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Steczina S, Mohran S, Bailey LRJ, McMillen TS, Kooiker KB, Wood NB, Davis J, Previs MJ, Olivotto I, Pioner JM, Geeves MA, Poggesi C, Regnier M. MYBPC3-c.772G>A mutation results in haploinsufficiency and altered myosin cycling kinetics in a patient induced stem cell derived cardiomyocyte model of hypertrophic cardiomyopathy. J Mol Cell Cardiol 2024; 191:27-39. [PMID: 38648963 DOI: 10.1016/j.yjmcc.2024.04.010] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 03/13/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Abstract
Approximately 40% of hypertrophic cardiomyopathy (HCM) mutations are linked to the sarcomere protein cardiac myosin binding protein-C (cMyBP-C). These mutations are either classified as missense mutations or truncation mutations. One mutation whose nature has been inconsistently reported in the literature is the MYBPC3-c.772G > A mutation. Using patient-derived human induced pluripotent stem cells differentiated to cardiomyocytes (hiPSC-CMs), we have performed a mechanistic study of the structure-function relationship for this MYBPC3-c.772G > A mutation versus a mutation corrected, isogenic cell line. Our results confirm that this mutation leads to exon skipping and mRNA truncation that ultimately suggests ∼20% less cMyBP-C protein (i.e., haploinsufficiency). This, in turn, results in increased myosin recruitment and accelerated myofibril cycling kinetics. Our mechanistic studies suggest that faster ADP release from myosin is a primary cause of accelerated myofibril cross-bridge cycling due to this mutation. Additionally, the reduction in force generating heads expected from faster ADP release during isometric contractions is outweighed by a cMyBP-C phosphorylation mediated increase in myosin recruitment that leads to a net increase of myofibril force, primarily at submaximal calcium activations. These results match well with our previous report on contractile properties from myectomy samples of the patients from whom the hiPSC-CMs were generated, demonstrating that these cell lines are a good model to study this pathological mutation and extends our understanding of the mechanisms of altered contractile properties of this HCM MYBPC3-c.772G > A mutation.
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Affiliation(s)
- Sonette Steczina
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Saffie Mohran
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Logan R J Bailey
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Molecular and Cellular Biology, University of Washington, Seattle, WA 98109, USA; Department of Lab Medicine and Pathology, University of Washington, Seattle, WA 98109, USA
| | - Timothy S McMillen
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA
| | - Kristina B Kooiker
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Neil B Wood
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05404, USA
| | - Jennifer Davis
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Department of Lab Medicine and Pathology, University of Washington, Seattle, WA 98109, USA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05404, USA
| | - Iacopo Olivotto
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Italy
| | | | | | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Italy
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA.
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Kelly CM, Martin JL, Previs MJ. Myosin folding boosts solubility in cardiac muscle sarcomeres. JCI Insight 2024; 9:e178131. [PMID: 38483507 DOI: 10.1172/jci.insight.178131] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/05/2024] [Indexed: 04/23/2024] Open
Abstract
The polymerization of myosin molecules into thick filaments in muscle sarcomeres is essential for cardiac contractility, with the attenuation of interactions between the heads of myosin molecules within the filaments being proposed to result in hypercontractility, as observed in hypertrophic cardiomyopathy (HCM). However, experimental evidence demonstrates that the structure of these giant macromolecular complexes is highly dynamic, with molecules exchanging between the filaments and a pool of soluble molecules on the minute timescale. Therefore, we sought to test the hypothesis that the enhancement of interactions between the heads of myosin molecules within thick filaments limits the mobility of myosin by taking advantage of mavacamten, a small molecule approved for the treatment of HCM. Myosin molecules were labeled in vivo with a green fluorescent protein (GFP) and imaged in intact hearts using multiphoton microscopy. Treatment of the intact hearts with mavacamten resulted in an unexpected > 5-fold enhancement in GFP-myosin mobility within the sarcomere. In vitro biochemical assays suggested that mavacamten enhanced the mobility of GFP-myosin by increasing the solubility of myosin molecules, through the stabilization of a compact/folded conformation of the molecules, once disassociated from the thick filaments. These findings provide alternative insight into the mechanisms by which molecules exchange into and out of thick filaments and have implications for how mavacamten may affect cardiac contractility.
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Affiliation(s)
- Colleen M Kelly
- Molecular Physiology and Biophysics Department, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Jody L Martin
- Department of Pharmacology, University of California, Davis, Davis, California, USA
| | - Michael J Previs
- Molecular Physiology and Biophysics Department, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
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Barefield DY, Tonino P, Woulfe KC, Rahmanseresht S, O’Leary TS, Burnham HV, Wasserstrom JA, Kirk JA, Previs MJ, Granzier HL, McNally EM. Myosin-binding protein H-like regulates myosin-binding protein distribution and function in atrial cardiomyocytes. Proc Natl Acad Sci U S A 2023; 120:e2314920120. [PMID: 38091294 PMCID: PMC10741380 DOI: 10.1073/pnas.2314920120] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/25/2023] [Indexed: 12/18/2023] Open
Abstract
Mutations in atrial-enriched genes can cause a primary atrial myopathy that can contribute to overall cardiovascular dysfunction. MYBPHL encodes myosin-binding protein H-like (MyBP-HL), an atrial sarcomere protein that shares domain homology with the carboxy-terminus of cardiac myosin-binding protein-C (cMyBP-C). The function of MyBP-HL and the relationship between MyBP-HL and cMyBP-C is unknown. To decipher the roles of MyBP-HL, we used structured illumination microscopy, immuno-electron microscopy, and mass spectrometry to establish the localization and stoichiometry of MyBP-HL. We found levels of cMyBP-C, a major regulator of myosin function, were half as abundant compared to levels in the ventricle. In genetic mouse models, loss of MyBP-HL doubled cMyBP-C abundance in the atria, and loss of cMyBP-C doubled MyBP-HL abundance in the atria. Structured illumination microscopy showed that both proteins colocalize in the C-zone of the A-band, with MyBP-HL enriched closer to the M-line. Immuno-electron microscopy of mouse atria showed MyBP-HL strongly localized 161 nm from the M-line, consistent with localization to the third 43 nm repeat of myosin heads. Both cMyBP-C and MyBP-HL had less-defined sarcomere localization in the atria compared to ventricle, yet areas with the expected 43 nm repeat distance were observed for both proteins. Isometric force measurements taken from control and Mybphl null single atrial myofibrils revealed that loss of Mybphl accelerated the linear phase of relaxation. These findings support a mechanism where MyBP-HL regulates cMyBP-C abundance to alter the kinetics of sarcomere relaxation in atrial sarcomeres.
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Affiliation(s)
- David Y. Barefield
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Paola Tonino
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Kathleen C. Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO80045
| | - Sheema Rahmanseresht
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Thomas S. O’Leary
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Hope V. Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - J. Andrew Wasserstrom
- Department of Medicine and The Feinberg Cardiovascular and Renal Institute, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Jonathan A. Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Henk L. Granzier
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
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Adam I, Riebel K, Stål P, Wood N, Previs MJ, Elemans CPH. Daily vocal exercise is necessary for peak performance singing in a songbird. Nat Commun 2023; 14:7787. [PMID: 38086817 PMCID: PMC10716414 DOI: 10.1038/s41467-023-43592-6] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 11/13/2023] [Indexed: 12/18/2023] Open
Abstract
Vocal signals, including human speech and birdsong, are produced by complicated, precisely coordinated body movements, whose execution is fitness-determining in resource competition and mate choice. While the acquisition and maintenance of motor skills generally requires practice to develop and maintain both motor circuitry and muscle performance, it is unknown whether vocal muscles, like limb muscles, exhibit exercise-induced plasticity. Here, we show that juvenile and adult zebra finches (Taeniopygia castanotis) require daily vocal exercise to first gain and subsequently maintain peak vocal muscle performance. Experimentally preventing male birds from singing alters both vocal muscle physiology and vocal performance within days. Furthermore, we find females prefer song of vocally exercised males in choice experiments. Vocal output thus contains information on recent exercise status, and acts as an honest indicator of past exercise investment in songbirds, and possibly in all vocalising vertebrates.
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Affiliation(s)
- Iris Adam
- Department of Biology, University of Southern Denmark, Odense, Denmark.
| | - Katharina Riebel
- Institute of Biology, Animal Sciences & Health, Leiden University, Leiden, The Netherlands
| | - Per Stål
- Department of Integrative Medical Biology, Umea University, Umeå, Sweden
| | - Neil Wood
- Department of Molecular Physiology and Biophysics, Larner College of Medicine, University of Vermont, Burlington, NJ, USA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, Larner College of Medicine, University of Vermont, Burlington, NJ, USA
| | - Coen P H Elemans
- Department of Biology, University of Southern Denmark, Odense, Denmark.
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Kelly CM, Martin JL, Coseno M, Previs MJ. Visualization of cardiac thick filament dynamics in ex vivo heart preparations. J Mol Cell Cardiol 2023; 185:88-98. [PMID: 37923195 PMCID: PMC10959293 DOI: 10.1016/j.yjmcc.2023.10.013] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
RATIONALE Cardiac muscle cells are terminally differentiated after birth and must beat continually throughout one's lifetime. This mechanical process is driven by the sliding of actin-based thin filaments along myosin-based thick filaments, organized within sarcomeres. Despite costly energetic demand, the half-life of the proteins that comprise the cardiac thick filaments is ∼10 days, with individual molecules being replaced stochastically, by unknown mechanisms. OBJECTIVES To allow for the stochastic replacement of molecules, we hypothesized that the structure of thick filaments must be highly dynamic in vivo. METHODS AND RESULTS To test this hypothesis in adult mouse hearts, we replaced a fraction of the endogenous myosin regulatory light chain (RLC), a component of thick filaments, with GFP-labeled RLC by adeno-associated viral (AAV) transduction. The RLC-GFP was properly localized to the heads of the myosin molecules within thick filaments in ex vivo heart preparations and had no effect on heart size or actin filament siding in vitro. However, the localization of the RLC-GFP molecules was highly mobile, changing its position within the sarcomere on the minute timescale, when quantified by fluorescence recovery after photobleaching (FRAP) using multiphoton microscopy. Interestingly, RLC-GFP mobility was restricted to within the boundaries of single sarcomeres. When cardiomyocytes were lysed, the RLC-GFP remained strongly bound to myosin heavy chain, and the intact myosin molecules adopted a folded, compact configuration, when disassociated from the filaments at physiological ionic conditions. CONCLUSIONS These data demonstrate that the structure of the thick filament is highly dynamic in the intact heart, with a rate of molecular exchange into and out of thick filaments that is ∼1500 times faster than that required for the replacement of molecules through protein synthesis or degradation.
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Affiliation(s)
- Colleen M Kelly
- Molecular Physiology and Biophysics Department, University of Vermont, Larner College of Medicine, Burlington, VT 05405, United States of America
| | - Jody L Martin
- Department of Pharmacology, University of California, Davis, Davis, CA 90095, United States of America
| | - Molly Coseno
- Fluidic Analytics, The Paddocks Business Centre, Cambridge CB1 8DH, United Kingdom
| | - Michael J Previs
- Molecular Physiology and Biophysics Department, University of Vermont, Larner College of Medicine, Burlington, VT 05405, United States of America.
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Li J, Rahmani H, Yeganeh FA, Rastegarpouyani H, Taylor DW, Wood NB, Previs MJ, Iwamoto H, Taylor KA. Structure and Arrangement of Non-myosin Proteins in the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus by CryoEM. Microsc Microanal 2023; 29:917-919. [PMID: 37613770 DOI: 10.1093/micmic/ozad067.454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Jiawei Li
- Florida State University, Institute of Molecular Biophysics, Tallahassee, FL, USA
| | - Hamidreza Rahmani
- Florida State University, Institute of Molecular Biophysics, Tallahassee, FL, USA
| | | | | | - Dianne W Taylor
- Florida State University, Institute of Molecular Biophysics, Tallahassee, FL, USA
| | - Neil B Wood
- Department of Molecular Physiology & Biophysics, College of Medicine, University of Vermont, Burlington, VT, USA
| | - Michael J Previs
- Department of Molecular Physiology & Biophysics, College of Medicine, University of Vermont, Burlington, VT, USA
| | - Hiroyuki Iwamoto
- Scattering and Imaging Division, Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo, Japan
| | - Kenneth A Taylor
- Florida State University, Institute of Molecular Biophysics, Tallahassee, FL, USA
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7
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Adam I, Riebel K, St L P, Wood NB, Previs MJ, Elemans CPH. Peak performance singing requires daily vocal exercise in songbirds. bioRxiv 2023:2023.02.23.529633. [PMID: 36865130 PMCID: PMC9980080 DOI: 10.1101/2023.02.23.529633] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Vocal signals mediate much of human and non-human communication. Key performance traits - such as repertoire size, speed and accuracy of delivery - affect communication efficacy in fitness-decisive contexts such as mate choice and resource competition 1 . Specialized fast vocal muscles 2,3 are central to accurate sound production 4 , but it is unknown whether vocal, like limb muscles 5,6 , need exercise to gain and maintain peak performance 7,8 . Here, we show that for song development in juvenile songbirds, the closest analogue to human speech acquisition 9 , regular vocal muscle exercise is crucial to achieve adult peak muscle performance. Furthermore, adult vocal muscle performance reduces within two days of abolishing exercise, leading to downregulation of critical proteins transforming fast to slower muscle fibre types. Daily vocal exercise is thus required to both gain and maintain peak vocal muscle performance, and if absent changes vocal output. We show that conspecifics can detect these acoustic changes and females prefer the song of exercised males. Song thus contains information on recent exercise status of the sender. Daily investment in vocal exercise to maintain peak performance is an unrecognized cost of singing and could explain why many birds sing daily even under adverse conditions 10 . Because neural regulation of syringeal and laryngeal muscle plasticity is equivalent, vocal output may reflect recent exercise status in all vocalizing vertebrates.
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Kelly CM, Martin JL, Coseno M, Previs MJ. Mechanisms of cardiac myosin replacement. Biophys J 2023; 122:169a. [PMID: 36782795 DOI: 10.1016/j.bpj.2022.11.1063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Colleen M Kelly
- Molecular Physiology and Biophysics, University of Vermont College of Medicine, Burlington, VT, USA
| | - Jody L Martin
- Pharmacology, University of California Davis, Davis, CA, USA; Cardiovascular Research Institute, University of California Davis, Davis, CA, USA
| | | | - Michael J Previs
- Molecular Physiology and Biophysics, University of Vermont College of Medicine, Burlington, VT, USA
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Kelly CM, Previs MJ. Thick filament dynamics: A mechanism for protein replacement within the sarcomere. Biophys J 2023; 122:4a. [PMID: 36784581 DOI: 10.1016/j.bpj.2022.11.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Colleen M Kelly
- Department of Molecular Physiology and Biophysics, University of Vermont College of Medicine, Burlington, VT, USA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of Vermont College of Medicine, Burlington, VT, USA
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Mead AF, Wood NB, Nelson SR, Kennedy GG, Ploysangngam A, Ebert AM, Johnson AN, Gurnett CA, Previs MJ, Warshaw DM. Myosin binding protein h dominates the "c-zone" in ultrafast swimming muscles of developing zebrafish. Biophys J 2023; 122:28a. [PMID: 36783438 DOI: 10.1016/j.bpj.2022.11.374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Andrew F Mead
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Neil B Wood
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Shane R Nelson
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Guy G Kennedy
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Angela Ploysangngam
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | | | - Aaron N Johnson
- Developmental Biology, Washington University in St. Louis, St. Louis, MO, USA
| | | | - Michael J Previs
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - David M Warshaw
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
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Li J, Rahmani H, Abbasi Yeganeh F, Rastegarpouyani H, Taylor DW, Wood NB, Previs MJ, Iwamoto H, Taylor KA. Structure of the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus, at 6 Å Resolution. Int J Mol Sci 2022; 24:377. [PMID: 36613818 PMCID: PMC9820631 DOI: 10.3390/ijms24010377] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
Four insect orders have flight muscles that are both asynchronous and indirect; they are asynchronous in that the wingbeat frequency is decoupled from the frequency of nervous stimulation and indirect in that the muscles attach to the thoracic exoskeleton instead of directly to the wing. Flight muscle thick filaments from two orders, Hemiptera and Diptera, have been imaged at a subnanometer resolution, both of which revealed a myosin tail arrangement referred to as “curved molecular crystalline layers”. Here, we report a thick filament structure from the indirect flight muscles of a third insect order, Hymenoptera, the Asian bumble bee Bombus ignitus. The myosin tails are in general agreement with previous determinations from Lethocerus indicus and Drosophila melanogaster. The Skip 2 region has the same unusual structure as found in Lethocerus indicus thick filaments, an α-helix discontinuity is also seen at Skip 4, but the orientation of the Skip 1 region on the surface of the backbone is less angled with respect to the filament axis than in the other two species. The heads are disordered as in Drosophila, but we observe no non-myosin proteins on the backbone surface that might prohibit the ordering of myosin heads onto the thick filament backbone. There are strong structural similarities among the three species in their non-myosin proteins within the backbone that suggest how one previously unassigned density in Lethocerus might be assigned. Overall, the structure conforms to the previously observed pattern of high similarity in the myosin tail arrangement, but differences in the non-myosin proteins.
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Affiliation(s)
- Jiawei Li
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Hamidreza Rahmani
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Fatemeh Abbasi Yeganeh
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Hosna Rastegarpouyani
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Dianne W. Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
| | - Neil B. Wood
- Department of Molecular Physiology & Biophysics, University of Vermont, Larner College of Medicine, Burlington, VT 05405, USA
| | - Michael J. Previs
- Department of Molecular Physiology & Biophysics, University of Vermont, Larner College of Medicine, Burlington, VT 05405, USA
| | - Hiroyuki Iwamoto
- Scattering and Imaging Division, Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198, Japan
| | - Kenneth A. Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
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Previs MJ. Calcium activation through thick and thin? J Gen Physiol 2022; 155:213763. [PMID: 36525070 PMCID: PMC9764020 DOI: 10.1085/jgp.202213265] [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: 12/23/2022] Open
Abstract
A historical perspective of the super-relaxed (SRX) state, interacting heads motif (IHM), and impact of calcium on muscle contractility.
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Affiliation(s)
- Michael J. Previs
- Molecular Physiology and Biophysics Department, Larner College of Medicine, University of Vermont, Burlington, VT, USA,Correspondence to Michael J. Previs:
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13
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Wood NB, Kelly CM, O’Leary TS, Martin JL, Previs MJ. Cardiac Myosin Filaments are Maintained by Stochastic Protein Replacement. Mol Cell Proteomics 2022; 21:100274. [PMID: 35921914 PMCID: PMC9528119 DOI: 10.1016/j.mcpro.2022.100274] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 07/08/2022] [Accepted: 07/19/2022] [Indexed: 01/18/2023] Open
Abstract
Myosin and myosin-binding protein C are exquisitely organized into giant filamentous macromolecular complexes within cardiac muscle sarcomeres, yet these proteins must be continually replaced to maintain contractile fidelity. The overall hypothesis that myosin filament structure is dynamic and allows for the stochastic replacement of individual components was tested in vivo, using a combination of mass spectrometry- and fluorescence-based proteomic techniques. Adult mice were fed a diet that marked all newly synthesized proteins with a stable isotope-labeled amino acid. The abundance of unlabeled and labeled proteins was quantified by high-resolution mass spectrometry over an 8-week period. The rates of change in the abundance of these proteins were well described by analytical models in which protein synthesis defined stoichiometry and protein degradation was governed by the stochastic selection of individual molecules. To test whether the whole myosin filaments or the individual components were selected for replacement, cardiac muscle was chemically skinned to remove the cellular membrane and myosin filaments were solubilized with ionic solutions. The composition of the filamentous and soluble fractions was quantified by mass spectrometry, and filament depolymerization was visualized by real-time fluorescence microscopy. Myosin molecules were preferentially extracted from ends of the filaments in the presence of the ionic solutions, and there was only a slight bias in the abundance of unlabeled molecules toward the innermost region on the myosin filaments. These data demonstrate for the first time that the newly synthesized myosin and myosin-binding protein C molecules are randomly mixed into preexisting thick filaments in vivo and the rate of mixing may not be equivalent along the length of the thick filament. These data collectively support a new model of cardiac myosin filament structure, with the filaments being dynamic macromolecular assemblies that allow for replacement of their components, rather than rigid bodies.
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Affiliation(s)
- Neil B. Wood
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
| | - Colleen M. Kelly
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
| | - Thomas S. O’Leary
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
| | - Jody L. Martin
- Department of Pharmacology, University of California, Davis, Davis, California, USA
| | - Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA,For correspondence: Michael J. Previs, Department of Molecular Physiology & Biophysics, Larner College of Medicine, University of Vermont, Health Science Research Facility, 149 Beaumont Avenue, Room 108, Burlington, Vermont 05405
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14
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Previs MJ, O’Leary TS, Morley MP, Palmer B, LeWinter M, Yob J, Pagani FD, Petucci C, Kim MS, Margulies KB, Arany Z, Kelly DP, Day SM. Defects in the Proteome and Metabolome in Human Hypertrophic Cardiomyopathy. Circ Heart Fail 2022; 15:e009521. [PMID: 35543134 PMCID: PMC9708114 DOI: 10.1161/circheartfailure.121.009521] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Defects in energetics are thought to be central to the pathophysiology of hypertrophic cardiomyopathy (HCM); yet, the determinants of ATP availability are not known. The purpose of this study is to ascertain the nature and extent of metabolic reprogramming in human HCM, and its potential impact on contractile function. METHODS We conducted proteomic and targeted, quantitative metabolomic analyses on heart tissue from patients with HCM and from nonfailing control human hearts. RESULTS In the proteomic analysis, the greatest differences observed in HCM samples compared with controls were increased abundances of extracellular matrix and intermediate filament proteins and decreased abundances of muscle creatine kinase and mitochondrial proteins involved in fatty acid oxidation. These differences in protein abundance were coupled with marked reductions in acyl carnitines, byproducts of fatty acid oxidation, in HCM samples. Conversely, the ketone body 3-hydroxybutyrate, branched chain amino acids, and their breakdown products, were all significantly increased in HCM hearts. ATP content, phosphocreatine, nicotinamide adenine dinucleotide and its phosphate derivatives, NADP and NADPH, and acetyl CoA were also severely reduced in HCM compared with control hearts. Functional assays performed on human skinned myocardial fibers demonstrated that the magnitude of observed reduction in ATP content in the HCM samples would be expected to decrease the rate of cross-bridge detachment. Moreover, left atrial size, an indicator of diastolic compliance, was inversely correlated with ATP content in hearts from patients with HCM. CONCLUSIONS HCM hearts display profound deficits in nucleotide availability with markedly reduced capacity for fatty acid oxidation and increases in ketone bodies and branched chain amino acids. These results have important therapeutic implications for the future design of metabolic modulators to treat HCM.
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Affiliation(s)
- Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Thomas S. O’Leary
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Michael P. Morley
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Brad Palmer
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Martin LeWinter
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Jaime Yob
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Francis D. Pagani
- Department of Cardiothoracic Surgery, University of Michigan School of Medicine
| | - Christopher Petucci
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Min-Soo Kim
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Kenneth B. Margulies
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Zoltan Arany
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Daniel P. Kelly
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Sharlene M. Day
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
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15
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Rasicci DV, Ge J, Wood N, Milburn G, Previs MJ, Campbell KS, Yengo CM. Cardiac myosin mechanochemistry underlies left ventricular dysfunction in human ischemic heart failure. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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16
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Steczina S, Pioner JM, Langione M, Wood N, Vitale G, Tesi C, Coppini R, Ferrantini C, Previs MJ, Poggesi C, Regnier M. Mechanisms of dysfunction in patient-derived cardiomyocytes with the hypertrophic cardiomyopathy-myosin binding protein-C e258K mutation. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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17
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Riley LA, Zhang X, Douglas CM, Mijares JM, Hammers DW, Wolff CA, Wood NB, Olafson HR, Du P, Labeit S, Previs MJ, Wang ET, Esser KA. The skeletal muscle circadian clock regulates titin splicing through RBM20. eLife 2022; 11:76478. [PMID: 36047761 PMCID: PMC9473687 DOI: 10.7554/elife.76478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 12/17/2021] [Accepted: 08/31/2022] [Indexed: 02/01/2023] Open
Abstract
Circadian rhythms are maintained by a cell-autonomous, transcriptional-translational feedback loop known as the molecular clock. While previous research suggests a role of the molecular clock in regulating skeletal muscle structure and function, no mechanisms have connected the molecular clock to sarcomere filaments. Utilizing inducible, skeletal muscle specific, Bmal1 knockout (iMSBmal1-/-) mice, we showed that knocking out skeletal muscle clock function alters titin isoform expression using RNAseq, liquid chromatography-mass spectrometry, and sodium dodecyl sulfate-vertical agarose gel electrophoresis. This alteration in titin's spring length resulted in sarcomere length heterogeneity. We demonstrate the direct link between altered titin splicing and sarcomere length in vitro using U7 snRNPs that truncate the region of titin altered in iMSBmal1-/- muscle. We identified a mechanism whereby the skeletal muscle clock regulates titin isoform expression through transcriptional regulation of Rbm20, a potent splicing regulator of titin. Lastly, we used an environmental model of circadian rhythm disruption and identified significant downregulation of Rbm20 expression. Our findings demonstrate the importance of the skeletal muscle circadian clock in maintaining titin isoform through regulation of RBM20 expression. Because circadian rhythm disruption is a feature of many chronic diseases, our results highlight a novel pathway that could be targeted to maintain skeletal muscle structure and function in a range of pathologies.
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Affiliation(s)
- Lance A Riley
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Xiping Zhang
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Collin M Douglas
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Joseph M Mijares
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - David W Hammers
- Myology Institute, University of FloridaGainesvilleUnited States,Department of Pharmacology and Therapeutics, University of FloridaGainesvilleUnited States
| | - Christopher A Wolff
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Neil B Wood
- Department of Molecular Physiology and Biophysics, University of VermontBurlingtonUnited States
| | - Hailey R Olafson
- Department of Molecular Genetics of Microbiology, Center for Neurogenetics, University of FloridaGainesvilleUnited States
| | - Ping Du
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States
| | - Siegfried Labeit
- Medical Faculty Mannheim, University of HeidelbergMannheimGermany
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of VermontBurlingtonUnited States
| | - Eric T Wang
- Myology Institute, University of FloridaGainesvilleUnited States,Department of Molecular Genetics of Microbiology, Center for Neurogenetics, University of FloridaGainesvilleUnited States
| | - Karyn A Esser
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
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18
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Tsan YC, DePalma SJ, Zhao YT, Capilnasiu A, Wu YW, Elder B, Panse I, Ufford K, Matera DL, Friedline S, O'Leary TS, Wubshet N, Ho KKY, Previs MJ, Nordsletten D, Isom LL, Baker BM, Liu AP, Helms AS. Physiologic biomechanics enhance reproducible contractile development in a stem cell derived cardiac muscle platform. Nat Commun 2021; 12:6167. [PMID: 34697315 PMCID: PMC8546060 DOI: 10.1038/s41467-021-26496-1] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 10/05/2021] [Indexed: 12/29/2022] Open
Abstract
Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) allow investigations in a human cardiac model system, but disorganized mechanics and immaturity of hPSC-CMs on standard two-dimensional surfaces have been hurdles. Here, we developed a platform of micron-scale cardiac muscle bundles to control biomechanics in arrays of thousands of purified, independently contracting cardiac muscle strips on two-dimensional elastomer substrates with far greater throughput than single cell methods. By defining geometry and workload in this reductionist platform, we show that myofibrillar alignment and auxotonic contractions at physiologic workload drive maturation of contractile function, calcium handling, and electrophysiology. Using transcriptomics, reporter hPSC-CMs, and quantitative immunofluorescence, these cardiac muscle bundles can be used to parse orthogonal cues in early development, including contractile force, calcium load, and metabolic signals. Additionally, the resultant organized biomechanics facilitates automated extraction of contractile kinetics from brightfield microscopy imaging, increasing the accessibility, reproducibility, and throughput of pharmacologic testing and cardiomyopathy disease modeling. Investigations of human cardiac disease involving human pluripotent stem cell-derived cardiomyocytes are limited by the disorganized presentation of biomechanical cues resulting in cell immaturity. Here the authors develop a platform of micron-scale 2D cardiac muscle bundles to precisely deliver physiologic cues, improving reproducibility and throughput.
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Affiliation(s)
- Yao-Chang Tsan
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA.,Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Samuel J DePalma
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Yan-Ting Zhao
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Adela Capilnasiu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Yu-Wei Wu
- Institute of Molecular Biology, Academia Sinica, NanKang, Taipei, Taiwan
| | - Brynn Elder
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Isabella Panse
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Kathryn Ufford
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Daniel L Matera
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Sabrina Friedline
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Thomas S O'Leary
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Nadab Wubshet
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Kenneth K Y Ho
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Michael J Previs
- Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - David Nordsletten
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Department of Cardiovascular Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA.,Department of Neurology, University of Michigan, Ann Arbor, MI, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Brendon M Baker
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Allen P Liu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.,Department of Biophysics, University of Michigan, Ann Arbor, MI, USA
| | - Adam S Helms
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA.
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19
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Tanner BCW, Previs MJ, Wang Y, Robbins J, Palmer BM. Cardiac myosin binding protein-C phosphorylation accelerates β-cardiac myosin detachment rate in mouse myocardium. Am J Physiol Heart Circ Physiol 2021; 320:H1822-H1835. [PMID: 33666504 PMCID: PMC8163640 DOI: 10.1152/ajpheart.00673.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 02/08/2021] [Accepted: 03/01/2021] [Indexed: 11/22/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) is a thick filament protein that influences sarcomere stiffness and modulates cardiac contraction-relaxation through its phosphorylation. Phosphorylation of cMyBP-C and ablation of cMyBP-C have been shown to increase the rate of MgADP release in the acto-myosin cross-bridge cycle in the intact sarcomere. The influence of cMyBP-C on Pi-dependent myosin kinetics has not yet been examined. We investigated the effect of cMyBP-C, and its phosphorylation, on myosin kinetics in demembranated papillary muscle strips bearing the β-cardiac myosin isoform from nontransgenic and homozygous transgenic mice lacking cMyBP-C. We used quick stretch and stochastic length-perturbation analysis to characterize rates of myosin detachment and force development over 0-12 mM Pi and at maximal (pCa 4.8) and near-half maximal (pCa 5.75) Ca2+ activation. Protein kinase A (PKA) treatment was applied to half the strips to probe the effect of cMyBP-C phosphorylation on Pi sensitivity of myosin kinetics. Increasing Pi increased myosin cross-bridge detachment rate similarly for muscles with and without cMyBP-C, although these rates were higher in muscle without cMyBP-C. Treating myocardial strips with PKA accelerated detachment rate when cMyBP-C was present over all Pi, but not when cMyBP-C was absent. The rate of force development increased with Pi in all muscles. However, Pi sensitivity of the rate force development was reduced when cMyBP-C was present versus absent, suggesting that cMyBP-C inhibits Pi-dependent reversal of the power stroke or stabilizes cross-bridge attachment to enhance the probability of completing the power stroke. These results support a functional role for cMyBP-C in slowing myosin detachment rate, possibly through a direct interaction with myosin or by altering strain-dependent myosin detachment via cMyBP-C-dependent stiffness of the thick filament and myofilament lattice. PKA treatment reduces the role for cMyBP-C to slow myosin detachment and thus effectively accelerates β-myosin detachment in the intact myofilament lattice.NEW & NOTEWORTHY Length perturbation analysis was used to demonstrate that β-cardiac myosin characteristic rates of detachment and recruitment in the intact myofilament lattice are accelerated by Pi, phosphorylation of cMyBP-C, and the absence of cMyBP-C. The results suggest that cMyBP-C normally slows myosin detachment, including Pi-dependent detachment, and that this inhibition is released with phosphorylation or absence of cMyBP-C.
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Affiliation(s)
- Bertrand C W Tanner
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont
| | - Yuan Wang
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont
| | - Jeffrey Robbins
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Bradley M Palmer
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont
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20
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Rasicci DV, Kirkland O, Moonschi FH, Wood NB, Szczesna-Cordary D, Previs MJ, Wenk JF, Campbell KS, Yengo CM. Impact of regulatory light chain mutation K104E on the ATPase and motor properties of cardiac myosin. J Gen Physiol 2021; 153:212025. [PMID: 33891674 PMCID: PMC8077168 DOI: 10.1085/jgp.202012811] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/19/2021] [Indexed: 12/11/2022] Open
Abstract
Mutations in the cardiac myosin regulatory light chain (RLC, MYL2 gene) are known to cause inherited cardiomyopathies with variable phenotypes. In this study, we investigated the impact of a mutation in the RLC (K104E) that is associated with hypertrophic cardiomyopathy (HCM). Previously in a mouse model of K104E, older animals were found to develop cardiac hypertrophy, fibrosis, and diastolic dysfunction, suggesting a slow development of HCM. However, variable penetrance of the mutation in human populations suggests that the impact of K104E may be subtle. Therefore, we generated human cardiac myosin subfragment-1 (M2β-S1) and exchanged on either the wild type (WT) or K104E human ventricular RLC in order to assess the impact of the mutation on the mechanochemical properties of cardiac myosin. The maximum actin-activated ATPase activity and actin sliding velocities in the in vitro motility assay were similar in M2β-S1 WT and K104E, as were the detachment kinetic parameters, including the rate of ATP-induced dissociation and the ADP release rate constant. We also examined the mechanical performance of α-cardiac myosin extracted from transgenic (Tg) mice expressing human wild type RLC (Tg WT) or mutant RLC (Tg K104E). We found that α-cardiac myosin from Tg K104E animals demonstrated enhanced actin sliding velocities in the motility assay compared with its Tg WT counterpart. Furthermore, the degree of incorporation of the mutant RLC into α-cardiac myosin in the transgenic animals was significantly reduced compared with wild type. Therefore, we conclude that the impact of the K104E mutation depends on either the length or the isoform of the myosin heavy chain backbone and that the mutation may disrupt RLC interactions with the myosin lever arm domain.
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Affiliation(s)
- David V Rasicci
- Pennsylvania State University College of Medicine, Hershey, PA
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21
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Arnold ME, Dostmann WR, Martin J, Previs MJ, Palmer B, LeWinter M, Meyer M. SERCA2a-phospholamban interaction monitored by an interposed circularly permutated green fluorescent protein. Am J Physiol Heart Circ Physiol 2021; 320:H2188-H2200. [PMID: 33861144 DOI: 10.1152/ajpheart.00858.2020] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interaction of phospholamban (PLB) and the sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) is a key regulator of cardiac contractility and a therapeutic target in heart failure (HF). PLB-mediated increases in SERCA2a activity improve cardiac function and HF. Clinically, this mechanism can only be exploited by a general activation of the proteinkinase A (PKA), which is associated with side effects and adverse clinical outcomes. A selective interference of the PLB-SERCA2a interaction is desirable but will require novel tools that allow for an integrated assessment of this interaction under both physiological and pathophysiological conditions. A circularly permutated green fluorescent protein (cpGFP) was interposed between SERCA2a and PLB to result into a single SERCA2a-cpGFP-PLB recombinant protein (SGP). Expression, phosphorylation, fluorescence, and function of SGP were evaluated. Expression of SGP-cDNA results in a functional recombinant protein at the predicted molecular weight. The PLB domain of SGP retains its ability to polymerize and can be phosphorylated by PKA activation. This increases the fluorescent yield of SGP by between 10% and 165% depending on cell line and conditions. In conclusion, a single recombinant fusion protein that combines SERCA2a, a circularly permutated green fluorescent protein, and PLB can be expressed in cells and can be phosphorylated at the PLB domain that markedly increases the fluorescence yield. SGP is a novel cellular SERCA2a-PLB interaction monitor.NEW & NOTEWORTHY This study describes the design and characterization of a novel biosensor that can visualize the interaction of SERCA2a and phospholamban (PLB). The biosensor combines SERCA2a, a circularly permutated green fluorescent protein, and PLB into one recombinant protein (SGP). Proteinkinase A activation results in phosphorylation of the PLB domain and is associated with a marked increase in the fluorescence yield to allow for real-time monitoring of the SERCA2a and PLB interaction in cells.
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Affiliation(s)
- Maren E Arnold
- Department of Medicine and Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, Vermont.,Institute of Experimental and Clinical Pharmacology und Toxicology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Wolfgang R Dostmann
- Department of Pharmacology, University of Vermont Larner College of Medicine, Burlington, Vermont
| | - Jody Martin
- Department of Pharmacology, School of Medicine, Cardiovascular Research Institute, University of California, Davis, California
| | - Michael J Previs
- Department of Medicine and Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, Vermont
| | - Bradley Palmer
- Department of Medicine and Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, Vermont
| | - Martin LeWinter
- Department of Medicine and Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, Vermont
| | - Markus Meyer
- Department of Medicine, Lillehei Heart Institute, University of Minnesota College of Medicine, Minneapolis, Minnesota
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22
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Lynch TL, Kumar M, McNamara JW, Kuster DWD, Sivaguru M, Singh RR, Previs MJ, Lee KH, Kuffel G, Zilliox MJ, Lin BL, Ma W, Gibson AM, Blaxall BC, Nieman ML, Lorenz JN, Leichter DM, Leary OP, Janssen PML, de Tombe PP, Gilbert RJ, Craig R, Irving T, Warshaw DM, Sadayappan S. Amino terminus of cardiac myosin binding protein-C regulates cardiac contractility. J Mol Cell Cardiol 2021; 156:33-44. [PMID: 33781820 DOI: 10.1016/j.yjmcc.2021.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 12/12/2022]
Abstract
Phosphorylation of cardiac myosin binding protein-C (cMyBP-C) regulates cardiac contraction through modulation of actomyosin interactions mediated by the protein's amino terminal (N')-region (C0-C2 domains, 358 amino acids). On the other hand, dephosphorylation of cMyBP-C during myocardial injury results in cleavage of the 271 amino acid C0-C1f region and subsequent contractile dysfunction. Yet, our current understanding of amino terminus region of cMyBP-C in the context of regulating thin and thick filament interactions is limited. A novel cardiac-specific transgenic mouse model expressing cMyBP-C, but lacking its C0-C1f region (cMyBP-C∆C0-C1f), displayed dilated cardiomyopathy, underscoring the importance of the N'-region in cMyBP-C. Further exploring the molecular basis for this cardiomyopathy, in vitro studies revealed increased interfilament lattice spacing and rate of tension redevelopment, as well as faster actin-filament sliding velocity within the C-zone of the transgenic sarcomere. Moreover, phosphorylation of the unablated phosphoregulatory sites was increased, likely contributing to normal sarcomere morphology and myoarchitecture. These results led us to hypothesize that restoration of the N'-region of cMyBP-C would return actomyosin interaction to its steady state. Accordingly, we administered recombinant C0-C2 (rC0-C2) to permeabilized cardiomyocytes from transgenic, cMyBP-C null, and human heart failure biopsies, and we found that normal regulation of actomyosin interaction and contractility was restored. Overall, these data provide a unique picture of selective perturbations of the cardiac sarcomere that either lead to injury or adaptation to injury in the myocardium.
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Affiliation(s)
- Thomas L Lynch
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL 60153, USA
| | - Mohit Kumar
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL 60153, USA; Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - James W McNamara
- Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Diederik W D Kuster
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL 60153, USA; Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Mayandi Sivaguru
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Rohit R Singh
- Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT 05405, USA
| | - Kyoung Hwan Lee
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Gina Kuffel
- Department of Public Health Sciences, Loyola University Chicago, Maywood, IL 60153, USA
| | - Michael J Zilliox
- Department of Public Health Sciences, Loyola University Chicago, Maywood, IL 60153, USA
| | - Brian Leei Lin
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL 60153, USA
| | - Weikang Ma
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Aaron M Gibson
- Department of Pediatrics, Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Burns C Blaxall
- Department of Pediatrics, Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Michelle L Nieman
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - John N Lorenz
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Dana M Leichter
- Research Service, Providence VA Medical Center, Providence, RI 02908, USA
| | - Owen P Leary
- Research Service, Providence VA Medical Center, Providence, RI 02908, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Pieter P de Tombe
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL 60153, USA; Department of Physiology, University of Illinois at Chicago, Chicago 60612, USA; Phymedexp, Université de Montpellier, Inserm, CNRS, Montpellier, France
| | - Richard J Gilbert
- Research Service, Providence VA Medical Center, Providence, RI 02908, USA
| | - Roger Craig
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Thomas Irving
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - David M Warshaw
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT 05405, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL 60153, USA; Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.
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23
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Cario A, Wood NB, Liu Z, Hendricks AG, Previs MJ, Berger CL. Novel Effect of Tau N-Terminal Mutation, R5L, on Microtubule Mediated Condensation. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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24
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Rahmanseresht S, Lee KH, O'Leary TS, McNamara JW, Sadayappan S, Robbins J, Warshaw DM, Craig R, Previs MJ. The N terminus of myosin-binding protein C extends toward actin filaments in intact cardiac muscle. J Gen Physiol 2021; 153:211744. [PMID: 33528507 PMCID: PMC7852460 DOI: 10.1085/jgp.202012726] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/23/2020] [Accepted: 12/03/2020] [Indexed: 12/31/2022] Open
Abstract
Myosin and actin filaments are highly organized within muscle sarcomeres. Myosin-binding protein C (MyBP-C) is a flexible, rod-like protein located within the C-zone of the sarcomere. The C-terminal domain of MyBP-C is tethered to the myosin filament backbone, and the N-terminal domains are postulated to interact with actin and/or the myosin head to modulate filament sliding. To define where the N-terminal domains of MyBP-C are localized in the sarcomere of active and relaxed mouse myocardium, the relative positions of the N terminus of MyBP-C and actin were imaged in fixed muscle samples using super-resolution fluorescence microscopy. The resolution of the imaging was enhanced by particle averaging. The images demonstrate that the position of the N terminus of MyBP-C is biased toward the actin filaments in both active and relaxed muscle preparations. Comparison of the experimental images with images generated in silico, accounting for known binding partner interactions, suggests that the N-terminal domains of MyBP-C may bind to actin and possibly the myosin head but only when the myosin head is in the proximity of an actin filament. These physiologically relevant images help define the molecular mechanism by which the N-terminal domains of MyBP-C may search for, and capture, molecular binding partners to tune cardiac contractility.
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Affiliation(s)
- Sheema Rahmanseresht
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT
| | - Kyoung H Lee
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Thomas S O'Leary
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT
| | - James W McNamara
- Heart, Lung and Vascular Institute, Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH
| | - Sakthivel Sadayappan
- Heart, Lung and Vascular Institute, Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH
| | - Jeffrey Robbins
- Department of Pediatrics and the Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - David M Warshaw
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT
| | - Roger Craig
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT
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25
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Downes DP, Kasumov T, Daurio NA, Wood NB, Previs MJ, Sheth PR, McLaren DG, Previs SF. Isotope Fractionation during Gas Chromatography Can Enhance Mass Spectrometry-Based Measures of 2H-Labeling of Small Molecules. Metabolites 2020; 10:E474. [PMID: 33233825 PMCID: PMC7699861 DOI: 10.3390/metabo10110474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 09/16/2020] [Revised: 11/06/2020] [Accepted: 11/12/2020] [Indexed: 11/16/2022] Open
Abstract
Stable isotope tracers can be used to quantify the activity of metabolic pathways. Specifically, 2H-water is quite versatile, and its incorporation into various products can enable measurements of carbohydrate, lipid, protein and nucleic acid kinetics. However, since there are limits on how much 2H-water can be administered and since some metabolic processes may be slow, it is possible that one may be challenged with measuring small changes in isotopic enrichment. We demonstrate an advantage of the isotope fractionation that occurs during gas chromatography, namely, setting tightly bounded integration regions yields a powerful approach for determining isotope ratios. We determined how the degree of isotope fractionation, chromatographic peak width and mass spectrometer dwell time can increase the apparent isotope labeling. Relatively simple changes in the logic surrounding data acquisition and processing can enhance gas chromatography-mass spectrometry measures of low levels of 2H-labeling, this is especially useful when asymmetrical peaks are recorded at low signal:background. Although we have largely focused attention on alanine (which is of interest in studies of protein synthesis), it should be possible to extend the concepts to other analytes and/or hardware configurations.
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Affiliation(s)
- Daniel P. Downes
- Department of Chemistry, Merck & Co., Inc., Kenilworth, NJ 07033, USA; (D.P.D.); (N.A.D.); (P.R.S.); (D.G.M.)
| | - Takhar Kasumov
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA;
| | - Natalie A. Daurio
- Department of Chemistry, Merck & Co., Inc., Kenilworth, NJ 07033, USA; (D.P.D.); (N.A.D.); (P.R.S.); (D.G.M.)
| | - Neil B. Wood
- Department of Molecular Physiology & Biophysics, University of Vermont, Burlington, VT 05405, USA; (N.B.W.); (M.J.P.)
| | - Michael J. Previs
- Department of Molecular Physiology & Biophysics, University of Vermont, Burlington, VT 05405, USA; (N.B.W.); (M.J.P.)
| | - Payal R. Sheth
- Department of Chemistry, Merck & Co., Inc., Kenilworth, NJ 07033, USA; (D.P.D.); (N.A.D.); (P.R.S.); (D.G.M.)
| | - David G. McLaren
- Department of Chemistry, Merck & Co., Inc., Kenilworth, NJ 07033, USA; (D.P.D.); (N.A.D.); (P.R.S.); (D.G.M.)
| | - Stephen F. Previs
- Department of Chemistry, Merck & Co., Inc., Kenilworth, NJ 07033, USA; (D.P.D.); (N.A.D.); (P.R.S.); (D.G.M.)
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Daurio NA, Zhou H, Chen Y, Sheth PR, Imbriglio JE, McLaren DG, Tawa P, Rachdaoui N, Previs MJ, Kasumov T, O’Neil J, Previs SF. Examining Targeted Protein Degradation from Physiological and Analytical Perspectives: Enabling Translation between Cells and Subjects. ACS Chem Biol 2020; 15:2623-2635. [PMID: 32930572 DOI: 10.1021/acschembio.0c00380] [Citation(s) in RCA: 5] [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: 12/17/2022]
Abstract
The ability to target specific proteins for degradation may open a new door toward developing therapeutics. Although effort in chemistry is essential for advancing this modality, i.e., one needs to generate proteolysis targeting chimeras (bifunctional molecules, also referred to as PROTACS) or "molecular glues" to accelerate protein degradation, we suspect that investigations could also benefit by directing attention toward physiological regulation surrounding protein homeostasis, including the methods that can be used to examine changes in protein kinetics. This perspective will first consider some metabolic scenarios that might be of importance when one aims to change protein abundance by increasing protein degradation. Specifically, could protein turnover impact the apparent outcome? We will then outline how to study protein dynamics by coupling stable isotope tracer methods with mass spectrometry-based detection; since the experimental conditions could have a dramatic effect on protein turnover, special attention is directed toward the application of methods for quantifying protein kinetics using in vitro and in vivo models. Our goal is to present key concepts that should enable mechanistically informed studies which test targeted protein degradation strategies.
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Affiliation(s)
- Natalie A. Daurio
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - Haihong Zhou
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - Ying Chen
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - Payal R. Sheth
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - Jason E. Imbriglio
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - David G. McLaren
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - Paul Tawa
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - Nadia Rachdaoui
- Department of Animal Sciences, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08901, United States
| | - Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05454, United States
| | - Takhar Kasumov
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio 44272, United States
| | - Jennifer O’Neil
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
| | - Stephen F. Previs
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, United States
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Ste Marie EJ, Wehrle RJ, Haupt DJ, Wood NB, van der Vliet A, Previs MJ, Masterson DS, Hondal RJ. Can Selenoenzymes Resist Electrophilic Modification? Evidence from Thioredoxin Reductase and a Mutant Containing α-Methylselenocysteine. Biochemistry 2020; 59:3300-3315. [PMID: 32845139 DOI: 10.1021/acs.biochem.0c00608] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Selenocysteine (Sec) is the 21st proteogenic amino acid in the genetic code. Incorporation of Sec into proteins is a complex and bioenergetically costly process that evokes the following question: "Why did nature choose selenium?" An answer that has emerged over the past decade is that Sec confers resistance to irreversible oxidative inactivation by reactive oxygen species. Here, we explore the question of whether this concept can be broadened to include resistance to reactive electrophilic species (RES) because oxygen and related compounds are merely a subset of RES. To test this hypothesis, we inactivated mammalian thioredoxin reductase (Sec-TrxR), a mutant containing α-methylselenocysteine [(αMe)Sec-TrxR], and a cysteine ortholog TrxR (Cys-TrxR) with various electrophiles, including acrolein, 4-hydroxynonenal, and curcumin. Our results show that the acrolein-inactivated Sec-TrxR and the (αMe)Sec-TrxR mutant could regain 25% and 30% activity, respectively, when incubated with 2 mM H2O2 and 5 mM imidazole. In contrast, Cys-TrxR did not regain activity under the same conditions. We posit that Sec enzymes can undergo a repair process via β-syn selenoxide elimination that ejects the electrophile, leaving the enzyme in the oxidized selenosulfide state. (αMe)Sec-TrxR was created by incorporating the non-natural amino acid (αMe)Sec into TrxR by semisynthesis and allowed for rigorous testing of our hypothesis. This Sec derivative enables higher resistance to both oxidative and electrophilic inactivation because it lacks a backbone Cα-H, which prevents loss of selenium through the formation of dehydroalanine. This is the first time this unique amino acid has been incorporated into an enzyme and is an example of state-of-the-art protein engineering.
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Affiliation(s)
- Emma J Ste Marie
- Department of Biochemistry, University of Vermont, 89 Beaumont Avenue, Burlington, Vermont 05405, United States.,Department of Chemistry, Discovery Hall, University of Vermont, 82 University Place, Burlington, Vermont 05405, United States
| | - Robert J Wehrle
- School of Mathematics and Natural Sciences, Chemistry and Biochemistry, University of Southern Mississippi, 118 College Drive, Hattiesburg, Mississippi 39406, United States
| | - Daniel J Haupt
- Department of Chemistry, Discovery Hall, University of Vermont, 82 University Place, Burlington, Vermont 05405, United States
| | - Neil B Wood
- Department of Molecular Physiology & Biophysics, University of Vermont, 89 Beaumont Avenue, Burlington, Vermont 05405, United States
| | - Albert van der Vliet
- Department of Pathology and Laboratory Medicine, University of Vermont, 149 Beaumont Avenue, Burlington, Vermont 05405, United States
| | - Michael J Previs
- Department of Molecular Physiology & Biophysics, University of Vermont, 89 Beaumont Avenue, Burlington, Vermont 05405, United States
| | - Douglas S Masterson
- School of Mathematics and Natural Sciences, Chemistry and Biochemistry, University of Southern Mississippi, 118 College Drive, Hattiesburg, Mississippi 39406, United States
| | - Robert J Hondal
- Department of Biochemistry, University of Vermont, 89 Beaumont Avenue, Burlington, Vermont 05405, United States.,Department of Chemistry, Discovery Hall, University of Vermont, 82 University Place, Burlington, Vermont 05405, United States
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Daneshparvar N, Taylor DW, O'Leary TS, Rahmani H, Abbasiyeganeh F, Previs MJ, Taylor KA. CryoEM structure of Drosophila flight muscle thick filaments at 7 Å resolution. Life Sci Alliance 2020; 3:3/8/e202000823. [PMID: 32718994 PMCID: PMC7391215 DOI: 10.26508/lsa.202000823] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 11/24/2022] Open
Abstract
Striated muscle thick filaments are composed of myosin II and several non-myosin proteins. Myosin II's long α-helical coiled-coil tail forms the dense protein backbone of filaments, whereas its N-terminal globular head containing the catalytic and actin-binding activities extends outward from the backbone. Here, we report the structure of thick filaments of the flight muscle of the fruit fly Drosophila melanogaster at 7 Å resolution. Its myosin tails are arranged in curved molecular crystalline layers identical to flight muscles of the giant water bug Lethocerus indicus Four non-myosin densities are observed, three of which correspond to ones found in Lethocerus; one new density, possibly stretchin-mlck, is found on the backbone outer surface. Surprisingly, the myosin heads are disordered rather than ordered along the filament backbone. Our results show striking myosin tail similarity within flight muscle filaments of two insect orders separated by several hundred million years of evolution.
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Affiliation(s)
- Nadia Daneshparvar
- Department of Physics, Florida State University, Tallahassee, FL, USA.,Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, USA
| | - Dianne W Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, USA
| | - Thomas S O'Leary
- Department of Molecular Physiology & Biophysics, University of Vermont College of Medicine, Burlington, VT, USA
| | - Hamidreza Rahmani
- Department of Physics, Florida State University, Tallahassee, FL, USA.,Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, USA
| | | | - Michael J Previs
- Department of Molecular Physiology & Biophysics, University of Vermont College of Medicine, Burlington, VT, USA
| | - Kenneth A Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, USA
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29
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Previs MJ, Martin JL, Spees JL, O'Leary TS. Replacement of Myosin Molecules within Cardiac Thick Filaments in Intact Mouse Hearts. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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30
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Nelson SR, Li A, Rahmanseresht S, Braet F, Cornachione AS, Beck Previs S, O'Leary T, McNamara JW, Rassier DE, Sadayappan S, Previs MJ, Warshaw DM. Skeletal Myosin-Binding Protein C Isoforms Differentially Regulate Fast- and Slow-Twitch Skeletal Muscle Function. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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31
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Helms AS, Tang VT, O'Leary TS, Friedline S, Wauchope M, Arora A, Wasserman AH, Smith ED, Lee LM, Wen XW, Shavit JA, Liu AP, Previs MJ, Day SM. Effects of MYBPC3 loss-of-function mutations preceding hypertrophic cardiomyopathy. JCI Insight 2020; 5:133782. [PMID: 31877118 DOI: 10.1172/jci.insight.133782] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [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: 09/25/2019] [Accepted: 12/10/2019] [Indexed: 12/21/2022] Open
Abstract
Mutations in cardiac myosin binding protein C (MyBP-C, encoded by MYBPC3) are the most common cause of hypertrophic cardiomyopathy (HCM). Most MYBPC3 mutations result in premature termination codons (PTCs) that cause RNA degradation and a reduction of MyBP-C in HCM patient hearts. However, a reduction in MyBP-C has not been consistently observed in MYBPC3-mutant induced pluripotent stem cell cardiomyocytes (iPSCMs). To determine early MYBPC3 mutation effects, we used patient and genome-engineered iPSCMs. iPSCMs with frameshift mutations were compared with iPSCMs with MYBPC3 promoter and translational start site deletions, revealing that allelic loss of function is the primary inciting consequence of mutations causing PTCs. Despite a reduction in wild-type mRNA in all heterozygous iPSCMs, no reduction in MyBP-C protein was observed, indicating protein-level compensation through what we believe is a previously uncharacterized mechanism. Although homozygous mutant iPSCMs exhibited contractile dysregulation, heterozygous mutant iPSCMs had normal contractile function in the context of compensated MyBP-C levels. Agnostic RNA-Seq analysis revealed differential expression in genes involved in protein folding as the only dysregulated gene set. To determine how MYBPC3-mutant iPSCMs achieve compensated MyBP-C levels, sarcomeric protein synthesis and degradation were measured with stable isotope labeling. Heterozygous mutant iPSCMs showed reduced MyBP-C synthesis rates but a slower rate of MyBP-C degradation. These findings indicate that cardiomyocytes have an innate capacity to attain normal MyBP-C stoichiometry despite MYBPC3 allelic loss of function due to truncating mutations. Modulating MyBP-C degradation to maintain MyBP-C protein levels may be a novel treatment approach upstream of contractile dysfunction for HCM.
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Affiliation(s)
- Adam S Helms
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Vi T Tang
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Thomas S O'Leary
- Department of Molecular Physiology & Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Sabrina Friedline
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Mick Wauchope
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Akul Arora
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Eric D Smith
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | | | - Allen P Liu
- Mechanical Engineering.,Biophysics, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael J Previs
- Department of Molecular Physiology & Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Sharlene M Day
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.,Departments of Molecular and Integrative Physiology
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Barefield DY, Rahmanseresht S, O'Leary T, Sell JJ, Puckelwartz MJ, Wilsbacher LD, Previs MJ, McNally EM. Myosin Binding Protein H-Like Regulates Myofilament Content in Atrial and a Subset of Ventricular Conduction System Cardiomyocytes. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.1421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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33
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Inchingolo AV, Previs SB, Previs MJ, Warshaw DM, Kad NM. Single Molecule Visualization of Cardiac Myosin-Binding Protein C N-Terminal Fragments Interacting with Regulated Actin Filaments: Mechanisms of Calcium Sensitization. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Rahmanseresht S, Lee K, Robbins J, Warshaw DM, Craig R, Previs MJ. Resolving the Actin Lattice and Identifying the Relative Position of MYBP-C's N-Terminus in Cardiac Muscle using Storm Microscopy. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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O'Leary TS, Snyder J, Sadayappan S, Day SM, Previs MJ. MYBPC3 truncation mutations enhance actomyosin contractile mechanics in human hypertrophic cardiomyopathy. J Mol Cell Cardiol 2018; 127:165-173. [PMID: 30550750 DOI: 10.1016/j.yjmcc.2018.12.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/05/2018] [Accepted: 12/07/2018] [Indexed: 01/15/2023]
Abstract
RATIONALE Truncation mutations in the MYBPC3 gene, encoding for cardiac myosin-binding protein C (MyBP-C), are the leading cause of hypertrophic cardiomyopathy (HCM). Whole heart, fiber and molecular studies demonstrate that MyBP-C is a potent modulator of cardiac contractility, but how these mutations contribute to HCM is unresolved. OBJECTIVES To readdress whether MYBPC3 truncation mutations result in loss of MyBP-C content and/or the expression of truncated MyBP-C from the mutant allele and determine how these mutations effect myofilament sliding in human myocardium. METHODS AND RESULTS Septal wall tissue samples were obtained from HCM patients undergoing myectomy (n = 18) and donor controls (n = 8). The HCM samples contained 40% less MyBP-C and reduced levels of MyBP-C phosphorylation, when compared to the donor control samples using quantitative mass spectrometry. These differences occurred in the absence of changes in the stoichiometry of other myofilament proteins or production of truncated MyBP-C from the mutant MYBPC3 allele. The functional impact of MYBPC3 truncation mutations on myofilament sliding was determined using a total internal reflection microscopy (TIRFM) single particle assay. Myosin-thick filaments containing their native complement of MyBP-C, and actin-thin filaments decorated with the troponin/tropomyosin calcium regulatory proteins, were isolated from a subgroup of the HCM (n = 4) and donor (n = 5) heart samples. The maximal sliding velocity of native thin filaments was enhanced within the C-zones of the native thick filaments isolated from the HCM samples, when compared to velocity within the C-zones of thick filaments isolated from the donor samples. Analytical modeling demonstrated that the 40% reduction in MyBP-C content was sufficient to enhance the myofilament sliding velocity, as observed in the TIRFM assay. CONCLUSIONS HCM-causing MYBPC3 truncation mutations result in a loss of MyBP-C content that enhances maximal myofilament sliding velocities, only where MyBP-C is localized within the C-zone. These findings support therapeutic rationale for restoring normal levels of MyBP-C and/or dampening maximal contractile velocities for the treatment of human HCM.
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Affiliation(s)
- Thomas S O'Leary
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute of Vermont, University of Vermont, Burlington, VT, United States
| | - Julia Snyder
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute of Vermont, University of Vermont, Burlington, VT, United States
| | - Sakthivel Sadayappan
- Heart, Lung and Vascular Institute, Division of Cardiovascular Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Sharlene M Day
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute of Vermont, University of Vermont, Burlington, VT, United States.
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36
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Lin BL, Li A, Mun JY, Previs MJ, Previs SB, Campbell SG, Dos Remedios CG, Tombe PDP, Craig R, Warshaw DM, Sadayappan S. Skeletal myosin binding protein-C isoforms regulate thin filament activity in a Ca 2+-dependent manner. Sci Rep 2018; 8:2604. [PMID: 29422607 PMCID: PMC5805719 DOI: 10.1038/s41598-018-21053-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [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: 10/31/2017] [Accepted: 01/29/2018] [Indexed: 01/17/2023] Open
Abstract
Muscle contraction, which is initiated by Ca2+, results in precise sliding of myosin-based thick and actin-based thin filament contractile proteins. The interactions between myosin and actin are finely tuned by three isoforms of myosin binding protein-C (MyBP-C): slow-skeletal, fast-skeletal, and cardiac (ssMyBP-C, fsMyBP-C and cMyBP-C, respectively), each with distinct N-terminal regulatory regions. The skeletal MyBP-C isoforms are conditionally coexpressed in cardiac muscle, but little is known about their function. Therefore, to characterize the functional differences and regulatory mechanisms among these three isoforms, we expressed recombinant N-terminal fragments and examined their effect on contractile properties in biophysical assays. Addition of the fragments to in vitro motility assays demonstrated that ssMyBP-C and cMyBP-C activate thin filament sliding at low Ca2+. Corresponding 3D electron microscopy reconstructions of native thin filaments suggest that graded shifts of tropomyosin on actin are responsible for this activation (cardiac > slow-skeletal > fast-skeletal). Conversely, at higher Ca2+, addition of fsMyBP-C and cMyBP-C fragments reduced sliding velocities in the in vitro motility assays and increased force production in cardiac muscle fibers. We conclude that due to the high frequency of Ca2+ cycling in cardiac muscle, cardiac MyBP-C may play dual roles at both low and high Ca2+. However, skeletal MyBP-C isoforms may be tuned to meet the needs of specific skeletal muscles.
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Affiliation(s)
- Brian Leei Lin
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Amy Li
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05405, USA
- Bosch Institute, Discipline of Anatomy and Histology, University of Sydney, Sydney, 2006, Australia
| | - Ji Young Mun
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, 01655, USA
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, Dong-gu, Daegu, Korea
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05405, USA
| | - Samantha Beck Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05405, USA
| | - Stuart G Campbell
- Departments of Biomedical Engineering and Cellular and Molecular Physiology, Yale University, New Haven, CT, 06520, USA
| | - Cristobal G Dos Remedios
- Bosch Institute, Discipline of Anatomy and Histology, University of Sydney, Sydney, 2006, Australia
| | - Pieter de P Tombe
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Roger Craig
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, 01655, USA
| | - David M Warshaw
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05405, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL, 60153, USA.
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37
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Rahmanseresht S, Michalek AJ, Gulick J, Robbins J, Warshaw DM, Previs MJ. Super-Stable Phosphorylation Dependent Intramolecular Interactions Regulate the Structure and Function of MyBP-C. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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38
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Rahmanseresht S, Lee K, Robbins J, Warshaw DM, Craig R, Previs MJ. Pushing the Boundary of Storm Resolution: Seeing the Actin Lattice in Muscle. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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39
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Bookwalter CS, Tay CL, McCrorie R, Previs MJ, Lu H, Krementsova EB, Fagnant PM, Baum J, Trybus KM. Reconstitution of the core of the malaria parasite glideosome with recombinant Plasmodium class XIV myosin A and Plasmodium actin. J Biol Chem 2017; 292:19290-19303. [PMID: 28978649 PMCID: PMC5702669 DOI: 10.1074/jbc.m117.813972] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [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: 08/23/2017] [Revised: 09/27/2017] [Indexed: 11/08/2022] Open
Abstract
Motility of the apicomplexan malaria parasite Plasmodium falciparum is enabled by a multiprotein glideosome complex, whose core is the class XIV myosin motor, PfMyoA, and a divergent Plasmodium actin (PfAct1). Parasite motility is necessary for host-cell invasion and virulence, but studying its molecular basis has been hampered by unavailability of sufficient amounts of PfMyoA. Here, we expressed milligram quantities of functional full-length PfMyoA with the baculovirus/Sf9 cell expression system, which required a UCS (UNC-45/CRO1/She4p) family myosin chaperone from Plasmodium spp. In addition to the known light chain myosin tail interacting protein (MTIP), we identified an essential light chain (PfELC) that co-purified with PfMyoA isolated from parasite lysates. The speed at which PfMyoA moved actin was fastest with both light chains bound, consistent with the light chain–binding domain acting as a lever arm to amplify nucleotide-dependent motions in the motor domain. Surprisingly, PfELC binding to the heavy chain required that MTIP also be bound to the heavy chain, unlike MTIP that bound the heavy chain independently of PfELC. Neither the presence of calcium nor deletion of the MTIP N-terminal extension changed the speed of actin movement. Of note, PfMyoA moved filaments formed from Sf9 cell–expressed PfAct1 at the same speed as skeletal muscle actin. Duty ratio estimates suggested that as few as nine motors can power actin movement at maximal speed, a feature that may be necessitated by the dynamic nature of Plasmodium actin filaments in the parasite. In summary, we have reconstituted the essential core of the glideosome, enabling drug targeting of both of its core components to inhibit parasite invasion.
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Affiliation(s)
- Carol S Bookwalter
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Chwen L Tay
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Rama McCrorie
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Michael J Previs
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Hailong Lu
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Elena B Krementsova
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Patricia M Fagnant
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Jake Baum
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Kathleen M Trybus
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
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40
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Inchingolo AV, Previs MJ, Beck Previs SE, Kad NM, Warshaw DM. Direct Single Molecule Visualization of Cardiac MyBP-C N-Terminal Fragment Interactions with Suspended Thin Filaments. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.2613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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41
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Swenson AM, Tang W, Blair CA, Fetrow CM, Unrath WC, Previs MJ, Campbell KS, Yengo CM. Omecamtiv Mecarbil Enhances the Duty Ratio of Human β-Cardiac Myosin Resulting in Increased Calcium Sensitivity and Slowed Force Development in Cardiac Muscle. J Biol Chem 2017; 292:3768-3778. [PMID: 28082673 DOI: 10.1074/jbc.m116.748780] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 01/05/2017] [Indexed: 01/10/2023] Open
Abstract
The small molecule drug omecamtiv mecarbil (OM) specifically targets cardiac muscle myosin and is known to enhance cardiac muscle performance, yet its impact on human cardiac myosin motor function is unclear. We expressed and purified human β-cardiac myosin subfragment 1 (M2β-S1) containing a C-terminal Avi tag. We demonstrate that the maximum actin-activated ATPase activity of M2β-S1 is slowed more than 4-fold in the presence of OM, whereas the actin concentration required for half-maximal ATPase was reduced dramatically (30-fold). We find OM does not change the overall actin affinity. Transient kinetic experiments suggest that there are two kinetic pathways in the presence of OM. The dominant pathway results in a slow transition between actomyosin·ADP states and increases the time myosin is strongly bound to actin. However, OM also traps a population of myosin heads in a weak actin affinity state with slow product release. We demonstrate that OM can reduce the actin sliding velocity more than 100-fold in the in vitro motility assay. The ionic strength dependence of in vitro motility suggests the inhibition may be at least partially due to drag forces from weakly attached myosin heads. OM causes an increase in duty ratio examined in the motility assay. Experiments with permeabilized human myocardium demonstrate that OM increases calcium sensitivity and slows force development (ktr) in a concentration-dependent manner, whereas the maximally activated force is unchanged. We propose that OM increases the myosin duty ratio, which results in enhanced calcium sensitivity but slower force development in human myocardium.
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Affiliation(s)
- Anja M Swenson
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Wanjian Tang
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Cheavar A Blair
- the Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky 40536-0298, and
| | - Christopher M Fetrow
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - William C Unrath
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Michael J Previs
- the Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, Vermont 05405
| | - Kenneth S Campbell
- the Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky 40536-0298, and
| | - Christopher M Yengo
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033,
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42
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Lynch TL, Kuster DW, Sivaguru M, Previs MJ, Lee K, Govindan S, Craig R, Warshaw DM, Sadayappan S. Abstract 389: Amino Terminal Region of Cardiac Myosin Binding Protein-C is Necessary for Cardiac Function. Circ Res 2016. [DOI: 10.1161/res.119.suppl_1.389] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rationale:
Cardiac myosin binding protein-C (cMyBP-C) is a thick filament-associated protein that has been suggested to regulate cardiac contraction via its amino terminal (N’) region. However, the necessity of the N’-C0-C1f region (domains C0 through C1 and the first 17 residues of the M-domain) of cMyBP-C in regulating cardiac function
in vivo
has not been elucidated.
Hypothesis:
The N’-C0-C1f region of cMyBP-C is critical for normal cardiac function
in vivo
.
Methods and Results:
Transgenic mice with 80±4% expression of a truncated cMyBP-C missing the N’-C0-C1f region (cMyBP-C
110kDa
) were generated and characterized at 3-months of age. cMyBP-C
110kDa
animals exhibited cardiac hypertrophy as suggested by an increased heart weight to body weight ratio (5.0±0.1 mg/g NTG vs. 6.9±0.1 mg/g cMyBP-C
110kDa
, p<0.0001) and an elevation in pathological hypertrophy markers determined by real-time PCR. Histopathological analysis showed increased cardiac fibrosis in cMyBP-C
110kDa
hearts compared to hearts from non-transgenic (NTG) littermates. Intriguingly, increased phosphorylation of cMyBP-C at Ser-282 and Ser-302, sites important for cMyBP-C’s regulation of actomyosin interactions, was observed in cMyBP-C
110kDa
hearts compared to controls. Electron microscopy revealed normal sarcomere structure in cMyBP-C
110kDa
hearts but with apparently weaker cMyBP-C stripes. Furthermore, the ability of cMyBP-C to slow actin-filament sliding within the C-zone of native thick filaments isolated from NTG hearts was lost on thick filaments from cMyBP-C
110kDa
hearts. Short-axis M-mode echocardiography indicated a significant elevation in left ventricular internal diameter and a significant reduction in fractional shortening (31±5% NTG vs. 16±3% cMyBP-C
110kDa
, p=0.0003) in cMyBP-C
110kDa
hearts compared to controls. Finally, global longitudinal strain analysis revealed abnormal wall motion in cMyBP-C
110kDa
hearts. Based upon these data, we propose that the N’-region of cMyBP-C is a critical regulator of actomyosin interactions and controls aberrant contraction kinetics within the cardiac sarcomere.
Conclusion:
The N’-C0-C1f region of cMyBP-C regulates cardiac contractility and is necessary for maintaining normal cardiac function
in vivo
.
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Affiliation(s)
| | | | | | | | | | | | - Roger Craig
- Univ of Massachusetts Med Sch, Worcester, MA
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Sivaguru M, Lynch TL, Kuster DW, Govindan S, Sadayappan S, Previs MJ, Warshaw DM, Lee K, Craig R. ID: 136: N-TERMINAL REGION OF CARDIAC MYOSIN BINDING PROTEIN-C IS NECESSARY FOR CARDIAC FUNCTION. J Investig Med 2016. [DOI: 10.1136/jim-2016-000120.2] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
RationaleCardiac myosin binding protein-C (cMyBP-C) is a trans-filament protein that has been shown to regulate cardiac function via its amino terminal (N′) region. In vitro studies have suggested the importance of the first 271 N′-residues of cMyBP-C (C0-C1f region) in slowing actin filament sliding over myosin to regulate cross-bridge cycling kinetics within the cardiac sarcomere. However, the role and necessity of the C0-C1f region of cMyBP-C in regulating contractile and cardiac function in vivo have not been elucidated.HypothesisThe N′-C0-C1f region of cMyBP-C is critical for proper cardiac function in vivo.Methods and ResultsTransgenic mice with approximately 95% expression of a mutant truncated cMyBP-C missing the N′-C0-C1f region (cMyBP-C110 kDa), compared to endogenous cMyBP-C, were generated and characterized at 3-months of age. cMyBP-C110 kDa hearts had significantly elevated heart weight/body weight ratio, fibrosis, nuclear area and collagen content compared to hearts from non-transgenic (NTG) littermates. Electron microscopic analysis revealed normal sarcomere structure in cMyBP-C110 kDa hearts but with apparently weaker cMyBP-C stripes. Furthermore, the ability of cMyBP-C to slow actin-filament sliding within the C-zone of native thick filaments isolated from NTG hearts was lost on thick filaments from cMyBP-C110 kDa hearts. Short axis M-mode echocardiography revealed a significant increase in left ventricular (LV) internal diameter during diastole in cMyBP-C110 kDa hearts. Importantly, cMyBP-C110 kDa hearts displayed a significant reduction in fractional shortening compared to hearts from NTG mice. We further observed a decrease in the thickness of the LV interventricular septum and free wall during systole in cMyBP-C110 kDa hearts. Strain analysis using images acquired from ECG-Gated Kilohertz Visualization identified a significant deficit in global longitudinal strain in cMyBP-C110 kDa hearts compared to NTG hearts. Consistent with cardiac hypertrophy, we observed a significant increase in the expression of the hypertrophic genes MYH7 and NPPA by real-time PCR analysis. As expected, the expression levels of the MYBPC3 gene were significantly elevated in cMyBP-C110 kDa hearts compared to NTG hearts. Surprisingly, our Western blot analyses revealed no significant difference in total cMyBP-C levels between NTG and cMyBP-C110 kDa heart homogenates. However, intriguingly, we observed a significant elevation in cMyBP-C phosphorylation at Ser-273, Ser-282, and Ser-302, sites important for cMyBP-C's regulation of actomyosin interaction, in cMyBP-C110 kDa heart homogenates compared to those from NTG mice.ConclusionThe N′-C0-C1f region of cMyBP-C is essential for maintaining normal cardiac morphology and function in vivo and loss of this region promotes contractile dysfunction both at the molecular and tissue level.
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44
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Previs MJ, Young Mun J, Michalek AJ, Beck Previs S, Gulick J, Robbins J, Warshaw DM, Craig R. Phosphorylation and Calcium Antagonistically Tune Myosin-Binding Protein C's Molecular Structure and Function. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.1583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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45
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Lynch TL, Kuster DW, Barefield D, Sivaguru M, Previs MJ, Lee K, Govindan S, Craig R, Warshaw DM, Sadayappan S. Abstract 376: Amino Terminal C0-C1f Region of Cardiac Myosin Binding Protein-C is Essential for Normal Cardiac Function. Circ Res 2015. [DOI: 10.1161/res.117.suppl_1.376] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rationale:
Cardiac myosin binding protein-C (cMyBP-C) is a trans-filament protein that has been shown to regulate cardiac function via its amino terminal (N’) regions. However, it is unknown whether the first 271 residues (C0-C1f region) are necessary to regulate contractile function in vivo.
Hypothesis:
The N’-region of cMyBP-C is critical for proper cardiac function in vivo.
Methods and Results:
Transgenic mice with approximately 80% expression of mutant truncated cMyBP-C missing C0-C1f (cMyBP-C
110kDa
), compared to endogenous cMyBP-C, were generated and characterized at 3-months of age. cMyBP-C
110kDa
hearts had significantly elevated heart weight/body weight ratio, fibrosis, nuclear area and collagen content compared to hearts from non-transgenic (NTG) littermates. Electron microscopic analysis revealed normal sarcomere structure in cMyBP-C
110kDa
hearts but with apparently weaker cMyBP-C stripes. Furthermore, the ability of cMyBP-C to slow actin-filament sliding within the C-zone of native thick filaments isolated from NTG hearts was lost on thick filaments from cMyBP-C
110kDa
hearts. Short axis M-mode echocardiography revealed a significant increase in left ventricular (LV) internal diameter during diastole in cMyBP-C
110kDa
hearts. Importantly, cMyBP-C
110kDa
hearts displayed a significant reduction in fractional shortening compared to hearts from NTG littermates. We further observed a decrease in the thickness of the LV interventricular septum and free wall during systole in cMyBP-C
110kDa
hearts. Strain analysis using images acquired from ECG-Gated Kilohertz Visualization identified a significant deficit in global longitudinal strain in cMyBP-C
110kDa
hearts compared to NTG hearts.
Conclusion:
The N’-region of cMyBP-C is indispensable for maintaining normal cardiac morphology and function and loss of this region promotes contractile dysfunction both at the molecular and tissue levels.
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Affiliation(s)
| | | | | | | | | | | | | | - Roger Craig
- Univ of Massachusetts Med Sch, Worcester, MA
| | | | | |
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46
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Woodward M, Previs MJ, Mader TJ, Debold EP. Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model. Front Physiol 2015; 6:199. [PMID: 26236240 PMCID: PMC4503891 DOI: 10.3389/fphys.2015.00199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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: 05/21/2015] [Accepted: 06/29/2015] [Indexed: 12/27/2022] Open
Abstract
Cardiac arrest is a prevalent condition with a poor prognosis, attributable in part to persistent myocardial dysfunction following resuscitation. The molecular basis of this dysfunction remains unclear. We induced cardiac arrest in a porcine model of acute sudden death and assessed the impact of ischemia and reperfusion on the molecular function of isolated cardiac contractile proteins. Cardiac arrest was electrically induced, left untreated for 12 min, and followed by a resuscitation protocol. With successful resuscitations, the heart was reperfused for 2 h (IR2) and the muscle harvested. In failed resuscitations, tissue samples were taken following the failed efforts (IDNR). Actin filament velocity, using myosin isolated from IR2 or IDNR cardiac tissue, was nearly identical to myosin from the control tissue in a motility assay. However, both maximal velocity (25% faster than control) and calcium sensitivity (pCa50 6.57 ± 0.04 IDNR vs. 6.34 ± 0.07 control) were significantly (p < 0.05) enhanced using native thin filaments (actin+troponin+tropomyosin) from IDNR samples, suggesting that the enhanced velocity is mediated through an alteration in muscle regulatory proteins (troponin+tropomyosin). Mass spectrometry analysis showed that only samples from the IR2 had an increase in total phosphorylation levels of troponin (Tn) and tropomyosin (Tm), but both IR2 and IDNR samples demonstrated a significant shift from mono-phosphorylated to bis-phosphorylated forms of the inhibitory subunit of Tn (TnI) compared to control. This suggests that the shift to bis-phosphorylation of TnI is associated with the enhanced function in IDNR, but this effect may be attenuated when phosphorylation of Tm is increased in tandem, as observed for IR2. There are likely many other molecular changes induced following cardiac arrest, but to our knowledge, these data provide the first evidence that this form cardiac arrest can alter the in vitro function of the cardiac contractile proteins.
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Affiliation(s)
- Mike Woodward
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, MA, USA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of Vermont Burlington, VT, USA
| | - Timothy J Mader
- Department of Emergency Medicine, Baystate Medical Center/Tufts University School of Medicine Springfield, MA, USA
| | - Edward P Debold
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, MA, USA ; Muscle Biophysics Lab, Department of Kinesiology, University of Massachusetts Amherst, MA, USA
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47
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Previs MJ, Prosser BL, Mun JY, Previs SB, Gulick J, Lee K, Robbins J, Craig R, Lederer WJ, Warshaw DM. Myosin-binding protein C corrects an intrinsic inhomogeneity in cardiac excitation-contraction coupling. Sci Adv 2015; 1:e1400205. [PMID: 25839057 PMCID: PMC4380226 DOI: 10.1126/sciadv.1400205] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 01/04/2015] [Indexed: 05/30/2023]
Abstract
The beating heart exhibits remarkable contractile fidelity over a lifetime, which reflects the tight coupling of electrical, chemical, and mechanical elements within the sarcomere, the elementary contractile unit. On a beat-to-beat basis, calcium is released from the ends of the sarcomere and must diffuse toward the sarcomere center to fully activate the myosin- and actin-based contractile proteins. The resultant spatial and temporal gradient in free calcium across the sarcomere should lead to nonuniform and inefficient activation of contraction. We show that myosin-binding protein C (MyBP-C), through its positioning on the myosin thick filaments, corrects this nonuniformity in calcium activation by exquisitely sensitizing the contractile apparatus to calcium in a manner that precisely counterbalances the calcium gradient. Thus, the presence and correct localization of MyBP-C within the sarcomere is critically important for normal cardiac function, and any disturbance of MyBP-C localization or function will contribute to the consequent cardiac pathologies.
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Affiliation(s)
- Michael J. Previs
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute of Vermont, The University of Vermont, Burlington, VT 05405, USA
| | - Benjamin L. Prosser
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ji Young Mun
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Department of Biomedical Laboratory Science, College of Health Sciences, Eulji University, Seongnam-Si 461-701, Gyeonggi-Do, Republic of Korea
| | - Samantha Beck Previs
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute of Vermont, The University of Vermont, Burlington, VT 05405, USA
| | - James Gulick
- Department of Pediatrics and the Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Kyounghwan Lee
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jeffrey Robbins
- Department of Pediatrics and the Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Roger Craig
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - W. J. Lederer
- Department of Physiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - David M. Warshaw
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute of Vermont, The University of Vermont, Burlington, VT 05405, USA
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48
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Previs MJ, Prosser BL, Mun JY, Beck Previs S, Gulick J, Lee K, Robbins J, Craig R, Lederer WJ, Warshaw DM. Myosin-Binding Protein C Corrects an Intrinsic Non-Uniformity in Cardiac Excitation-Contraction Coupling. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.1984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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49
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Previs MJ, Michalek AJ, Warshaw DM. Molecular modulation of actomyosin function by cardiac myosin-binding protein C. Pflugers Arch 2014; 466:439-44. [PMID: 24407948 DOI: 10.1007/s00424-013-1433-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/23/2013] [Indexed: 11/29/2022]
Abstract
Cardiac myosin-binding protein C is a key regulator of cardiac contractility and is capable of both activating the thin filament to initiate actomyosin motion generation and governing maximal sliding velocities. While MyBP-C's C terminus localizes the molecule within the sarcomere, the N terminus appears to confer regulatory function by binding to the myosin motor domain and/or actin. Literature pertaining to how MyBP-C binding to the myosin motor domain and or actin leads to MyBP-C's dual modulatory roles that can impact actomyosin interactions are discussed.
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Affiliation(s)
- Michael J Previs
- Department of Molecular Physiology & Biophysics, University of Vermont, 149 Beaumont Ave., HSRF Building Rm.-116, Burlington, VT, 05405, USA
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50
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Michalek AJ, Howarth JW, Gulick J, Previs MJ, Robbins J, Rosevear PR, Warshaw DM. Phosphorylation modulates the mechanical stability of the cardiac myosin-binding protein C motif. Biophys J 2013; 104:442-52. [PMID: 23442866 DOI: 10.1016/j.bpj.2012.12.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 12/12/2012] [Accepted: 12/14/2012] [Indexed: 01/21/2023] Open
Abstract
Cardiac myosin-binding protein C (cMyBP-C) is a thick-filament-associated protein that modulates cardiac contractility through interactions of its N-terminal immunoglobulin (Ig)-like C0-C2 domains with actin and/or myosin. These interactions are modified by the phosphorylation of at least four serines located within the motif linker between domains C1 and C2. We investigated whether motif phosphorylation alters its mechanical properties by characterizing force-extension relations using atomic force spectroscopy of expressed mouse N-terminal cMyBP-C fragments (i.e., C0-C3). Protein kinase A phosphorylation or serine replacement with aspartic acids did not affect persistence length (0.43 ± 0.04 nm), individual Ig-like domain unfolding forces (118 ± 3 pN), or Ig extension due to unfolding (30 ± 0.38 nm). However, phosphorylation did significantly decrease the C0-C3 mean contour length by 24 ± 2 nm. These results suggest that upon phosphorylation, the motif, which is freely extensible in the nonphosphorylated state, adopts a more stable and/or different structure. Circular dichroism and dynamic light scattering data for shorter expressed C1-C2 fragments with all four serines replaced by aspartic acids confirmed that the motif did adopt a more stable structure that was not apparent in the nonphosphorylated motif. These biophysical data provide both a mechanical and structural basis for cMyBP-C regulation by motif phosphorylation.
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Affiliation(s)
- Arthur J Michalek
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, USA
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