scale phosphopeptide proteomic studies had reported previously that serine 360 of IRF2BP2 is phosphorylated in numerous human cell types. Alanine substitution at this site abolished IRF2BP2 nuclear localization in C2C12 myoblasts and CV1 cells. In contrast, substituting serine 360 with aspartic acid forced nuclear retention and prevented cytoplasmic redistribution in differentiated C2C12 muscle cells. As for the effects of these mutations on VEGFA promoter activity, the S360A mutation interfered with VEGFA activation, as expected. Surprisingly, the S360D mutation also interfered with VEGFA activation, suggesting that this mutation, while enforcing nuclear entry, may disrupt an essential activation function of IRF2BP2. Conclusions/Significance Nuclear localization of IRF2BP2 depends on phosphorylation near a conserved NLS. Changes in phosphorylation status likely control nucleocytoplasmic localization of IRF2BP2 during muscle differentiation.
Collapse
Affiliation(s)
- Allen C. T. Teng
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Naif A. M. Al-montashiri
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Brian L. M. Cheng
- University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Philip Lou
- University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Pinar Ozmizrak
- University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Hsiao-Huei Chen
- University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Alexandre F. R. Stewart
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
| |
Collapse
|
11
|
Teng ACT, Kuraitis D, Deeke SA, Ahmadi A, Dugan SG, Cheng BLM, Crowson MG, Burgon PG, Suuronen EJ, Chen HH, Stewart AFR. IRF2BP2 is a skeletal and cardiac muscle-enriched ischemia-inducible activator of VEGFA expression. FASEB J 2010; 24:4825-34. [PMID: 20702774 DOI: 10.1096/fj.10-167049] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We sought to identify an essential component of the TEAD4/VGLL4 transcription factor complex that controls vascular endothelial growth factor A (VEGFA) expression in muscle. A yeast 2-hybrid screen was used to clone a novel component of the TEAD4 complex from a human heart cDNA library. We identified interferon response factor 2 binding protein 2 (IRF2BP2) and confirmed its presence in the TEAD4/VGLL4 complex in vivo by coimmunoprecipitation and mammalian 2-hybrid assays. Coexpression of IRF2BP2 with TEAD4/VGLL4 or TEAD1 alone potently activated, whereas knockdown of IRF2BP2 reduced, VEGFA expression in C(2)C(12) muscle cells. Thus, IRF2BP2 is required to activate VEGFA expression. In mouse embryos, IRF2BP2 was ubiquitously expressed but became progressively enriched in the fetal heart, skeletal muscles, and lung. Northern blot analysis revealed high levels of IRF2BP2 mRNA in adult human heart and skeletal muscles, but immunoblot analysis showed low levels of IRF2BP2 protein in skeletal muscle, indicating post-transcriptional regulation of IRF2BP2 expression. IRF2BP2 protein levels are markedly increased by ischemia in skeletal and cardiac muscle compared to normoxic controls. IRF2BP2 is a novel ischemia-induced coactivator of VEGFA expression that may contribute to revascularization of ischemic cardiac and skeletal muscles.
Collapse
Affiliation(s)
- Allen C T Teng
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Teng ACT, Kuraitis D, Deeke SA, Ahmadi A, Dugan SG, Cheng BLM, Crowson MG, Burgon PG, Suuronen EJ, Chen HH, Stewart AFR. IRF2BP2 is a skeletal and cardiac muscle‐enriched ischemia‐inducible activator of VEGFA expression. FASEB J 2010. [DOI: 10.1096/fj.10.167049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
| | - Drew Kuraitis
- University of Ottawa Heart Institute Ottawa Ontario Canada
| | | | - Ali Ahmadi
- University of Ottawa Heart Institute Ottawa Ontario Canada
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Teng ACT, Adamo K, Tesson F, Stewart AFR. Functional characterization of a promoter polymorphism that drives ACSL5 gene expression in skeletal muscle and associates with diet-induced weight loss. FASEB J 2009; 23:1705-9. [PMID: 19218499 DOI: 10.1096/fj.08-120998] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diet-induced weight loss is affected by a wide range of factors, including genetic variation. Identifying functional polymorphisms will help to elucidate mechanisms that account for variation in dietary metabolism. Previously, we reported a strong association between a common single nucleotide polymorphism (SNP) rs2419621 (C>T) in the promoter of acyl-CoA synthetase long chain 5 (ACSL5), rapid weight loss in obese Caucasian females, and elevated ACSL5 mRNA levels in skeletal muscle biopsies. Here, we showed by electrophoretic mobility shift assay (EMSA) that the T allele creates a functional cis-regulatory E-box element (CANNTG) that is recognized by the myogenic regulatory factor MyoD. The T allele promoted MyoD-dependent activation of a 1089-base pair ACSL5 promoter fragment in nonmuscle CV1 cells. Differentiation of skeletal myoblasts significantly elevated expression of the ACSL5 promoter. The T allele sustained promoter activity 48 h after differentiation, whereas the C allele showed a significant decline. These results reveal a mechanism for elevated transcription of ACSL5 in skeletal muscle of carriers of the rs2419621(T) allele, associated with more rapid diet-induced weight loss. Natural selection favoring promoter polymorphisms that reduced expression of catabolic genes in skeletal muscle likely accounts for the resistance of obese individuals to dietary intervention.
Collapse
Affiliation(s)
- Allen C T Teng
- Department of Biochemistry, Microbiology, and Immunology, Program of Human and Molecular Genetics, Faculty of Medicine, University of Ottawa, Ontario, Canada
| | | | | | | |
Collapse
|