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Morck MM, Bhowmik D, Pathak D, Dawood A, Spudich J, Ruppel KM. Hypertrophic cardiomyopathy mutations in the pliant and light chain-binding regions of the lever arm of human β-cardiac myosin have divergent effects on myosin function. eLife 2022; 11:e76805. [PMID: 35767336 PMCID: PMC9242648 DOI: 10.7554/elife.76805] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 06/12/2022] [Indexed: 11/13/2022] Open
Abstract
Mutations in the lever arm of β-cardiac myosin are a frequent cause of hypertrophic cardiomyopathy, a disease characterized by hypercontractility and eventual hypertrophy of the left ventricle. Here, we studied five such mutations: three in the pliant region of the lever arm (D778V, L781P, and S782N) and two in the light chain-binding region (A797T and F834L). We investigated their effects on both motor function and myosin subfragment 2 (S2) tail-based autoinhibition. The pliant region mutations had varying effects on the motor function of a myosin construct lacking the S2 tail: overall, D778V increased power output, L781P reduced power output, and S782N had little effect on power output, while all three reduced the external force sensitivity of the actin detachment rate. With a myosin containing the motor domain and the proximal S2 tail, the pliant region mutations also attenuated autoinhibition in the presence of filamentous actin but had no impact in the absence of actin. By contrast, the light chain-binding region mutations had little effect on motor activity but produced marked reductions in autoinhibition in both the presence and absence of actin. Thus, mutations in the lever arm of β-cardiac myosin have divergent allosteric effects on myosin function, depending on whether they are in the pliant or light chain-binding regions.
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Affiliation(s)
- Makenna M Morck
- Stanford Cardiovascular Institute, Stanford University School of MedicineStanfordUnited States
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | - Debanjan Bhowmik
- Stanford Cardiovascular Institute, Stanford University School of MedicineStanfordUnited States
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | - Divya Pathak
- Stanford Cardiovascular Institute, Stanford University School of MedicineStanfordUnited States
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | - Aminah Dawood
- Stanford Cardiovascular Institute, Stanford University School of MedicineStanfordUnited States
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | - James Spudich
- Stanford Cardiovascular Institute, Stanford University School of MedicineStanfordUnited States
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | - Kathleen M Ruppel
- Stanford Cardiovascular Institute, Stanford University School of MedicineStanfordUnited States
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
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Schroer A, Jung G, Kooiker K, Adhikari A, Song L, Liu C, Ruppel K, Wu S, Pruitt B, Spudich J, Bernstein D. Abstract 212: Hypertrophic Cardiomyopathy Mutations With Opposite Effects on ß-myosin Biomechanics Show Similar Structural and Biomechanical Phenotypes in Human Induced Pluripotent Stem Cell Derived Cardiomyocytes (hipsc-cms). Circ Res 2019. [DOI: 10.1161/res.125.suppl_1.212] [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
Introduction:
Hypertrophic cardiomyopathy (HCM) is the most prevalent heritable cardiovascular disease, commonly caused by mutations in beta cardiac myosin heavy chain (βMYH). We have measured the kinetics of isolated myosin proteins with different HCM mutations in βMYH and found an intriguing heterogeneity in kinetics and force production: some mutations increase whereas others decrease force and velocity; others result in no change. How these divergent molecular alterations converge to the final HCM phenotype: hypercontractility and cellular hypertrophy is still unknown. hiPSC-CMs provide a powerful tool for studying human cardiomyocyte biology including contractility, hypertrophic growth, and intracellular organization, but are limited by immature phenotypes and population heterogeneity in traditional culture environments.
Methods and Results:
We developed a micropatterned hydrogel platform that enhances force generation and promotes both structural and molecular hiPSC-CM maturation. Using CRISPR/Cas-9 gene editing in an isogenic hiPSC line, we created hiPSCs with two different βMYH mutations (P710R and D239N) that result in opposite effects on force at the molecular level, using in vitro motility and laser trap methods. Cell morphology was quantified by both fluorescence and transmission electron microscopy (EM) and force generation measured by traction force microscopy. Despite having opposite effects at the single molecule level, both HCM lines showed increased contractile force and cellular hypertrophy compared to isogenic controls. Immunostaining for βMYH and EM revealed organizational and microstructural changes including sarcomere and myofibrillar disarray, and thickened z-discs in cells containing these mutations. Both mutations had alterations in AMPK, MAPK, and calcineurin signaling shown to regulate hypertrophy.
Discussion:
Divergent biomechanical alterations due to HCM mutations at the single molecule level lead to common cellular-level structural and biomechanical phenotypes through activation of common signaling pathways.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Beth Pruitt
- Univ of California Santa Barbara, Santa Barbara, CA
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Spudich J. The Myosin Mesa and Hypertrophic Cardiomyopathy: Mutations to Mechanisms to Therapies. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.233] [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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4
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Arnholt M, Bohn M, Cina M, Downing A, Flanagan M, Hautala L, Jaeke A, Kennedy C, Lane B, O'Bryon A, Pepin J, Rohloff E, Rrahmani F, Schmitt S, Spudich J, Staus S, Tadlock K, Tomashek M, Witt E, McNally M. Serine Rich Splicing Factor 2 (SRSF2) Flips for RNA Binding. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.lb203] [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: 11/11/2022]
Affiliation(s)
| | - M. Bohn
- Hartford Union High SchoolHartfordWI
| | - M. Cina
- Hartford Union High SchoolHartfordWI
| | | | | | | | - A. Jaeke
- Hartford Union High SchoolHartfordWI
| | | | - B. Lane
- Hartford Union High SchoolHartfordWI
| | | | - J. Pepin
- Hartford Union High SchoolHartfordWI
| | | | | | | | | | - S. Staus
- Hartford Union High SchoolHartfordWI
| | | | | | - E. Witt
- Hartford Union High SchoolHartfordWI
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Schroer A, Kooiker K, Adhikari A, Ruppel K, Bernstein D, Spudich J, Pruitt B. Mechanobiology of Myosin Mutations and Myofibril Remodeling in iPSC-Cardiomyocytes. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2720] [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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6
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Spudich J, Nag S, Sutton S, Sarkar S, Taylor R, Trivedi D, Liu C, Adhikari A, Ruppel K. On the Molecular Basis of Monogenic Human Hypertrophic and Dilated Cardiomyopathies. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.096] [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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7
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Manor U, Bartholomew S, Golani G, Christenson E, Kozlov M, Higgs H, Spudich J, Lippincott-Schwartz J. A mitochondria-anchored isoform of the actin-nucleating spire protein regulates mitochondrial division. eLife 2015; 4. [PMID: 26305500 PMCID: PMC4574297 DOI: 10.7554/elife.08828] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/24/2015] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial division, essential for survival in mammals, is enhanced by an inter-organellar process involving ER tubules encircling and constricting mitochondria. The force for constriction is thought to involve actin polymerization by the ER-anchored isoform of the formin protein inverted formin 2 (INF2). Unknown is the mechanism triggering INF2-mediated actin polymerization at ER-mitochondria intersections. We show that a novel isoform of the formin-binding, actin-nucleating protein Spire, Spire1C, localizes to mitochondria and directly links mitochondria to the actin cytoskeleton and the ER. Spire1C binds INF2 and promotes actin assembly on mitochondrial surfaces. Disrupting either Spire1C actin- or formin-binding activities reduces mitochondrial constriction and division. We propose Spire1C cooperates with INF2 to regulate actin assembly at ER-mitochondrial contacts. Simulations support this model's feasibility and demonstrate polymerizing actin filaments can induce mitochondrial constriction. Thus, Spire1C is optimally positioned to serve as a molecular hub that links mitochondria to actin and the ER for regulation of mitochondrial division. DOI:http://dx.doi.org/10.7554/eLife.08828.001 Mitochondria are structures within cells that provide the energy to power many biological processes that are essential for complex life. These structures are also highly dynamic and go through cycles of fission (in which a single mitochondrion splits in two) and fusion (in which two mitochondria merge into one). These processes both maintain the correct number of mitochondria in a cell and remove damaged ones, and defects in either can result in many diseases. Previous research had shown that mitochondria are in close contact with another cellular structure called the endoplasmic reticulum. The points of contact mark the sites where mitochondria undergo fission, as small tubes of the endoplasmic reticulum wrap around, and then constrict, to split a mitochondrion. Other recent work revealed that a protein called INF2 is anchored on the endoplasmic reticulum where it promotes mitochondrial constriction. This protein builds actin subunits into long filaments that provide the force for constriction. However, it was not clear how INF2 became active, and whether there are proteins on mitochondria that interact with INF2 or actin. Manor, Bartholomew et al. have now used a combination of microscopy-based methods and biochemical analysis to discover that a mitochondrial protein called Spire1C performs all of these roles. Spire1C is found on the outer membrane of mitochondria; it interacts with INF2 to drive the formation of actin filaments that constrict mitochondria. These results suggest that Spire1C bridges the endoplasmic reticulum with the network of actin filaments. Further experiments then showed that increasing Spire1C levels in cells resulted in the mitochondria becoming fragmented due to increased constriction. On the other hand, depleting Spire1C had the opposite effect and caused mitochondria to become unusually elongated. Following on from this work, the next challenge is to see if Spire1C is used differently or similarly in the different processes that involve mitochondrial fission. DOI:http://dx.doi.org/10.7554/eLife.08828.002
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Affiliation(s)
- Uri Manor
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, United States
| | - Sadie Bartholomew
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
| | - Gonen Golani
- Department of Physiology and Pharmacology, Tel Aviv University, Tel Aviv, Israel
| | - Eric Christenson
- Unit on Structural and Chemical Biology of Membrane Proteins, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, United States
| | - Michael Kozlov
- Department of Physiology and Pharmacology, Tel Aviv University, Tel Aviv, Israel
| | - Henry Higgs
- Department of Biochemistry, Geisel School of Medicine, Hanover, United States
| | - James Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
| | - Jennifer Lippincott-Schwartz
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, United States
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Mendez D, Lane TJ, Sung J, Sellberg J, Levard C, Watkins H, Cohen AE, Soltis M, Sutton S, Spudich J, Pande V, Ratner D, Doniach S. Observation of correlated X-ray scattering at atomic resolution. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130315. [PMID: 24914148 PMCID: PMC4052857 DOI: 10.1098/rstb.2013.0315] [Citation(s) in RCA: 33] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tools to study disordered systems with local structural order, such as proteins in solution, remain limited. Such understanding is essential for e.g. rational drug design. Correlated X-ray scattering (CXS) has recently attracted new interest as a way to leverage next-generation light sources to study such disordered matter. The CXS experiment measures angular correlations of the intensity caused by the scattering of X-rays from an ensemble of identical particles, with disordered orientation and position. Averaging over 15 496 snapshot images obtained by exposing a sample of silver nanoparticles in solution to a micro-focused synchrotron radiation beam, we report on experimental efforts to obtain CXS signal from an ensemble in three dimensions. A correlation function was measured at wide angles corresponding to atomic resolution that matches theoretical predictions. These preliminary results suggest that other CXS experiments on disordered ensembles—such as proteins in solution—may be feasible in the future.
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Affiliation(s)
- Derek Mendez
- Department of Applied Physics, Menlo Park, CA 94025, USA
| | | | - Jongmin Sung
- Department of Applied Physics, Menlo Park, CA 94025, USA Department of Biochemistry, Stanford University School of Medicine, Menlo Park, CA 94025, USA
| | - Jonas Sellberg
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA Department of Physics, AlbaNova University Center, Stockholm University, S-106 91 Stockholm, Sweden
| | - Clément Levard
- Department of Geological and Environmental Sciences, Stanford University, Stanford CA 94305, USA Aix-Marseille University, CNRS, IRD, CEREGE UM34, 13545 Aix-en-Provence, France
| | | | - Aina E Cohen
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Michael Soltis
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Shirley Sutton
- Department of Biochemistry, Stanford University School of Medicine, Menlo Park, CA 94025, USA
| | - James Spudich
- Department of Biochemistry, Stanford University School of Medicine, Menlo Park, CA 94025, USA
| | - Vijay Pande
- Department of Chemistry, Menlo Park, CA 94025, USA
| | - Daniel Ratner
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Sebastian Doniach
- Department of Applied Physics, Menlo Park, CA 94025, USA SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
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Nag S, Sommese R, Sutton S, Ruppel K, Spudich J. Effects of Hypertrophic Cardiomyopathy Causing R403Q Mutation on Human Beta-Cardiac Myosin Biomechanical Function: Single Molecule to Ensemble Studies. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.2432] [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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10
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Aksel T, Kawana M, Adhikari A, Sutton S, Ruppel K, Spudich J. Improved Loaded In Vitro Motility Assay and Actin Filament Tracking Software Delineates the Effect of Hypertrophic and Dilated Cardiomyopathy Mutations on the Power Output of Cardiac Myosin. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.3122] [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: 10/23/2022] Open
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11
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Sung J, Nag S, Vestergaard C, Mortensen K, Flyvbjerg H, Spudich J. Harmonic Force Spectroscopy Reveals a Force-Velocity Curve from a Single Human Beta Cardiac Myosin Motor. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.2566] [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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12
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Affiliation(s)
- James Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
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13
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Spudich J. Hugh E. Huxley (1924–2013). Curr Biol 2013. [DOI: 10.1016/j.cub.2013.08.004] [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: 10/26/2022]
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Liang W, Licate L, Warrick H, Spudich J, Egelhoff T. Differential localization in cells of myosin II heavy chain kinases during cytokinesis and polarized migration. BMC Cell Biol 2002; 3:19. [PMID: 12139770 PMCID: PMC119860 DOI: 10.1186/1471-2121-3-19] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [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: 04/02/2002] [Accepted: 07/24/2002] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Cortical myosin-II filaments in Dictyostelium discoideum display enrichment in the posterior of the cell during cell migration, and in the cleavage furrow during cytokinesis. Filament assembly in turn is regulated by phosphorylation in the tail region of the myosin heavy chain (MHC). Early studies have revealed one enzyme, MHCK-A, which participates in filament assembly control, and two other structurally related enzymes, MHCK-B and -C. In this report we evaluate the biochemical properties of MHCK-C, and using fluorescence microscopy in living cells we examine the localization of GFP-labeled MHCK-A, -B, and -C in relation to GFP-myosin-II localization. RESULTS Biochemical analysis indicates that MHCK-C can phosphorylate MHC with concomitant disassembly of myosin II filaments. In living cells, GFP-MHCK-A displayed frequent enrichment in the anterior of polarized migrating cells, and in the polar region but not the furrow during cytokinesis. GFP-MHCK-B generally displayed a homogeneous distribution. In migrating cells GFP-MHCK-C displayed posterior enrichment similar to that of myosin II, but did not localize with myosin II to the furrow during the early stage of cytokinesis. At the late stage of cytokinesis, GFP-MHCK-C became strongly enriched in the cleavage furrow, remaining there through completion of division. CONCLUSION MHCK-A, -B, and -C display distinct cellular localization patterns suggesting different cellular functions and regulation for each MHCK isoform. The strong localization of MHCK-C to the cleavage furrow in the late stages of cell division may reflect a mechanism by which the cell regulates the progressive removal of myosin II as furrowing progresses.
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Affiliation(s)
- Wenchuan Liang
- Department of Biochemistry, Stanford University School of Medicine, CA 94305-5307, USA.
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Abstract
Dictyostelium amebae have been engineered by homologous recombination of a truncated copy of the myosin heavy chain gene (heavy meromyosin (HMM) cells) and by transformation with a vector encoding an antisense RNA to myosin heavy chain mRNA (mhcA cells) so that they lack native myosin heavy chain protein. In the former case, cells synthesize only the heavy meromyosin portion of the protein and in the latter case they synthesize negligible amounts of the protein. Surprisingly, it was demonstrated that both cell lines are viable and motile. In order to compare the motility of these cells with normal cells, the newly developed computer-assisted Dynamic Morphology System (DMS) was employed. The results demonstrate that the average HMM or mhcA ameba moves at a rate of translocation less than half that of normal cells. It is rounder and less polar than a normal cell, and exhibits a rate of cytoplasmic expansion and contraction roughly half that of normal cells. In a spatial gradient of cAMP, the average ameba of HMM or mhcA exhibits a chemotactic index of +0.10 or less, compared to the chemotactic index of +0.50 exhibited by normal cells. Finally, the initial area, rate of expansion, and final area of pseudopods are roughly half that of normal cells. The five fastest HMM amebae (out of 35 analyzed in detail) moved at an average rate of translocation equal to that of normal amebae, and exhibited an average chemotactic index of +0.34. In addition, the average rate of cytoplasmic flow in fast HMM cells was equal to that of the average normal ameba. However, fast HMM amebae still exhibited the same defects in pseudopod formation that were exhibited by the entire HMM cell population. These results suggest that myosin heavy chain is involved in the "fine tuning" and efficiency of pseudopod formation, but is not essential for the basic behavior of pseudopod expansion.
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Affiliation(s)
- D Wessels
- Department of Biology, University of Iowa, Iowa City 52242
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Peters DJ, Knecht DA, Loomis WF, De Lozanne A, Spudich J, Van Haastert PJ. Signal transduction, chemotaxis, and cell aggregation in Dictyostelium discoideum cells without myosin heavy chain. Dev Biol 1988; 128:158-63. [PMID: 2838347 DOI: 10.1016/0012-1606(88)90278-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dictyostelium discoideum cells have been generated that lack myosin heavy chain (MHC) due to antisense RNA inactivation of the endogenous mRNA or to insertional mutagenesis of the myosin gene. These cells retain chemotactic movement in gradients of the chemoattractant cAMP. Furthermore, cAMP does induce many biochemical and physiological responses in aggregative cells, including binding of cAMP to surface receptors, modification, and down-regulation of the receptor; activation of adenylate and guanylate cyclase, secretion of cAMP; and the association of actin to the Triton-insoluble cytoskeleton. Cells lacking MHC were found to have a requirement for bivalent cations in the medium for optimal chemotaxis and cell aggregation.
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Affiliation(s)
- D J Peters
- Cell Biology and Genetics Unit, University of Leiden, The Netherlands
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