1
|
Sitsel A, De Raeymaecker J, Drachmann ND, Derua R, Smaardijk S, Andersen JL, Vandecaetsbeek I, Chen J, De Maeyer M, Waelkens E, Olesen C, Vangheluwe P, Nissen P. Structures of the heart specific SERCA2a Ca 2+-ATPase. EMBO J 2019; 38:embj.2018100020. [PMID: 30777856 DOI: 10.15252/embj.2018100020] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 12/29/2018] [Accepted: 01/10/2019] [Indexed: 12/11/2022] Open
Abstract
The sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) performs active reuptake of cytoplasmic Ca2+ and is a major regulator of cardiac muscle contractility. Dysfunction or dysregulation of SERCA2a is associated with heart failure, while restoring its function is considered as a therapeutic strategy to restore cardiac performance. However, its structure has not yet been determined. Based on native, active protein purified from pig ventricular muscle, we present the first crystal structures of SERCA2a, determined in the CPA-stabilized E2-AlF4- form (3.3 Å) and the Ca2+-occluded [Ca2]E1-AMPPCP form (4.0 Å). The structures are similar to the skeletal muscle isoform SERCA1a pointing to a conserved mechanism. We seek to explain the kinetic differences between SERCA1a and SERCA2a. We find that several isoform-specific residues are acceptor sites for post-translational modifications. In addition, molecular dynamics simulations predict that isoform-specific residues support distinct intramolecular interactions in SERCA2a and SERCA1a. Our experimental observations further indicate that isoform-specific intramolecular interactions are functionally relevant, and may explain the kinetic differences between SERCA2a and SERCA1a.
Collapse
Affiliation(s)
- Aljona Sitsel
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark.,Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus C, Denmark
| | | | - Nikolaj Düring Drachmann
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark
| | - Rita Derua
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.,SyBioMa, KU Leuven, Leuven, Belgium
| | - Susanne Smaardijk
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Jacob Lauwring Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark.,Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | | | - Jialin Chen
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | | | - Etienne Waelkens
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.,SyBioMa, KU Leuven, Leuven, Belgium
| | - Claus Olesen
- Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark .,Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Peter Vangheluwe
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Poul Nissen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark .,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark.,Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus C, Denmark
| |
Collapse
|
2
|
Das A, Rui H, Nakamoto R, Roux B. Conformational Transitions and Alternating-Access Mechanism in the Sarcoplasmic Reticulum Calcium Pump. J Mol Biol 2017; 429:647-666. [PMID: 28093226 PMCID: PMC5467534 DOI: 10.1016/j.jmb.2017.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/31/2016] [Accepted: 01/08/2017] [Indexed: 11/22/2022]
Abstract
Ion pumps are integral membrane proteins responsible for transporting ions against concentration gradients across biological membranes. Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), a member of the P-type ATPases family, transports two calcium ions per hydrolyzed ATP molecule via an "alternating-access" mechanism. High-resolution crystallographic structures provide invaluable insight on the structural mechanism of the ion pumping process. However, to understand the molecular details of how ATP hydrolysis is coupled to calcium transport, it is necessary to gain knowledge about the conformational transition pathways connecting the crystallographically resolved conformations. Large-scale transitions in SERCA occur at time-scales beyond the current reach of unbiased molecular dynamics simulations. Here, we overcome this challenge by employing the string method, which represents a transition pathway as a chainofstates linking two conformational endpoints. Using a multiscale methodology, we have determined all-atom transition pathways for three main conformational transitions responsible for the alternating-access mechanism. The present pathways provide a clear chronology and ordering of the key events underlying the active transport of calcium ions by SERCA. Important conclusions are that the conformational transition that leads to occlusion with bound ATP and calcium is highly concerted and cooperative, the phosphorylation of Asp351 causes areorganization of the cytoplasmic domains that subsequently drives the opening of the luminal gate, and thereclosing of luminal gate induces a shift in the cytoplasmic domains that subsequently enables the dephosphorylation of Asp351-P. Formation of transient residue-residue contacts along the conformational transitions predicted by the computations provide an experimental route to test the general validity of the computational pathways.
Collapse
Affiliation(s)
- Avisek Das
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57(th) Street, Chicago,IL 60637, USA
| | - Huan Rui
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57(th) Street, Chicago,IL 60637, USA
| | - Robert Nakamoto
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, PO Box 800886, 480Ray C. Hunt Drive, Charlottesville, VA 22908, USA
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57(th) Street, Chicago,IL 60637, USA.
| |
Collapse
|
3
|
Tauber P, Aichinger B, Christ C, Stindl J, Rhayem Y, Beuschlein F, Warth R, Bandulik S. Cellular Pathophysiology of an Adrenal Adenoma-Associated Mutant of the Plasma Membrane Ca(2+)-ATPase ATP2B3. Endocrinology 2016; 157:2489-99. [PMID: 27035656 DOI: 10.1210/en.2015-2029] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adrenal aldosterone-producing adenomas (APAs) are a main cause for primary aldosteronism leading to arterial hypertension. Physiologically, aldosterone production in the adrenal gland is stimulated by angiotensin II and high extracellular potassium. These stimuli lead to a depolarization of the plasma membrane and, as a consequence, an increase of intracellular Ca(2+). Mutations of the plasma membrane Ca(2+)-ATPase ATP2B3 have been found in APAs with a prevalence of 0.6%-3.1%. Here, we investigated the effects of the APA-associated ATP2B3(Leu425_Val426del) mutation in adrenocortical NCI-H295R and human embryonic kidney (HEK-293) cells. Ca(2+) measurements revealed a higher basal Ca(2+) level in cells expressing the mutant ATP2B3. This rise in intracellular Ca(2+) was even more pronounced under conditions with high extracellular Ca(2+) pointing to an increased Ca(2+) influx associated with the mutated protein. Furthermore, cells with the mutant ATP2B3 appeared to have a reduced capacity to export Ca(2+) suggesting a loss of the physiological pump function. Surprisingly, expression of the mutant ATP2B3 caused a Na(+)-dependent inward current that strongly depolarized the plasma membrane and compromised the cytosolic cation composition. In parallel to these findings, mRNA expression of the cytochrome P450, family 11, subfamily B, polypeptide 2 (aldosterone synthase) was substantially increased and aldosterone production was enhanced in cells overexpressing mutant ATP2B3. In summary, the APA-associated ATP2B3(Leu425_Val426del) mutant promotes aldosterone production by at least 2 different mechanisms: 1) a reduced Ca(2+) export due to the loss of the physiological pump function; and 2) an increased Ca(2+) influx due to opening of depolarization-activated Ca(2+) channels as well as a possible Ca(2+) leak through the mutated pump.
Collapse
Affiliation(s)
- Philipp Tauber
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - B Aichinger
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - C Christ
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - J Stindl
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - Y Rhayem
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - F Beuschlein
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - R Warth
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - S Bandulik
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| |
Collapse
|
4
|
Daiho T, Yamasaki K, Danko S, Suzuki H. Second transmembrane helix (M2) and long range coupling in Ca²⁺-ATPase. J Biol Chem 2014; 289:31241-52. [PMID: 25246522 DOI: 10.1074/jbc.m114.584086] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The actuator (A) domain of sarco(endo)plasmic reticulum Ca(2+)-ATPase not only plays a catalytic role but also undergoes large rotational movements that influence the distant transport sites through connections with transmembrane helices M1 and M2. Here we explore the importance of long helix M2 and its junction with the A domain by disrupting the helix structure and elongating with insertions of five glycine residues. Insertions into the membrane region of M2 and the top junctional segment impair Ca(2+) transport despite reasonable ATPase activity, indicating that they are uncoupled. These mutants fail to occlude Ca(2+). Those at the top segment also exhibited accelerated phosphoenzyme isomerization E1P → E2P. Insertions into the middle of M2 markedly accelerate E2P hydrolysis and cause strong resistance to inhibition by luminal Ca(2+). Insertions along almost the entire M2 region inhibit the dephosphorylated enzyme transition E2 → E1. The results pinpoint which parts of M2 control cytoplasm gating and which are critical for luminal gating at each stage in the transport cycle and suggest that proper gate function requires appropriate interactions, tension, and/or rigidity in the M2 region at appropriate times for coupling with A domain movements and catalysis.
Collapse
Affiliation(s)
- Takashi Daiho
- From the Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| | - Kazuo Yamasaki
- From the Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| | - Stefania Danko
- From the Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| | - Hiroshi Suzuki
- From the Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| |
Collapse
|