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Quan C, Li M, Du Q, Chen Q, Wang H, Campbell D, Fang L, Xue B, MacKintosh C, Gao X, Ouyang K, Wang HY, Chen S. SPEG Controls Calcium Reuptake Into the Sarcoplasmic Reticulum Through Regulating SERCA2a by Its Second Kinase-Domain. Circ Res 2019; 124:712-726. [PMID: 30566039 DOI: 10.1161/circresaha.118.313916] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
RATIONALE SPEG (Striated muscle preferentially expressed protein kinase) has 2 kinase-domains and is critical for cardiac development and function. However, it is not clear how these 2 kinase-domains function to maintain cardiac performance. OBJECTIVE To determine the molecular functions of the 2 kinase-domains of SPEG. METHODS AND RESULTS A proteomics approach identified SERCA2a (sarcoplasmic/endoplasmic reticulum calcium ATPase 2a) as a protein interacting with the second kinase-domain but not the first kinase-domain of SPEG. Furthermore, the second kinase-domain of SPEG could phosphorylate Thr484 on SERCA2a, promote its oligomerization and increase calcium reuptake into the sarcoplasmic/endoplasmic reticulum in culture cells and primary neonatal rat cardiomyocytes. Phosphorylation of SERCA2a by SPEG enhanced its calcium-transporting activity without affecting its ATPase activity. Depletion of Speg in neonatal rat cardiomyocytes inhibited SERCA2a-Thr484 phosphorylation and sarcoplasmic reticulum calcium reuptake. Moreover, overexpression of SERCA2aThr484Ala mutant protein also slowed sarcoplasmic reticulum calcium reuptake in neonatal rat cardiomyocytes. In contrast, domain mapping and phosphorylation analysis revealed that the first kinase-domain of SPEG interacted and phosphorylated its recently identified substrate JPH2 (junctophilin-2). An inducible heart-specific Speg knockout mouse model was generated to further study this SPEG-SERCA2a signal nexus in vivo. Inducible deletion of Speg decreased SERCA2a-Thr484 phosphorylation and its oligomerization in the heart. Importantly, inducible deletion of Speg inhibited SERCA2a calcium-transporting activity and impaired calcium reuptake into the sarcoplasmic reticulum in cardiomyocytes, which preceded morphological and functional alterations of the heart and eventually led to heart failure in adult mice. CONCLUSIONS Our data demonstrate that the 2 kinase-domains of SPEG may play distinct roles to regulate cardiac function. The second kinase-domain of SPEG is a critical regulator for SERCA2a. Our findings suggest that SPEG may serve as a new target to modulate SERCA2a activation for treatment of heart diseases with impaired calcium homeostasis.
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Affiliation(s)
- Chao Quan
- From the State Key Laboratory of Pharmaceutical Biotechnology, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center (C.Q., M.L., Q.D., Q.L.C., X.G., H.Y.W., S.C.), Nanjing University, China
| | - Min Li
- From the State Key Laboratory of Pharmaceutical Biotechnology, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center (C.Q., M.L., Q.D., Q.L.C., X.G., H.Y.W., S.C.), Nanjing University, China
| | - Qian Du
- From the State Key Laboratory of Pharmaceutical Biotechnology, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center (C.Q., M.L., Q.D., Q.L.C., X.G., H.Y.W., S.C.), Nanjing University, China
| | - Qiaoli Chen
- From the State Key Laboratory of Pharmaceutical Biotechnology, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center (C.Q., M.L., Q.D., Q.L.C., X.G., H.Y.W., S.C.), Nanjing University, China
| | - Hong Wang
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University, Shenzhen, China (H.W., K.F.O.Y.)
| | - David Campbell
- MRC Protein Phosphorylation and Ubiquitylation Unit (D.C.), School of Life Sciences, University of Dundee, Scotland, United Kingdom
| | - Lei Fang
- School of Medicine (L.F., B.X.), Nanjing University, China
| | - Bin Xue
- School of Medicine (L.F., B.X.), Nanjing University, China
| | - Carol MacKintosh
- Division of Cell and Developmental Biology (C.M.), School of Life Sciences, University of Dundee, Scotland, United Kingdom
| | - Xiang Gao
- From the State Key Laboratory of Pharmaceutical Biotechnology, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center (C.Q., M.L., Q.D., Q.L.C., X.G., H.Y.W., S.C.), Nanjing University, China
| | - Kunfu Ouyang
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University, Shenzhen, China (H.W., K.F.O.Y.)
| | - Hong Yu Wang
- From the State Key Laboratory of Pharmaceutical Biotechnology, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center (C.Q., M.L., Q.D., Q.L.C., X.G., H.Y.W., S.C.), Nanjing University, China
| | - Shuai Chen
- From the State Key Laboratory of Pharmaceutical Biotechnology, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center (C.Q., M.L., Q.D., Q.L.C., X.G., H.Y.W., S.C.), Nanjing University, China
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Lohan J, Culligan K, Ohlendieck K. Deficiency in Cardiac Dystrophin Affects the Abundance of the $\alpha$ -/ $\beta$ -Dystroglycan Complex. J Biomed Biotechnol 2005; 2005:28-36. [PMID: 15689636 PMCID: PMC1138265 DOI: 10.1155/jbb.2005.28] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Although Duchenne muscular dystrophy is primarily categorised as a skeletal muscle disease, deficiency in the membrane cytoskeletal protein dystrophin also affects the heart. The central transsarcolemmal linker between the actin membrane cytoskeleton and the extracellular matrix is represented by the dystrophin-associated dystroglycans. Chemical cross-linking analysis revealed no significant differences in the dimeric status of the $\alpha$ -/ $\beta$ -dystroglycan subcomplex in the dystrophic mdx heart as compared to normal cardiac tissue. In analogy to skeletal muscle fibres, heart muscle also exhibited a greatly reduced abundance of both dystroglycans in dystrophin-deficient cells. Immunoblotting demonstrated that the degree of reduction in $\alpha$ -dystroglycan is more pronounced in matured mdx skeletal muscle as contrasted to the mdx heart. The fact that the deficiency in dystrophin triggers a similar pathobiochemical response in both types of muscle suggests that the cardiomyopathic complications observed in $x$ -linked muscular dystrophy might be initiated by the loss of the dystrophin-associated surface glycoprotein complex.
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Affiliation(s)
- James Lohan
- Department of Biology, Faculty of Science, National University of Ireland, Maynooth, County
Kildare, Ireland
| | - Kevin Culligan
- Department of Biology, Faculty of Science, National University of Ireland, Maynooth, County
Kildare, Ireland
| | - Kay Ohlendieck
- Department of Biology, Faculty of Science, National University of Ireland, Maynooth, County
Kildare, Ireland
- *Kay Ohlendieck:
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