Protein-protein interactions in the regulation of the cardiac sodium pump by phospholemman
Lead Research Organisation:
University of Dundee
Department Name: Molecular Medicine
Abstract
Hormones such as adrenaline act on the individual cells of the heart (?myocytes?) to cause the whole heart to change its behaviour according to the needs of the body. This is an exquisitely regulated process that means the heart?s output matches the body?s requirements. Understanding how exposure to hormones causes the whole heart to change its behaviour is crucial in developing an understanding of what can go wrong in heart disease.
Within a myocyte, hormonal signals are transmitted into the cell by groups of proteins (protein ?complexes?). The way these complexes work depends on the proteins involved. We have evidence that a protein complex forms between two proteins, dok-7 and phospholemman. Phospholemman is responsible for transmitting signals from hormones to another protein, the sodium pump, one of the most important enzymes in the heart. The sodium pump is responsible for moving ions across cell membranes, and indirectly it controls many processes that keep the heart alive and allow it to beat. Understanding the relationship between dok-7, phospholemman and the sodium pump will greatly improve our understanding of the way the heart responds to hormones, and possibly why diseased hearts are less able to do so.
Within a myocyte, hormonal signals are transmitted into the cell by groups of proteins (protein ?complexes?). The way these complexes work depends on the proteins involved. We have evidence that a protein complex forms between two proteins, dok-7 and phospholemman. Phospholemman is responsible for transmitting signals from hormones to another protein, the sodium pump, one of the most important enzymes in the heart. The sodium pump is responsible for moving ions across cell membranes, and indirectly it controls many processes that keep the heart alive and allow it to beat. Understanding the relationship between dok-7, phospholemman and the sodium pump will greatly improve our understanding of the way the heart responds to hormones, and possibly why diseased hearts are less able to do so.
Technical Summary
The primary active means of ion transport in the cardiomyocyte sarcolemma is the sodium pump. Acute regulation of the cardiac sodium pump by extracellular stimuli is crucial in allowing the heart to match its output to systemic requirements. Interventions that influence either sodium pump activity, or indirectly the transmembrane sodium gradient, profoundly affect cardiac function. Misregulation of the sodium pump can lead to cardiac insufficiency and heart failure. Phospholemman (PLM) is a novel sodium pump accessory protein that provides the link between kinase activity and modulation of sodium pump function. PLM exerts a tonic inhibition on the sodium pump that is relieved, and activity is in fact stimulated, by phosphorylation of PLM by a variety of kinases. Spatial and temporal control of signalling to PLM is key in controlling sodium pump function. The proteins that direct kinases and phosphatases to the PLM / sodium pump complex are unknown. We have preliminary evidence that the cytoplasmic scaffold protein dok-7, which contains N terminal plekstrin homology and phosphotyrosine binding domains interacts with PLM through its C terminus. Hence dok-7 has the potential to bring PLM together with signalling molecules. This proposal will characterise the functional consequences of this interaction, both in terms of kinase signalling to PLM, and PLM regulation of sodium pump function. Understanding the relationship between dok-7, PLM and the sodium pump will expand our knowledge of basic cardiac physiology and biochemistry, and may identify novel targets for treatment of cardiac ischemia, hypertrophy and heart failure.
Organisations
- University of Dundee, United Kingdom (Lead Research Organisation)
- Harvard University (Collaboration)
- University of Leeds, United Kingdom (Collaboration)
- University of Edinburgh, United Kingdom (Collaboration)
- Weizmann Institute of Science, Israel (Collaboration)
- University of Aberdeen, United Kingdom (Collaboration)
- University of Texas Southwestern Medical Center (Collaboration)
- University of Oslo, Norway (Collaboration)
- Karolinska Institute, Sweden (Collaboration)
- European Cooperation in Science and Technology (COST) (Collaboration)
- University of Duisburg-Essen, Germany (Collaboration)
- King's College London, United Kingdom (Collaboration)
People |
ORCID iD |
William Fuller (Principal Investigator) |
Publications

Boguslavskyi A
(2014)
Cardiac hypertrophy in mice expressing unphosphorylatable phospholemman.
in Cardiovascular research

El-Armouche A
(2011)
Phospholemman-dependent regulation of the cardiac Na/K-ATPase activity is modulated by inhibitor-1 sensitive type-1 phosphatase.
in FASEB journal : official publication of the Federation of American Societies for Experimental Biology

Fraser NJ
(2020)
Therapeutic targeting of protein S-acylation for the treatment of disease.
in Biochemical Society transactions

Fuller W
(2009)
FXYD1 phosphorylation in vitro and in adult rat cardiac myocytes: threonine 69 is a novel substrate for protein kinase C.
in American journal of physiology. Cell physiology

Fuller W
(2013)
Regulation of the cardiac sodium pump.
in Cellular and molecular life sciences : CMLS

Howie J
(2010)
Phospholemman Recruits Peroxiredoxin 6 to the Cardiac Sodium Pump
in Biophysical Journal

Howie J
(2013)
Regulation of the cardiac Na(+) pump by palmitoylation of its catalytic and regulatory subunits.
in Biochemical Society transactions

Howie J
(2010)
Peroxiredoxin 6 is Recruited to the Cardiac Sodium Pump Complex by Phospholemman.
in Circulation

Madhani M
(2010)
Phospholemman Ser69 phosphorylation contributes to sildenafil-induced cardioprotection against reperfusion injury.
in American journal of physiology. Heart and circulatory physiology

Pavlovic D
(2013)
Novel regulation of cardiac Na pump via phospholemman.
in Journal of molecular and cellular cardiology
Description | AHA Council on Basic Cardiovascular Sciences Travel Award/American Heart Association BCVS |
Amount | £1,000 (GBP) |
Organisation | American Heart Association (AHA) |
Sector | Charity/Non Profit |
Country | United States |
Start | 11/2010 |
End | 12/2010 |
Description | BHF PhD studentship |
Amount | £109,439 (GBP) |
Funding ID | FS/14/68/30988 |
Organisation | British Heart Foundation (BHF) |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 02/2015 |
End | 02/2018 |
Description | BHF Project Grant |
Amount | £81,726 (GBP) |
Funding ID | PG/12/6/29366 |
Organisation | British Heart Foundation (BHF) |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 09/2012 |
End | 12/2013 |
Description | BHF Project Grant |
Amount | £97,832 (GBP) |
Funding ID | PG/10/93/28650 |
Organisation | British Heart Foundation (BHF) |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 03/2011 |
End | 11/2012 |
Description | British Heart Foundation PhD studentship |
Amount | £104,227 (GBP) |
Funding ID | FS/13/22/30126 |
Organisation | British Heart Foundation (BHF) |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 07/2013 |
End | 08/2016 |
Description | Ninewells Hospital Anonymous Trust |
Amount | £9,746 (GBP) |
Organisation | Ninewells Hospital |
Sector | Hospitals |
Country | United Kingdom |
Start | 05/2012 |
End | 06/2014 |
Description | Ninwells Hospital Anonymous Trust Small Grants Scheme |
Amount | £10,000 (GBP) |
Organisation | Ninewells Hospital |
Sector | Hospitals |
Country | United Kingdom |
Start | 05/2014 |
End | 06/2015 |
Description | Project Grant |
Amount | £227,111 (GBP) |
Organisation | British Heart Foundation (BHF) |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 01/2016 |
End | 12/2018 |
Description | SULSA HTS Fund |
Amount | £18,519 (GBP) |
Organisation | Scottish Universities Life Sciences Alliance |
Sector | Academic/University |
Country | United Kingdom |
Start | 05/2012 |
End | 12/2014 |
Description | Small Research Grants Scheme/Ninewells Hospital Anonymous Trust |
Amount | £9,800 (GBP) |
Organisation | Ninewells Hospital |
Sector | Hospitals |
Country | United Kingdom |
Start | 05/2010 |
End | 06/2011 |
Description | Tenovus Scotland Small Research Grants Scheme |
Amount | £10,000 (GBP) |
Organisation | Tenovus Cancer Care |
Department | Tenovus Scotland |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 05/2008 |
End | 06/2009 |
Title | FXYD phosphospecific antibodies |
Description | Phosphospecific antibodies to PLM: S63, S68, T69, S68/T69 |
Type Of Material | Antibody |
Year Produced | 2010 |
Provided To Others? | Yes |
Impact | Publications, Collaborations and a commercialisation agreement with Badrilla |
Title | FXYD1 antibody |
Description | We have raised an antibody to phospholemman (FXYD1), the principal focus of this research project. |
Type Of Material | Antibody |
Year Produced | 2011 |
Provided To Others? | Yes |
Impact | There are few if any antibodies available that recognise an extracellular epitope of FXYD1. This is required for this project as the binding of all available antibodies to the intracellular region is influenced by post-translational modifications. |
Title | Tet-inducible cell lines |
Description | We have generated a panel of cell lines expressing wild type and palmitoylation point-mutants of FXYD1 under the control of a tetracycline sensitive promoter. These have been used to define the functional effect of palmitoylation of FXYD1 on the sodium pump, and the functional crosstalk between phosphorylation and palmitoylation of FXYD1 |
Type Of Material | Cell line |
Year Produced | 2013 |
Provided To Others? | Yes |
Impact | Publication PubMed id 21868384 |
URL | http://europepmc.org/abstract/MED/21868384 |
Description | Aberdeen |
Organisation | University of Aberdeen |
Department | Scottish Biologics Facility |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Evaluate monoclonal antibodies as sodium pump activators in assays in my lab |
Collaborator Contribution | Produce monoclonal antibodies by screening phage display library |
Impact | therapeutic monoclonal antibodies |
Start Year | 2012 |
Description | COST |
Organisation | European Cooperation in Science and Technology (COST) |
Country | Belgium |
Sector | Public |
PI Contribution | Secondary Proposer (COST Action Proposal oc-2013-2-17379, European Interdisciplinary Network on Na, K-ATPase in disease) |
Collaborator Contribution | Primary Proposer Dr Tsvetana Schyns-Liharska |
Impact | none - too early |
Start Year | 2013 |
Description | Duisberg Essen |
Organisation | University Duisburg-Essen |
Country | Germany |
Sector | Academic/University |
PI Contribution | Provided reagents |
Collaborator Contribution | none |
Impact | None |
Start Year | 2011 |
Description | Edinburgh |
Organisation | University of Edinburgh |
Department | Centre for Integrative Physiology |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Shared reagents and ideas |
Collaborator Contribution | Shared reagents |
Impact | ongoing |
Start Year | 2011 |
Description | Harvard |
Organisation | Harvard University |
Department | Harvard Medical School |
Country | United States |
Sector | Academic/University |
PI Contribution | Provided antibodies |
Collaborator Contribution | Evaluated antibodies |
Impact | none |
Start Year | 2010 |
Description | Karolinska |
Organisation | Karolinska Institute |
Department | Department of Molecular Medicine and Surgery |
Country | Sweden |
Sector | Academic/University |
PI Contribution | Provided antibody reagents |
Collaborator Contribution | Evaluated antibody reagents |
Impact | PubMed ID 21653224, |
Start Year | 2009 |
Description | King's College London |
Organisation | King's College London |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | This collaboration aims to define the physiological role of FXYD1. Physiological measurements are made at King's College London, and biochemical experiments at my laboratory in Dundee. Physiological data from London inform experimental design in my lab, and biochemical data from Dundee inform experimental approaches in London. Through investigating FXYD1 from a molecular to a whole animal level, we aim to define the physiological role of the biochemical relationships in which it participates. This relationship has led to one publication to which my laboratory was the principal contributor: FXYD1 phosphorylation in vitro and in adult rat cardiac myocytes: threonine 69 is a novel substrate for protein kinase C. Fuller W, Howie J, McLatchie LM, Weber RJ, Hastie CJ, Burness K, Pavlovic D, Shattock MJ. Am J Physiol Cell Physiol. 2009 Jun;296(6):C1346-55. PMID 19339511 |
Collaborator Contribution | Data sharing to inform each other's experimental design. Regular meetings to review experimental data and plan future investigations |
Impact | Publications PMID 18718984, 18065526, 19339511, 20543084, 21849407, 21868384, 22955490 |
Description | Norway |
Organisation | University of Oslo |
Department | Institute for Experimental Medical Research |
Country | Norway |
Sector | Academic/University |
PI Contribution | Provided reagents |
Collaborator Contribution | none |
Impact | Conference presentations, publications under preparation |
Start Year | 2013 |
Description | UT South Western |
Organisation | University of Texas Southwestern Medical Center |
Country | United States |
Sector | Academic/University |
PI Contribution | Biochemical information and expertise on the palmitoylation of the cardiac sodium pump catalytic and regulatory subunits. Research materials as they become available |
Collaborator Contribution | Functional information and expertise on the regulation of the cardiac sodium pump by palmitoylation. |
Impact | A PhD student from my lab will travel to Dallas |
Start Year | 2012 |
Description | University of Leeds |
Organisation | University of Leeds |
Department | Institute of Membrane and Systems Biology |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We have shared data and experience with the lab of Dr Sarah Calaghan in Leeds. She has provided advice on protocols for our experiments, and we have offered experience and and advice with the experiments ongoing in her laboratory. |
Collaborator Contribution | Provided experimental protocols |
Impact | Joint project grant application to the British Heart Foundation funded and now in progress |
Start Year | 2010 |
Description | Weizmann |
Organisation | Weizmann Institute of Science |
Country | Israel |
Sector | Academic/University |
PI Contribution | Provided reagents |
Collaborator Contribution | Provided reagents |
Impact | Publications under preparation |
Start Year | 2012 |
Description | Tour of Department |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | As part of of our engagement with the local community, groups that have contributed or are considering contributing to the local Tayside Institute for Cardiovascular Research charity are invited on tours of the department. The tour involves several demonstrations of the different types of research that are undertaken in the department, and a short seminar detailing our research achievements. The local Tayside Institute for Cardiovascular Research continues to fundraise successfully, and has recently received a substantial bequest in the will of an individual who was part of the 2007 department tour. |
Year(s) Of Engagement Activity | 2007,2009,2010,2011 |