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Swan AH, Schindler RFR, Savarese M, Mayer I, Rinné S, Bleser F, Schänzer A, Hahn A, Sabatelli M, Perna F, Chapman K, Pfuhl M, Spivey AC, Decher N, Udd B, Tasca G, Brand T. Differential effects of mutations of POPDC proteins on heteromeric interaction and membrane trafficking. Acta Neuropathol Commun 2023; 11:4. [PMID: 36624536 PMCID: PMC9830914 DOI: 10.1186/s40478-022-01501-w] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/22/2022] [Indexed: 01/11/2023] Open
Abstract
The Popeye domain containing (POPDC) genes encode sarcolemma-localized cAMP effector proteins. Mutations in blood vessel epicardial substance (BVES) also known as POPDC1 and POPDC2 have been associated with limb-girdle muscular dystrophy and cardiac arrhythmia. Muscle biopsies of affected patients display impaired membrane trafficking of both POPDC isoforms. Biopsy material of patients carrying mutations in BVES were immunostained with POPDC antibodies. The interaction of POPDC proteins was investigated by co-precipitation, proximity ligation, bioluminescence resonance energy transfer and bimolecular fluorescence complementation. Site-directed mutagenesis was utilised to map the domains involved in protein-protein interaction. Patients carrying a novel homozygous variant, BVES (c.547G > T, p.V183F) displayed only a skeletal muscle pathology and a mild impairment of membrane trafficking of both POPDC isoforms. In contrast, variants such as BVES p.Q153X or POPDC2 p.W188X were associated with a greater impairment of membrane trafficking. Co-transfection analysis in HEK293 cells revealed that POPDC proteins interact with each other through a helix-helix interface located at the C-terminus of the Popeye domain. Site-directed mutagenesis of an array of ultra-conserved hydrophobic residues demonstrated that some of them are required for membrane trafficking of the POPDC1-POPDC2 complex. Mutations in POPDC proteins that cause an impairment in membrane localization affect POPDC complex formation while mutations which leave protein-protein interaction intact likely affect some other essential function of POPDC proteins.
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Affiliation(s)
- Alexander H. Swan
- grid.7445.20000 0001 2113 8111National Heart and Lung Institute (NHLI), Imperial College London, London, UK ,grid.7445.20000 0001 2113 8111Department of Chemistry, Imperial College London, London, UK
| | - Roland F. R. Schindler
- grid.7445.20000 0001 2113 8111National Heart and Lung Institute (NHLI), Imperial College London, London, UK ,grid.434240.5Present Address: Assay Biology, Domainex Ltd, Cambridge, CB10 1XL UK
| | - Marco Savarese
- grid.7737.40000 0004 0410 2071Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Isabelle Mayer
- grid.7445.20000 0001 2113 8111National Heart and Lung Institute (NHLI), Imperial College London, London, UK
| | - Susanne Rinné
- grid.10253.350000 0004 1936 9756Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Felix Bleser
- grid.10253.350000 0004 1936 9756Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Anne Schänzer
- grid.8664.c0000 0001 2165 8627Institute of Neuropathology, Justus Liebig University Giessen, Giessen, Germany
| | - Andreas Hahn
- grid.8664.c0000 0001 2165 8627Department of Child Neurology, Justus Liebig University Giessen, Giessen, Germany
| | - Mario Sabatelli
- grid.8142.f0000 0001 0941 3192Department of Neurology, Universitá Cattolica del Sacro Cuore, Rome, Italy
| | - Francesco Perna
- grid.414603.4Dipartimento Di Scienze Cardiovascolari, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Kathryn Chapman
- grid.434240.5Present Address: Assay Biology, Domainex Ltd, Cambridge, CB10 1XL UK
| | - Mark Pfuhl
- grid.13097.3c0000 0001 2322 6764School of Cardiovascular Medicine and Sciences and Randall Centre, King’s College London, London, UK
| | - Alan C. Spivey
- grid.7445.20000 0001 2113 8111Department of Chemistry, Imperial College London, London, UK
| | - Niels Decher
- grid.8664.c0000 0001 2165 8627Institute of Neuropathology, Justus Liebig University Giessen, Giessen, Germany
| | - Bjarne Udd
- grid.7737.40000 0004 0410 2071Folkhälsan Research Center, University of Helsinki, Helsinki, Finland
| | - Giorgio Tasca
- grid.414603.4Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy ,grid.1006.70000 0001 0462 7212Present Address: John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trusts, Newcastle Upon Tyne, UK
| | - Thomas Brand
- grid.7445.20000 0001 2113 8111National Heart and Lung Institute (NHLI), Imperial College London, London, UK ,Imperial Centre of Translational and Experimental Medicine, Du Cane Road, London, W120NN UK
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Abstract
The Popeye domain containing (POPDC) genes encode transmembrane proteins, which are abundantly expressed in striated muscle cells. Hallmarks of the POPDC proteins are the presence of three transmembrane domains and the Popeye domain, which makes up a large part of the cytoplasmic portion of the protein and functions as a cAMP-binding domain. Interestingly, despite the prediction of structural similarity between the Popeye domain and other cAMP binding domains, at the protein sequence level they strongly differ from each other suggesting an independent evolutionary origin of POPDC proteins. Loss-of-function experiments in zebrafish and mouse established an important role of POPDC proteins for cardiac conduction and heart rate adaptation after stress. Loss-of function mutations in patients have been associated with limb-girdle muscular dystrophy and AV-block. These data suggest an important role of these proteins in the maintenance of structure and function of striated muscle cells.
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