1
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Coscia SM, Moore AS, Thompson CP, Tirrito CF, Ostap EM, Holzbaur ELF. An interphase actin wave promotes mitochondrial content mixing and organelle homeostasis. Nat Commun 2024; 15:3793. [PMID: 38714822 PMCID: PMC11076292 DOI: 10.1038/s41467-024-48189-1] [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: 05/05/2023] [Accepted: 04/22/2024] [Indexed: 05/10/2024] Open
Abstract
Across the cell cycle, mitochondrial dynamics are regulated by a cycling wave of actin polymerization/depolymerization. In metaphase, this wave induces actin comet tails on mitochondria that propel these organelles to drive spatial mixing, resulting in their equitable inheritance by daughter cells. In contrast, during interphase the cycling actin wave promotes localized mitochondrial fission. Here, we identify the F-actin nucleator/elongator FMNL1 as a positive regulator of the wave. FMNL1-depleted cells exhibit decreased mitochondrial polarization, decreased mitochondrial oxygen consumption, and increased production of reactive oxygen species. Accompanying these changes is a loss of hetero-fusion of wave-fragmented mitochondria. Thus, we propose that the interphase actin wave maintains mitochondrial homeostasis by promoting mitochondrial content mixing. Finally, we investigate the mechanistic basis for the observation that the wave drives mitochondrial motility in metaphase but mitochondrial fission in interphase. Our data indicate that when the force of actin polymerization is resisted by mitochondrial tethering to microtubules, as in interphase, fission results.
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Affiliation(s)
- Stephen M Coscia
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Andrew S Moore
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA
| | - Cameron P Thompson
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Christian F Tirrito
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - E Michael Ostap
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Erika L F Holzbaur
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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2
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Xu M, Rutkowski DM, Rebowski G, Boczkowska M, Pollard LW, Dominguez R, Vavylonis D, Ostap EM. Myosin-I Synergizes with Arp2/3 Complex to Enhance Pushing Forces of Branched Actin Networks. bioRxiv 2024:2024.02.09.579714. [PMID: 38405741 PMCID: PMC10888859 DOI: 10.1101/2024.02.09.579714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Myosin-Is colocalize with Arp2/3 complex-nucleated actin networks at sites of membrane protrusion and invagination, but the mechanisms by which myosin-I motor activity coordinates with branched actin assembly to generate force are unknown. We mimicked the interplay of these proteins using the "comet tail" bead motility assay, where branched actin networks are nucleated by Arp2/3 complex on the surface of beads coated with myosin-I and the WCA domain of N-WASP. We observed that myosin-I increased bead movement efficiency by thinning actin networks without affecting growth rates. Remarkably, myosin-I triggered symmetry breaking and comet-tail formation in dense networks resistant to spontaneous fracturing. Even with arrested actin assembly, myosin-I alone could break the network. Computational modeling recapitulated these observations suggesting myosin-I acts as a repulsive force shaping the network's architecture and boosting its force-generating capacity. We propose that myosin-I leverages its power stroke to amplify the forces generated by Arp2/3 complex-nucleated actin networks.
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Affiliation(s)
- Mengqi Xu
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Grzegorz Rebowski
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Malgorzata Boczkowska
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Luther W Pollard
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Roberto Dominguez
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - E Michael Ostap
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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3
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Pedersen RT, Snoberger A, Pyrpassopoulos S, Safer D, Drubin DG, Ostap EM. Endocytic myosin-1 is a force-insensitive, power-generating motor. J Cell Biol 2023; 222:e202303095. [PMID: 37549220 PMCID: PMC10406613 DOI: 10.1083/jcb.202303095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Received: 03/23/2023] [Revised: 05/17/2023] [Accepted: 07/24/2023] [Indexed: 08/09/2023] Open
Abstract
Myosins are required for clathrin-mediated endocytosis, but their precise molecular roles in this process are not known. This is, in part, because the biophysical properties of the relevant motors have not been investigated. Myosins have diverse mechanochemical activities, ranging from powerful contractility against mechanical loads to force-sensitive anchoring. To better understand the essential molecular contribution of myosin to endocytosis, we studied the in vitro force-dependent kinetics of the Saccharomyces cerevisiae endocytic type I myosin called Myo5, a motor whose role in clathrin-mediated endocytosis has been meticulously studied in vivo. We report that Myo5 is a low-duty-ratio motor that is activated ∼10-fold by phosphorylation and that its working stroke and actin-detachment kinetics are relatively force-insensitive. Strikingly, the in vitro mechanochemistry of Myo5 is more like that of cardiac myosin than that of slow anchoring myosin-1s found on endosomal membranes. We, therefore, propose that Myo5 generates power to augment actin assembly-based forces during endocytosis in cells.
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Affiliation(s)
- Ross T.A. Pedersen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Aaron Snoberger
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel Safer
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David G. Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - E. Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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4
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Báez-Cruz FA, Ostap EM. Drosophila class-I myosins that can impact left-right asymmetry have distinct ATPase kinetics. J Biol Chem 2023; 299:104961. [PMID: 37380077 PMCID: PMC10374968 DOI: 10.1016/j.jbc.2023.104961] [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: 05/08/2023] [Revised: 06/13/2023] [Accepted: 06/20/2023] [Indexed: 06/30/2023] Open
Abstract
Myosin-1D (myo1D) is important for Drosophila left-right asymmetry, and its effects are modulated by myosin-1C (myo1C). De novo expression of these myosins in nonchiral Drosophila tissues promotes cell and tissue chirality, with handedness depending on the paralog expressed. Remarkably, the identity of the motor domain determines the direction of organ chirality, rather than the regulatory or tail domains. Myo1D, but not myo1C, propels actin filaments in leftward circles in in vitro experiments, but it is not known if this property contributes to establishing cell and organ chirality. To further explore if there are differences in the mechanochemistry of these motors, we determined the ATPase mechanisms of myo1C and myo1D. We found that myo1D has a 12.5-fold higher actin-activated steady-state ATPase rate, and transient kinetic experiments revealed myo1D has an 8-fold higher MgADP release rate compared to myo1C. Actin-activated phosphate release is rate limiting for myo1C, whereas MgADP release is the rate-limiting step for myo1D. Notably, both myosins have among the tightest MgADP affinities measured for any myosin. Consistent with ATPase kinetics, myo1D propels actin filaments at higher speeds compared to myo1C in in vitro gliding assays. Finally, we tested the ability of both paralogs to transport 50 nm unilamellar vesicles along immobilized actin filaments and found robust transport by myo1D and actin binding but no transport by myo1C. Our findings support a model where myo1C is a slow transporter with long-lived actin attachments, whereas myo1D has kinetic properties associated with a transport motor.
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Affiliation(s)
- Faviolla A Báez-Cruz
- Department of Physiology, and Center for Engineering Mechanobiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - E Michael Ostap
- Department of Physiology, and Center for Engineering Mechanobiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
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Pedersen RTA, Snoberger A, Pyrpassopoulos S, Safer D, Drubin DG, Ostap EM. Endocytic myosin-1 is a force-insensitive, power-generating motor. bioRxiv 2023:2023.03.21.533689. [PMID: 36993306 PMCID: PMC10055380 DOI: 10.1101/2023.03.21.533689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Myosins are required for clathrin-mediated endocytosis, but their precise molecular roles in this process are not known. This is, in part, because the biophysical properties of the relevant motors have not been investigated. Myosins have diverse mechanochemical activities, ranging from powerful contractility against mechanical loads to force-sensitive anchoring. To better understand the essential molecular contribution of myosin to endocytosis, we studied the in vitro force-dependent kinetics of the Saccharomyces cerevisiae endocytic type I myosin called Myo5, a motor whose role in clathrin-mediated endocytosis has been meticulously studied in vivo. We report that Myo5 is a low-duty-ratio motor that is activated ∼10-fold by phosphorylation, and that its working stroke and actin-detachment kinetics are relatively force-insensitive. Strikingly, the in vitro mechanochemistry of Myo5 is more like that of cardiac myosin than like that of slow anchoring myosin-1s found on endosomal membranes. We therefore propose that Myo5 generates power to augment actin assembly-based forces during endocytosis in cells. Summary Pedersen, Snoberger et al. measure the force-sensitivity of the yeast endocytic the myosin-1 called Myo5 and find that it is more likely to generate power than to serve as a force-sensitive anchor in cells. Implications for Myo5's role in clathrin-mediated endocytosis are discussed.
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Affiliation(s)
- Ross TA Pedersen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- Present address: Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
- Equal Contribution
| | - Aaron Snoberger
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Equal Contribution
| | - Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel Safer
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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Coscia SM, Thompson CP, Tang Q, Baltrusaitis EE, Rhodenhiser JA, Quintero-Carmona OA, Ostap EM, Lakadamyali M, Holzbaur ELF. Myo19 tethers mitochondria to endoplasmic reticulum-associated actin to promote mitochondrial fission. J Cell Sci 2023; 136:jcs260612. [PMID: 36744380 PMCID: PMC10022680 DOI: 10.1242/jcs.260612] [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: 09/06/2022] [Accepted: 01/26/2023] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial homeostasis requires a dynamic balance of fission and fusion. The actin cytoskeleton promotes fission, and we found that the mitochondrially localized myosin, myosin 19 (Myo19), is integral to this process. Myo19 knockdown induced mitochondrial elongation, whereas Myo19 overexpression induced fragmentation. This mitochondrial fragmentation was blocked by a Myo19 mutation predicted to inhibit ATPase activity and strong actin binding but not by mutations predicted to affect the working stroke of the motor that preserve ATPase activity. Super-resolution imaging indicated a dispersed localization of Myo19 on mitochondria, which we found to be dependent on metaxins. These observations suggest that Myo19 acts as a dynamic actin-binding tether that facilitates mitochondrial fragmentation. Myo19-driven fragmentation was blocked by depletion of either the CAAX splice variant of the endoplasmic reticulum (ER)-anchored formin INF2 or the mitochondrially localized F-actin nucleator Spire1C (a splice variant of Spire1), which together polymerize actin at sites of mitochondria-ER contact for fission. These observations imply that Myo19 promotes fission by stabilizing mitochondria-ER contacts; we used a split-luciferase system to demonstrate a reduction in these contacts following Myo19 depletion. Our data support a model in which Myo19 tethers mitochondria to ER-associated actin to promote mitochondrial fission.
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Affiliation(s)
- Stephen M. Coscia
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Cameron P. Thompson
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Qing Tang
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Elana E. Baltrusaitis
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | | | | | - E. Michael Ostap
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Melike Lakadamyali
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Erika L. F. Holzbaur
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Xu M, Pollard LW, Rebowski G, Boczkowska M, Dominguez R, Ostap EM. Myosin-I facilitates symmetry breaking and promotes the growth of actin 'comet tails'. Biophys J 2023; 122:167a. [PMID: 36782784 DOI: 10.1016/j.bpj.2022.11.1050] [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)
- Mengqi Xu
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Luther W Pollard
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Grzegorz Rebowski
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Roberto Dominguez
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - E Michael Ostap
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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8
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Pollard LW, Coscia SM, Rebowski G, Palmer NJ, Holzbaur ELF, Dominguez R, Ostap EM. Ensembles of human myosin-19 bound to calmodulin and regulatory light chain RLC12B drive multimicron transport. J Biol Chem 2023; 299:102906. [PMID: 36642185 PMCID: PMC9929473 DOI: 10.1016/j.jbc.2023.102906] [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: 09/26/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/15/2023] Open
Abstract
Myosin-19 (Myo19) controls the size, morphology, and distribution of mitochondria, but the underlying role of Myo19 motor activity is unknown. Complicating mechanistic in vitro studies, the identity of the light chains (LCs) of Myo19 remains unsettled. Here, we show by coimmunoprecipitation, reconstitution, and proteomics that the three IQ motifs of human Myo19 expressed in Expi293 human cells bind regulatory light chain (RLC12B) and calmodulin (CaM). We demonstrate that overexpression of Myo19 in HeLa cells enhances the recruitment of both Myo19 and RLC12B to mitochondria, suggesting cellular association of RLC12B with the motor. Further experiments revealed that RLC12B binds IQ2 and is flanked by two CaM molecules. In vitro, we observed that the maximal speed (∼350 nm/s) occurs when Myo19 is supplemented with CaM, but not RLC12B, suggesting maximal motility requires binding of CaM to IQ-1 and IQ-3. The addition of calcium slowed actin gliding (∼200 nm/s) without an apparent effect on CaM affinity. Furthermore, we show that small ensembles of Myo19 motors attached to quantum dots can undergo processive runs over several microns, and that calcium reduces the attachment frequency and run length of Myo19. Together, our data are consistent with a model where a few single-headed Myo19 molecules attached to a mitochondrion can sustain prolonged motile associations with actin in a CaM- and calcium-dependent manner. Based on these properties, we propose that Myo19 can function in mitochondria transport along actin filaments, tension generation on multiple randomly oriented filaments, and/or pushing against branched actin networks assembled near the membrane surface.
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Affiliation(s)
- Luther W Pollard
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Stephen M Coscia
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Grzegorz Rebowski
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Nicholas J Palmer
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Erika L F Holzbaur
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Roberto Dominguez
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
| | - E Michael Ostap
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
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Pyrpassopoulos S, Gicking AM, Zaniewski TM, Hancock WO, Ostap EM. KIF1A is kinetically tuned to be a superengaging motor under hindering loads. Proc Natl Acad Sci U S A 2023; 120:e2216903120. [PMID: 36598948 PMCID: PMC9926277 DOI: 10.1073/pnas.2216903120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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: 10/03/2022] [Accepted: 11/04/2022] [Indexed: 01/05/2023] Open
Abstract
KIF1A is a highly processive vesicle transport motor in the kinesin-3 family. Mutations in KIF1A lead to neurodegenerative diseases including hereditary spastic paraplegia. We applied optical tweezers to study the ability of KIF1A to generate and sustain force against hindering loads. We used both the three-bead assay, where force is oriented parallel to the microtubule, and the traditional single-bead assay, where force is directed along the radius of the bead, resulting in a vertical force component. The average force and attachment duration of KIF1A in the three-bead assay were substantially greater than those observed in the single-bead assay. Thus, vertical forces accelerate termination of force ramps of KIF1A. Average KIF1A termination forces were slightly lower than the kinesin-1 KIF5B, and the median attachment duration of KIF1A was >10-fold shorter than KIF5B under hindering loads. KIF1A rapidly reengages with microtubules after detachment, as observed previously. Strikingly, quantification enabled by the three-bead assay shows that reengagement largely occurs within 2 ms of detachment, indicating that KIF1A has a nearly 10-fold faster reengagement rate than KIF5B. We found that rapid microtubule reengagement is not due to KIF1A's positively charged loop-12; however, removal of charge from this loop diminished the unloaded run length at near physiological ionic strength. Both loop-12 and the microtubule nucleotide state have modulatory effects on reengagement under load, suggesting a role for the microtubule lattice in KIF1A reengagement. Our results reveal adaptations of KIF1A that lead to a model of superengaging transport under load.
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Affiliation(s)
- Serapion Pyrpassopoulos
- The Pennsylvania Muscle Institute, Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
- Center for Engineering Mechanobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Allison M. Gicking
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
| | - Taylor M. Zaniewski
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
- Department of Chemistry, Pennsylvania State University, University Park, PA16802
| | - William O. Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
- Department of Chemistry, Pennsylvania State University, University Park, PA16802
| | - E. Michael Ostap
- The Pennsylvania Muscle Institute, Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
- Center for Engineering Mechanobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
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10
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Pyrpassopoulos S, Shuman H, Ostap EM. Modulation of Kinesin’s Load-Bearing Capacity by Force Geometry and the Microtubule Track. Biophys J 2022; 121:4748. [DOI: 10.1016/j.bpj.2022.11.2939] [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: 12/05/2022] Open
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11
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Abstract
Myosin modulators are a novel class of pharmaceutical agents that are being developed to treat patients with a range of cardiomyopathies. The therapeutic goal of these drugs is to target cardiac myosins directly to modulate contractility and cardiac power output to alleviate symptoms that lead to heart failure and arrhythmias, without altering calcium signaling. In this Review, we discuss two classes of drugs that have been developed to either activate (omecamtiv mecarbil) or inhibit (mavacamten) cardiac contractility by binding to β-cardiac myosin (MYH7). We discuss progress in understanding the mechanisms by which the drugs alter myosin mechanochemistry, and we provide an appraisal of the results from clinical trials of these drugs, with consideration for the importance of disease heterogeneity and genetic etiology for predicting treatment benefit.
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Affiliation(s)
- Sharlene M Day
- Division of Cardiovascular Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jil C Tardiff
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
| | - E Michael Ostap
- Pennsylvania Muscle Institute and Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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12
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Baez-Cruz FA, Ostap EM. Drosophila MYO-1C and MYO-1D are high duty ratio motors with very high ADP affinity. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1443] [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: 12/01/2022] Open
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13
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Gardini L, Woody MS, Kashchuk AV, Goldman YE, Ostap EM, Capitanio M. High-Speed Optical Traps Address Dynamics of Processive and Non-Processive Molecular Motors. Methods Mol Biol 2022; 2478:513-557. [PMID: 36063333 PMCID: PMC9987584 DOI: 10.1007/978-1-0716-2229-2_19] [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] [Indexed: 11/26/2022]
Abstract
Interactions between biological molecules occur on very different time scales, from the minutes of strong protein-protein bonds, down to below the millisecond duration of rapid biomolecular interactions. Conformational changes occurring on sub-ms time scales and their mechanical force dependence underlie the functioning of enzymes (e.g., motor proteins) that are fundamental for life. However, such rapid interactions are beyond the temporal resolution of most single-molecule methods. We developed ultrafast force-clamp spectroscopy (UFFCS), a single-molecule technique based on laser tweezers that allows us to investigate early and very fast dynamics of a variety of enzymes and their regulation by mechanical load. The technique was developed to investigate the rapid interactions between skeletal muscle myosin and actin, and then applied to the study of different biological systems, from cardiac myosin to processive myosin V, microtubule-binding proteins, transcription factors, and mechanotransducer proteins. Here, we describe two different implementations of UFFCS instrumentation and protocols using either acousto- or electro-optic laser beam deflectors, and their application to the study of processive and non-processive motor proteins.
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Affiliation(s)
- Lucia Gardini
- LENS, European Laboratory for Non-Linear Spectroscopy, Florence, Italy
- National Institute of Optics, National Research Council (INO-CNR), Florence, Italy
| | - Michael S Woody
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Anatolii V Kashchuk
- LENS, European Laboratory for Non-Linear Spectroscopy, Florence, Italy
- Department of Physics and Astronomy, University of Florence, Florence, Italy
| | - Yale E Goldman
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - E Michael Ostap
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Marco Capitanio
- LENS, European Laboratory for Non-Linear Spectroscopy, Florence, Italy.
- Department of Physics and Astronomy, University of Florence, Florence, Italy.
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14
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Masucci EM, Relich PK, Lakadamyali M, Ostap EM, Holzbaur ELF. Microtubule dynamics influence the retrograde biased motility of kinesin-4 motor teams in neuronal dendrites. Mol Biol Cell 2021; 33:ar52. [PMID: 34705476 PMCID: PMC9265162 DOI: 10.1091/mbc.e21-10-0480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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] [Indexed: 11/12/2022] Open
Abstract
Microtubules establish the directionality of intracellular transport by kinesins and dynein through polarized assembly, but it remains unclear how directed transport occurs along microtubules organized with mixed polarity. We investigated the ability of the plus end–directed kinesin-4 motor KIF21B to navigate mixed polarity microtubules in mammalian dendrites. Reconstitution assays with recombinant KIF21B and engineered microtubule bundles or extracted neuronal cytoskeletons indicate that nucleotide-independent microtubule-binding regions of KIF21B modulate microtubule dynamics and promote directional switching on antiparallel microtubules. Optogenetic recruitment of KIF21B to organelles in live neurons induces unidirectional transport in axons but bidirectional transport with a net retrograde bias in dendrites. Removal of the secondary microtubule-binding regions of KIF21B or dampening of microtubule dynamics with low concentrations of nocodazole eliminates retrograde bias in live dendrites. Further exploration of the contribution of microtubule dynamics in dendrites to directionality revealed plus end–out microtubules to be more dynamic than plus end–in microtubules, with nocodazole preferentially stabilizing the plus end–out population. We propose a model in which both nucleotide-sensitive and -insensitive microtubule-binding sites of KIF21B motors contribute to the search and selection of stable plus end–in microtubules within the mixed polarity microtubule arrays characteristic of mammalian dendrites to achieve net retrograde movement of KIF21B-bound cargoes.
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Affiliation(s)
- Erin M Masucci
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Peter K Relich
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Melike Lakadamyali
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - E Michael Ostap
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Erika L F Holzbaur
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
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15
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Masucci EM, Relich PK, Ostap EM, Holzbaur ELF, Lakadamyali M. Cega: a single particle segmentation algorithm to identify moving particles in a noisy system. Mol Biol Cell 2021; 32:931-941. [PMID: 33788586 PMCID: PMC8108521 DOI: 10.1091/mbc.e20-11-0744] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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] [Indexed: 12/01/2022] Open
Abstract
Improvements to particle tracking algorithms are required to effectively analyze the motility of biological molecules in complex or noisy systems. A typical single particle tracking (SPT) algorithm detects particle coordinates for trajectory assembly. However, particle detection filters fail for data sets with low signal-to-noise levels. When tracking molecular motors in complex systems, standard techniques often fail to separate the fluorescent signatures of moving particles from background signal. We developed an approach to analyze the motility of kinesin motor proteins moving along the microtubule cytoskeleton of extracted neurons using the Kullback-Leibler divergence to identify regions where there are significant differences between models of moving particles and background signal. We tested our software on both simulated and experimental data and found a noticeable improvement in SPT capability and a higher identification rate of motors as compared with current methods. This algorithm, called Cega, for “find the object,” produces data amenable to conventional blob detection techniques that can then be used to obtain coordinates for downstream SPT processing. We anticipate that this algorithm will be useful for those interested in tracking moving particles in complex in vitro or in vivo environments.
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Affiliation(s)
- Erin M Masucci
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, University of Pennsylvania, Philadelphia, PA, 19104.,The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Peter K Relich
- Department of Physiology, University of Pennsylvania, Philadelphia, PA, 19104.,The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - E Michael Ostap
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, University of Pennsylvania, Philadelphia, PA, 19104.,The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Erika L F Holzbaur
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, University of Pennsylvania, Philadelphia, PA, 19104.,The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Melike Lakadamyali
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, University of Pennsylvania, Philadelphia, PA, 19104.,The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
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16
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Snoberger A, Barua B, Atherton JL, Shuman H, Forgacs E, Goldman YE, Winkelmann DA, Ostap EM. Myosin with hypertrophic cardiac mutation R712L has a decreased working stroke which is rescued by omecamtiv mecarbil. eLife 2021; 10:63691. [PMID: 33605878 PMCID: PMC7895523 DOI: 10.7554/elife.63691] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 10/02/2020] [Accepted: 01/31/2021] [Indexed: 01/10/2023] Open
Abstract
Hypertrophic cardiomyopathies (HCMs) are the leading cause of acute cardiac failure in young individuals. Over 300 mutations throughout β-cardiac myosin, including in the motor domain, are associated with HCM. A β-cardiac myosin motor mutation (R712L) leads to a severe form of HCM. Actin-gliding motility of R712L-myosin is inhibited, despite near-normal ATPase kinetics. By optical trapping, the working stroke of R712L-myosin was decreased 4-fold, but actin-attachment durations were normal. A prevalent hypothesis that HCM mutants are hypercontractile is thus not universal. R712 is adjacent to the binding site of the heart failure drug omecamtiv mecarbil (OM). OM suppresses the working stroke of normal β-cardiac myosin, but remarkably, OM rescues the R712L-myosin working stroke. Using a flow chamber to interrogate a single molecule during buffer exchange, we found OM rescue to be reversible. Thus, the R712L mutation uncouples lever arm rotation from ATPase activity and this inhibition is rescued by OM.
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Affiliation(s)
- Aaron Snoberger
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Bipasha Barua
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, United States
| | - Jennifer L Atherton
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, United States
| | - Henry Shuman
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Eva Forgacs
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, United States
| | - Yale E Goldman
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Donald A Winkelmann
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, United States
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
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17
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Ji HH, Ostap EM. The regulatory protein 14-3-3β binds to the IQ motifs of myosin-IC independent of phosphorylation. J Biol Chem 2020; 295:3749-3756. [PMID: 31811090 PMCID: PMC7086031 DOI: 10.1074/jbc.ra119.011227] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 10/10/2019] [Revised: 11/21/2019] [Indexed: 12/30/2022] Open
Abstract
Myosin-IC (Myo1c) has been proposed to function in delivery of glucose transporter type 4 (GLUT4)-containing vesicles to the plasma membrane in response to insulin stimulation. Current evidence suggests that, upon insulin stimulation, Myo1c is phosphorylated at Ser701, leading to binding of the signaling protein 14-3-3β. Biochemical and functional details of the Myo1c-14-3-3β interaction have yet to be described. Using recombinantly expressed proteins and mass spectrometry-based analyses to monitor Myo1c phosphorylation, along with pulldown, fluorescence binding, and additional biochemical assays, we show here that 14-3-3β is a dimer and, consistent with previous work, that it binds to Myo1c in the presence of calcium. This interaction was associated with dissociation of calmodulin (CaM) from the IQ motif in Myo1c. Surprisingly, we found that 14-3-3β binds to Myo1c independent of Ser701 phosphorylation in vitro Additionally, in contrast to previous reports, we did not observe Myo1c Ser701 phosphorylation by Ca2+/CaM-dependent protein kinase II (CaMKII), although CaMKII phosphorylated four other Myo1c sites. The presence of 14-3-3β had little effect on the actin-activated ATPase or motile activities of Myo1c. Given these results, it is unlikely that 14-3-3β acts as a cargo adaptor for Myo1c-powered transport; rather, we propose that 14-3-3β binds Myo1c in the presence of calcium and stabilizes the calmodulin-dissociated, nonmotile myosin.
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Affiliation(s)
- Huan-Hong Ji
- Pennsylvania Muscle Institute, Department of Physiology, and Center for Engineering Mechanobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Department of Physiology, and Center for Engineering Mechanobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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18
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Snoberger A, Winkelmann DA, Ostap EM, Goldman YE. Buffer Exchange while Probing a Single Actomyosin Interaction in the Optical Trap. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2445] [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: 10/25/2022] Open
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19
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Pyrpassopoulos S, Shuman H, Ostap EM. Modulation of Kinesin's Load-Bearing Capacity by Force Geometry and the Microtubule Track. Biophys J 2019; 118:243-253. [PMID: 31883614 PMCID: PMC6952184 DOI: 10.1016/j.bpj.2019.10.045] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [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: 08/22/2019] [Revised: 10/03/2019] [Accepted: 10/15/2019] [Indexed: 11/27/2022] Open
Abstract
Kinesin motors and their associated microtubule tracks are essential for long-distance transport of cellular cargos. Intracellular activity and proper recruitment of kinesins is regulated by biochemical signaling, cargo adaptors, microtubule-associated proteins, and mechanical forces. In this study, we found that the effect of opposing forces on the kinesin-microtubule attachment duration depends strongly on experimental assay geometry. Using optical tweezers and the conventional single-bead assay, we show that detachment of kinesin from the microtubule is likely accelerated by forces vertical to the long axis of the microtubule due to contact of the single bead with the underlying microtubule. We used the three-bead assay to minimize the vertical force component and found that when the opposing forces are mainly parallel to the microtubule, the median value of attachment durations between kinesin and microtubules can be up to 10-fold longer than observed using the single-bead assay. Using the three-bead assay, we also found that not all microtubule protofilaments are equivalent interacting substrates for kinesin and that the median value of attachment durations of kinesin varies by more than 10-fold, depending on the relative angular position of the forces along the circumference of the microtubule. Thus, depending on the geometry of forces across the microtubule, kinesin can switch from a fast detaching motor (median attachment duration <0.2 s) to a persistent motor that sustains attachment (median attachment duration >3 s) at high forces (5 pN). Our data show that the load-bearing capacity of the kinesin motor is highly variable and can be dramatically affected by off-axis forces and forces across the microtubule lattice, which has implications for a range of cellular activities, including cell division and organelle transport.
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Affiliation(s)
- Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Department of Physiology, and the Center for Engineering Mechanobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania.
| | - Henry Shuman
- Pennsylvania Muscle Institute, Department of Physiology, and the Center for Engineering Mechanobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Department of Physiology, and the Center for Engineering Mechanobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania.
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20
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Woody MS, Winkelmann DA, Capitanio M, Ostap EM, Goldman YE. Single molecule mechanics resolves the earliest events in force generation by cardiac myosin. eLife 2019; 8:49266. [PMID: 31526481 PMCID: PMC6748826 DOI: 10.7554/elife.49266] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [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: 06/12/2019] [Accepted: 09/03/2019] [Indexed: 12/31/2022] Open
Abstract
Key steps of cardiac mechanochemistry, including the force-generating working stroke and the release of phosphate (Pi), occur rapidly after myosin-actin attachment. An ultra-high-speed optical trap enabled direct observation of the timing and amplitude of the working stroke, which can occur within <200 μs of actin binding by β-cardiac myosin. The initial actomyosin state can sustain loads of at least 4.5 pN and proceeds directly to the stroke or detaches before releasing ATP hydrolysis products. The rates of these processes depend on the force. The time between binding and stroke is unaffected by 10 mM Pi which, along with other findings, indicates the stroke precedes phosphate release. After Pi release, Pi can rebind enabling reversal of the working stroke. Detecting these rapid events under physiological loads provides definitive indication of the dynamics by which actomyosin converts biochemical energy into mechanical work.
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Affiliation(s)
- Michael S Woody
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Donald A Winkelmann
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, United States
| | - Marco Capitanio
- LENS - European Laboratory for Non-linear Spectroscopy, Sesto Fiorentino, Italy.,Department of Physics and Astronomy, University of Florence, Sesto Fiorentino, Italy
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Yale E Goldman
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
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21
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Lebreton G, Géminard C, Lapraz F, Pyrpassopoulos S, Cerezo D, Spéder P, Ostap EM, Noselli S. Molecular to organismal chirality is induced by the conserved myosin 1D. Science 2019; 362:949-952. [PMID: 30467170 DOI: 10.1126/science.aat8642] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 10/04/2018] [Indexed: 11/02/2022]
Abstract
The emergence of asymmetry from an initially symmetrical state is a universal transition in nature. Living organisms show asymmetries at the molecular, cellular, tissular, and organismal level. However, whether and how multilevel asymmetries are related remains unclear. In this study, we show that Drosophila myosin 1D (Myo1D) and myosin 1C (Myo1C) are sufficient to generate de novo directional twisting of cells, single organs, or the whole body in opposite directions. Directionality lies in the myosins' motor domain and is swappable between Myo1D and Myo1C. In addition, Myo1D drives gliding of actin filaments in circular, counterclockwise paths in vitro. Altogether, our results reveal the molecular motor Myo1D as a chiral determinant that is sufficient to break symmetry at all biological scales through chiral interaction with the actin cytoskeleton.
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Affiliation(s)
- G Lebreton
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - C Géminard
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - F Lapraz
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - S Pyrpassopoulos
- Pennsylvania Muscle Institute and the Center for Engineering Mechanobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - D Cerezo
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - P Spéder
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - E M Ostap
- Pennsylvania Muscle Institute and the Center for Engineering Mechanobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - S Noselli
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France.
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22
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Welburn JPI, Ostap EM. Motors in transport and cytoskeleton remodeling. Mol Biol Cell 2019; 30:734. [PMID: 30870091 PMCID: PMC6589778 DOI: 10.1091/mbc.e19-01-0011] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Julie P I Welburn
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - E Michael Ostap
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia PA 19104
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23
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Mentes A, Shuman H, Ostap EM. State Dependent Dynamic Coupling in Myo1B During the Force Sensitive Transition and MgADP Release. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.1415] [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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24
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De La Cruz EM, Blanchoin L, Ostap EM. Opening remarks from the Editors. Biophys Rev 2018; 10:1479-1480. [DOI: 10.1007/s12551-018-0487-3] [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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25
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Woody MS, Greenberg MJ, Barua B, Winkelmann DA, Goldman YE, Ostap EM. Positive cardiac inotrope omecamtiv mecarbil activates muscle despite suppressing the myosin working stroke. Nat Commun 2018; 9:3838. [PMID: 30242219 PMCID: PMC6155018 DOI: 10.1038/s41467-018-06193-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/21/2018] [Indexed: 02/05/2023] Open
Abstract
Omecamtiv mecarbil (OM) is a positive cardiac inotrope in phase-3 clinical trials for treatment of heart failure. Although initially described as a direct myosin activator, subsequent studies are at odds with this description and do not explain OM-mediated increases in cardiac performance. Here we show, via single-molecule, biophysical experiments on cardiac myosin, that OM suppresses myosin's working stroke and prolongs actomyosin attachment 5-fold, which explains inhibitory actions of the drug observed in vitro. OM also causes the actin-detachment rate to become independent of both applied load and ATP concentration. Surprisingly, increased myocardial force output in the presence of OM can be explained by cooperative thin-filament activation by OM-inhibited myosin molecules. Selective suppression of myosin is an unanticipated route to muscle activation that may guide future development of therapeutic drugs.
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Affiliation(s)
- Michael S Woody
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, 700A Clinical Research Building, Philadelphia, PA, 19104-6085, USA
| | - Michael J Greenberg
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, 700A Clinical Research Building, Philadelphia, PA, 19104-6085, USA.,Department of Biochemistry and Molecular Biophysics, Washington University in Saint Louis, St. Louis, 63110, MO, USA
| | - Bipasha Barua
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, 675 Hoes Lane, Piscataway, NJ, 08854, USA
| | - Donald A Winkelmann
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, 675 Hoes Lane, Piscataway, NJ, 08854, USA
| | - Yale E Goldman
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, 700A Clinical Research Building, Philadelphia, PA, 19104-6085, USA.
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, 700A Clinical Research Building, Philadelphia, PA, 19104-6085, USA.
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26
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Woody MS, Capitanio M, Ostap EM, Goldman YE. Electro-optic deflectors deliver advantages over acousto-optical deflectors in a high resolution, ultra-fast force-clamp optical trap. Opt Express 2018; 26:11181-11193. [PMID: 29716042 PMCID: PMC6005679 DOI: 10.1364/oe.26.011181] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/30/2018] [Accepted: 03/30/2018] [Indexed: 06/02/2023]
Abstract
We characterized experimental artifacts arising from the non-linear response of acousto-optical deflectors (AODs) in an ultra-fast force-clamp optical trap and have shown that using electro-optical deflectors (EODs) instead eliminates these artifacts. We give an example of the effects of these artifacts in our ultra-fast force clamp studies of the interaction of myosin with actin filaments. The experimental setup, based on the concept of Capitanio et al. [Nat. Methods 9, 1013-1019 (2012)] utilizes a bead-actin-bead dumbbell held in two force-clamped optical traps which apply a load to the dumbbell to move it at a constant velocity. When myosin binds to actin, the filament motion stops quickly as the total force from the optical traps is transferred to the actomyosin attachment. We found that in our setup, AODs were unsuitable for beam steering due to non-linear variations in beam intensity and deflection angle as a function of driving frequency, likely caused by low-amplitude standing acoustic waves in the deflectors. These aberrations caused instability in the force feedback loops leading to artifactual jumps in the trap position. We demonstrate that beam steering with EODs improves the performance of our instrument. Combining the superior beam-steering capability of the EODs, force acquisition via back-focal-plane interferometry, and dual high-speed FPGA-based feedback loops, we apply precise and constant loads to study the dynamics of interactions between actin and myosin. The same concept applies to studies of other biomolecular interactions.
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Affiliation(s)
- Michael S. Woody
- University of Pennsylvania, Pennsylvania Muscle Institute and Department of Physiology, 415 Curie Blvd, Philadelphia, Pennsylvania, USA 19104
| | - Marco Capitanio
- LENS - European Laboratory for Non-linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
- Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019 Sesto Fiorentino, Italy
| | - E. Michael Ostap
- University of Pennsylvania, Pennsylvania Muscle Institute and Department of Physiology, 415 Curie Blvd, Philadelphia, Pennsylvania, USA 19104
| | - Yale E. Goldman
- University of Pennsylvania, Pennsylvania Muscle Institute and Department of Physiology, 415 Curie Blvd, Philadelphia, Pennsylvania, USA 19104
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27
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Woody MS, Greenberg MJ, Barua B, Winkelmann DA, Goldman YE, Ostap EM. Single Molecule, Optical Trapping Studies of Omecamtiv Mercarbil on Human Cardiac Myosin's Force Production. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.1787] [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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28
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McIntosh BB, Pyrpassopoulos S, Holzbaur ELF, Ostap EM. Opposing Kinesin and Myosin-I Motors Drive Membrane Deformation and Tubulation along Engineered Cytoskeletal Networks. Curr Biol 2018; 28:236-248.e5. [PMID: 29337076 DOI: 10.1016/j.cub.2017.12.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [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: 02/03/2017] [Revised: 09/29/2017] [Accepted: 12/07/2017] [Indexed: 01/22/2023]
Abstract
Microtubule and actin filament molecular motors such as kinesin-1 and myosin-Ic (Myo1c) transport and remodel membrane-bound vesicles; however, it is unclear how they coordinate to accomplish these tasks. We introduced kinesin-1- and Myo1c-bound giant unilamellar vesicles (GUVs) into a micropatterned in vitro cytoskeletal matrix modeled after the subcellular architecture where vesicular sorting and membrane remodeling are observed. This array was composed of sparse microtubules intersecting regions dense with actin filaments, and revealed that Myo1c-dependent tethering of GUVs enabled kinesin-1-driven membrane deformation and tubulation. Membrane remodeling at actin/microtubule intersections was modulated by lipid composition and the addition of the Bin-Amphiphysin-Rvs-domain (BAR-domain) proteins endophilin or FCH-domain-only (FCHo). Myo1c not only tethered microtubule-transported cargo, but also transported, deformed, and tubulated GUVs along actin filaments in a lipid-composition- and BAR-protein-responsive manner. These results suggest a mechanism for actin-based involvement in vesicular transport and remodeling of intracellular membranes, and implicate lipid composition as a key factor in determining whether vesicles will undergo transport, deformation, or tubulation driven by opposing actin and microtubule motors and BAR-domain proteins.
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Affiliation(s)
- Betsy B McIntosh
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA; Center for Engineering MechanoBiology, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Serapion Pyrpassopoulos
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA; Center for Engineering MechanoBiology, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Erika L F Holzbaur
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA; Center for Engineering MechanoBiology, University of Pennsylvania, Philadelphia, PA 19104-6085, USA.
| | - E Michael Ostap
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA; Center for Engineering MechanoBiology, University of Pennsylvania, Philadelphia, PA 19104-6085, USA.
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Pyrpassopoulos S, Shuman H, Ostap EM. Adhesion force and attachment lifetime of the KIF16B-PX domain interaction with lipid membranes. Mol Biol Cell 2017; 28:3315-3322. [PMID: 28931594 PMCID: PMC5687032 DOI: 10.1091/mbc.e17-05-0324] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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: 05/25/2017] [Revised: 08/28/2017] [Accepted: 09/13/2017] [Indexed: 11/21/2022] Open
Abstract
KIF16B is a motor that binds early endosomes and controls the recycling of receptors. It has a PX domain that binds PI(3)P, which has been proposed to mechanically link motor to cargo. We determined the strength of this bond and its lifetime under load, and found it to be a suitable mechanical linkage for the KIF16B motor under working conditions. KIF16B is a highly processive kinesin-3 family member that participates in the trafficking and tubulation of early endosomes along microtubules. KIF16B attaches to lipid cargoes via a PX motif at its C-terminus, which has nanomolar affinity for bilayers containing phosphatidylinositol-3-phosphate (PI[3]P). As the PX domain has been proposed to be a primary mechanical anchor for the KIF16B-cargo attachment, we measured the adhesion forces and detachment kinetics of the PX domain as it interacts with membranes containing 2% PI(3)P and 98% phosphatidylcholine. Using optical tweezers, we found that the adhesion strength of a single PX domain ranged between 19 and 54 pN at loading rates between 80 and 1500 pN/s. These forces are substantially larger than the interaction of the adhesion of a pleckstrin homology domain with phosphatidylinositol 4,5-bisphosphate. This increased adhesion is the result of the membrane insertion of hydrophobic residues adjacent to the PI(3)P binding site, in addition to electrostatic interactions with PI(3)P. Attachment lifetimes under load decrease monotonically with force, indicating slip-bond behavior. However, the lifetime of membrane attachment under load appears to be well matched to the duration of processive motility of the KIF16B motor, indicating the PX domain is a suitable mechanical anchor for intracellular transport.
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Affiliation(s)
- Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Department of Physiology, and Center for Engineering Mechanobiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Henry Shuman
- Pennsylvania Muscle Institute, Department of Physiology, and Center for Engineering Mechanobiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Department of Physiology, and Center for Engineering Mechanobiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
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Woody MS, Lewis JH, Greenberg MJ, Goldman YE, Ostap EM. MEMLET: An Easy-to-Use Tool for Data Fitting and Model Comparison Using Maximum-Likelihood Estimation. Biophys J 2017; 111:273-282. [PMID: 27463130 DOI: 10.1016/j.bpj.2016.06.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 06/06/2016] [Accepted: 06/10/2016] [Indexed: 11/28/2022] Open
Abstract
We present MEMLET (MATLAB-enabled maximum-likelihood estimation tool), a simple-to-use and powerful program for utilizing maximum-likelihood estimation (MLE) for parameter estimation from data produced by single-molecule and other biophysical experiments. The program is written in MATLAB and includes a graphical user interface, making it simple to integrate into the existing workflows of many users without requiring programming knowledge. We give a comparison of MLE and other fitting techniques (e.g., histograms and cumulative frequency distributions), showing how MLE often outperforms other fitting methods. The program includes a variety of features. 1) MEMLET fits probability density functions (PDFs) for many common distributions (exponential, multiexponential, Gaussian, etc.), as well as user-specified PDFs without the need for binning. 2) It can take into account experimental limits on the size of the shortest or longest detectable event (i.e., instrument "dead time") when fitting to PDFs. The proper modification of the PDFs occurs automatically in the program and greatly increases the accuracy of fitting the rates and relative amplitudes in multicomponent exponential fits. 3) MEMLET offers model testing (i.e., single-exponential versus double-exponential) using the log-likelihood ratio technique, which shows whether additional fitting parameters are statistically justifiable. 4) Global fitting can be used to fit data sets from multiple experiments to a common model. 5) Confidence intervals can be determined via bootstrapping utilizing parallel computation to increase performance. Easy-to-follow tutorials show how these features can be used. This program packages all of these techniques into a simple-to-use and well-documented interface to increase the accessibility of MLE fitting.
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Affiliation(s)
- Michael S Woody
- Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - John H Lewis
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael J Greenberg
- Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yale E Goldman
- Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - E Michael Ostap
- Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, Pennsylvania.
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31
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Lewis JH, Jamiolkowski RM, Woody MS, Ostap EM, Goldman YE. Deconvolution of Camera Instrument Response Functions. Biophys J 2017; 112:1214-1220. [PMID: 28355548 DOI: 10.1016/j.bpj.2017.02.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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] [Received: 11/22/2016] [Revised: 02/05/2017] [Accepted: 02/07/2017] [Indexed: 02/03/2023] Open
Abstract
Temporal sequences of fluorescence intensities in single-molecule experiments are often obtained from stacks of camera images. The dwell times of different macromolecular structural or functional states, correlated with characteristic fluorescence intensities, are extracted from the images and combined into dwell time distributions that are fitted by kinetic functions to extract corresponding rate constants. The frame rate of the camera limits the time resolution of the experiment and thus the fastest rate processes that can be reliably detected and quantified. However, including the influence of discrete sampling (framing) on the detected time series in the fitted model enables rate processes near to the frame rate to be reliably estimated. This influence, similar to the instrument response function in other types of instruments, such as pulsed emission decay fluorometers, is easily incorporated into the fitted model. The same concept applies to any temporal data that is low-pass filtered or decimated to improve signal to noise ratio.
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Affiliation(s)
- John H Lewis
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ryan M Jamiolkowski
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael S Woody
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - E Michael Ostap
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yale E Goldman
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
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32
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Mentes A, Shuman H, Ostap EM. Molecular Dynamics and Normal Mode Analysis of Myo1b and Myo1b Deletion Constructs Reveal Coupling between the Lever Arm Helix, N-Terminus, and Active Site. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1441] [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: 10/20/2022] Open
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33
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McIntosh BB, Holzbaur EL, Ostap EM. Myo1C and Endophilin Promote Kinesin-Driven Tubulation at Engineered Cytoskeletal Intersections. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1480] [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: 10/20/2022] Open
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Abstract
The myosin superfamily of molecular motors utilizes energy from ATP hydrolysis to generate force and motility along actin filaments in a diverse array of cellular processes. These motors are structurally, kinetically, and mechanically tuned to their specific molecular roles in the cell. Optical trapping techniques have played a central role in elucidating the mechanisms by which myosins generate force and in exposing the remarkable diversity of myosin functions. Here, we present thorough methods for measuring and analyzing interactions between actin and non-processive myosins using optical trapping techniques.
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Affiliation(s)
- Michael J Greenberg
- Department of Physiology, The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA. .,Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., Campus Box 8231, St. Louis, MO, 63110, USA.
| | - Henry Shuman
- Department of Physiology, The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - E Michael Ostap
- Department of Physiology, The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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35
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Ghiretti AE, Thies E, Tokito MK, Lin T, Ostap EM, Kneussel M, Holzbaur ELF. Activity-Dependent Regulation of Distinct Transport and Cytoskeletal Remodeling Functions of the Dendritic Kinesin KIF21B. Neuron 2016; 92:857-872. [PMID: 27817978 DOI: 10.1016/j.neuron.2016.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [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: 04/19/2016] [Revised: 08/05/2016] [Accepted: 09/20/2016] [Indexed: 01/19/2023]
Abstract
The dendritic arbor is subject to continual activity-dependent remodeling, requiring a balance between directed cargo trafficking and dynamic restructuring of the underlying microtubule tracks. How cytoskeletal components are able to dynamically regulate these processes to maintain this balance remains largely unknown. By combining single-molecule assays and live imaging in rat hippocampal neurons, we have identified the kinesin-4 KIF21B as a molecular regulator of activity-dependent trafficking and microtubule dynamicity in dendrites. We find that KIF21B contributes to the retrograde trafficking of brain-derived neurotrophic factor (BDNF)-TrkB complexes and also regulates microtubule dynamics through a separable, non-motor microtubule-binding domain. Neuronal activity enhances the motility of KIF21B at the expense of its role in cytoskeletal remodeling, the first example of a kinesin whose function is directly tuned to neuronal activity state. These studies suggest a model in which KIF21B navigates the complex cytoskeletal environment of dendrites by compartmentalizing functions in an activity-dependent manner.
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Affiliation(s)
- Amy E Ghiretti
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Edda Thies
- Department of Molecular Neurogenetics, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany
| | - Mariko K Tokito
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Tianming Lin
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA
| | - E Michael Ostap
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Matthias Kneussel
- Department of Molecular Neurogenetics, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA.
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36
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Abstract
Myosin-I molecular motors are proposed to play various cellular roles related to membrane dynamics and trafficking. In this Cell Science at a Glance article and the accompanying poster, we review and illustrate the proposed cellular functions of metazoan myosin-I molecular motors by examining the structural, biochemical, mechanical and cell biological evidence for their proposed molecular roles. We highlight evidence for the roles of myosin-I isoforms in regulating membrane tension and actin architecture, powering plasma membrane and organelle deformation, participating in membrane trafficking, and functioning as a tension-sensitive dock or tether. Collectively, myosin-I motors have been implicated in increasingly complex cellular phenomena, yet how a single isoform accomplishes multiple types of molecular functions is still an active area of investigation. To fully understand the underlying physiology, it is now essential to piece together different approaches of biological investigation. This article will appeal to investigators who study immunology, metabolic diseases, endosomal trafficking, cell motility, cancer and kidney disease, and to those who are interested in how cellular membranes are coupled to the underlying actin cytoskeleton in a variety of different applications.
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Affiliation(s)
- Betsy B McIntosh
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - E Michael Ostap
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
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37
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Greenberg MJ, Arpağ G, Tüzel E, Ostap EM. A Perspective on the Role of Myosins as Mechanosensors. Biophys J 2016; 110:2568-2576. [PMID: 27332116 PMCID: PMC4919425 DOI: 10.1016/j.bpj.2016.05.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [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] [Received: 12/30/2015] [Revised: 04/13/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022] Open
Abstract
Cells are dynamic systems that generate and respond to forces over a range of spatial and temporal scales, spanning from single molecules to tissues. Substantial progress has been made in recent years in identifying the molecules and pathways responsible for sensing and transducing mechanical signals to short-term cellular responses and longer-term changes in gene expression, cell identity, and tissue development. In this perspective article, we focus on myosin motors, as they not only function as the primary force generators in well-studied mechanobiological processes, but also act as key mechanosensors in diverse functions including intracellular transport, signaling, cell migration, muscle contraction, and sensory perception. We discuss how the biochemical and mechanical properties of different myosin isoforms are tuned to fulfill these roles in an array of cellular processes, and we highlight the underappreciated diversity of mechanosensing properties within the myosin superfamily. In particular, we use modeling and simulations to make predictions regarding how diversity in force sensing affects the lifetime of the actomyosin bond, the myosin power output, and the ability of myosin to respond to a perturbation in force for several nonprocessive myosin isoforms.
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Affiliation(s)
- Michael J Greenberg
- Biochemistry and Molecular Biophysics, Washington University, St. Louis, Missouri
| | - Göker Arpağ
- Worcester Polytechnic Institute, Worcester, Massachusetts
| | - Erkan Tüzel
- Worcester Polytechnic Institute, Worcester, Massachusetts
| | - E Michael Ostap
- Pennsylvania Muscle Institute and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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38
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Greenberg MJ, Shuman H, Ostap EM. Inherent force-dependent properties of β-cardiac myosin contribute to the force-velocity relationship of cardiac muscle. Biophys J 2016; 107:L41-L44. [PMID: 25517169 DOI: 10.1016/j.bpj.2014.11.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 01/14/2023] Open
Abstract
The heart adjusts its power output to meet specific physiological needs through the coordination of several mechanisms, including force-induced changes in contractility of the molecular motor, the β-cardiac myosin (βCM). Despite its importance in driving and regulating cardiac power output, the effect of force on the contractility of a single βCM has not been measured. Using single molecule optical-trapping techniques, we found that βCM has a two-step working stroke. Forces that resist the power stroke slow the myosin-driven contraction by slowing the rate of ADP release, which is the kinetic step that limits fiber shortening. The kinetic properties of βCM are affected by load, suggesting that the properties of myosin contribute to the force-velocity relationship in intact muscle and play an important role in the regulation of cardiac power output.
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Affiliation(s)
- Michael J Greenberg
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Henry Shuman
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - E Michael Ostap
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
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39
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Kee AJ, Yang L, Lucas CA, Greenberg MJ, Martel N, Leong GM, Hughes WE, Cooney GJ, James DE, Ostap EM, Han W, Gunning PW, Hardeman EC. An Actin Filament Population Defined by the Tropomyosin Tpm3.1 Regulates Glucose Uptake. Traffic 2016; 17:80-1. [PMID: 26688443 DOI: 10.1111/tra.12342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anthony J Kee
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
| | - Lingyan Yang
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
| | - Christine A Lucas
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
| | - Michael J Greenberg
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Nick Martel
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Gary M Leong
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia.,Department of Paediatric Endocrinology and Diabetes, Mater Children's Hospital, South Brisbane, QLD 4010, Australia
| | - William E Hughes
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Gregory J Cooney
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - David E James
- Charles Perkins Centre, School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
| | - E Michael Ostap
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Weiping Han
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, 138667, Singapore
| | - Peter W Gunning
- Oncology Research Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
| | - Edna C Hardeman
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
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40
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Woody MS, Lewis JH, Greenberg MJ, Goldman YE, Ostap EM. Accessible, Feature-Rich Software for Rigorous Model Fitting using Maximum Likelihood Estimation. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.1778] [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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41
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Pyrpassopoulos S, Arpag G, Feeser EA, Shuman H, Tuzel E, Ostap EM. Force Generation by Membrane-Associated Myosin-I. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.2499] [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: 11/16/2022] Open
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42
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Kee AJ, Yang L, Lucas CA, Greenberg MJ, Martel N, Leong GM, Hughes WE, Cooney GJ, James DE, Ostap EM, Han W, Gunning PW, Hardeman EC. An actin filament population defined by the tropomyosin Tpm3.1 regulates glucose uptake. Traffic 2015; 16:691-711. [PMID: 25783006 PMCID: PMC4945106 DOI: 10.1111/tra.12282] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [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: 08/10/2014] [Revised: 03/10/2015] [Accepted: 03/11/2015] [Indexed: 12/21/2022]
Abstract
Actin has an ill-defined role in the trafficking of GLUT4 glucose transporter vesicles to the plasma membrane (PM). We have identified novel actin filaments defined by the tropomyosin Tpm3.1 at glucose uptake sites in white adipose tissue (WAT) and skeletal muscle. In Tpm 3.1-overexpressing mice, insulin-stimulated glucose uptake was increased; while Tpm3.1-null mice they were more sensitive to the impact of high-fat diet on glucose uptake. Inhibition of Tpm3.1 function in 3T3-L1 adipocytes abrogates insulin-stimulated GLUT4 translocation and glucose uptake. In WAT, the amount of filamentous actin is determined by Tpm3.1 levels and is paralleled by changes in exocyst component (sec8) and Myo1c levels. In adipocytes, Tpm3.1 localizes with MyoIIA, but not Myo1c, and it inhibits Myo1c binding to actin. We propose that Tpm3.1 determines the amount of cortical actin that can engage MyoIIA and generate contractile force, and in parallel limits the interaction of Myo1c with actin filaments. The balance between these actin filament populations may determine the efficiency of movement and/or fusion of GLUT4 vesicles with the PM.
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Affiliation(s)
- Anthony J. Kee
- Cellular and Genetic Medicine UnitSchool of Medical Sciences, UNSW AustraliaSydneyNSW2052Australia
| | - Lingyan Yang
- Cellular and Genetic Medicine UnitSchool of Medical Sciences, UNSW AustraliaSydneyNSW2052Australia
| | - Christine A. Lucas
- Cellular and Genetic Medicine UnitSchool of Medical Sciences, UNSW AustraliaSydneyNSW2052Australia
| | - Michael J. Greenberg
- The Pennsylvania Muscle Institute and Department of PhysiologyPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPA19104‐6085USA
| | - Nick Martel
- Obesity Research Centre, Institute for Molecular BioscienceThe University of QueenslandSt LuciaQLD4072Australia
| | - Gary M. Leong
- Obesity Research Centre, Institute for Molecular BioscienceThe University of QueenslandSt LuciaQLD4072Australia
- Department of Paediatric Endocrinology and DiabetesMater Children's HospitalSouth BrisbaneQLD4010Australia
| | - William E. Hughes
- Diabetes and Obesity ProgramGarvan Institute of Medical ResearchSydneyNSW2010Australia
| | - Gregory J. Cooney
- Diabetes and Obesity ProgramGarvan Institute of Medical ResearchSydneyNSW2010Australia
| | - David E. James
- Charles Perkins Centre, School of Molecular BioscienceUniversity of SydneySydneyNSW2006Australia
| | - E. Michael Ostap
- The Pennsylvania Muscle Institute and Department of PhysiologyPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPA19104‐6085USA
| | - Weiping Han
- Singapore Bioimaging ConsortiumAgency for Science, Technology and Research (A*STAR)Singapore138667Singapore
| | - Peter W. Gunning
- Oncology Research UnitSchool of Medical Sciences, UNSW AustraliaSydneyNSW2052Australia
| | - Edna C. Hardeman
- Cellular and Genetic Medicine UnitSchool of Medical Sciences, UNSW AustraliaSydneyNSW2052Australia
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43
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Kast DJ, Zajac AL, Holzbaur ELF, Ostap EM, Dominguez R. WHAMM Directs the Arp2/3 Complex to the ER for Autophagosome Biogenesis through an Actin Comet Tail Mechanism. Curr Biol 2015; 25:1791-7. [PMID: 26096974 PMCID: PMC4489997 DOI: 10.1016/j.cub.2015.05.042] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [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] [Received: 01/13/2015] [Revised: 04/20/2015] [Accepted: 05/21/2015] [Indexed: 11/21/2022]
Abstract
Nucleation-promoting factors (NPFs) control the spatio-temporal activity of Arp2/3 complex in cells]. Thus, WASP and the WAVE complex direct the formation of branched actin networks at the leading edge during cell motility and endo/exocytosis, whereas the WASH complex is involved in endosomal transport. Less understood are WHAMM and JMY, two NPFs with similar domain architecture. JMY is found in the nucleus and the cytosol and is involved in transcriptional regulation, cell motility, and trans-Golgi transport. WHAMM was reported to bind microtubules and to be involved in ER to cis-Golgi transport. Here, we show that WHAMM directs the activity of Arp2/3 complex for autophagosome biogenesis through an actin-comet tail motility mechanism. Macroautophagy--the process by which cytosolic material is engulfed into autophagosomes for degradation and/or recycling--was recently shown to involve actin, but the mechanism is unknown. We found that WHAMM forms puncta that colocalize and comigrate with the autophagy markers LC3, DFCP1, and p62 through a WHAMM-dependent actin-comet tail mechanism. Under starvation, WHAMM and actin are observed at the interface between neighboring autophagosomes, whose number and size increase with WHAMM expression. Interfering with actin polymerization, inhibiting Arp2/3 complex, knocking down WHAMM, or blocking its interaction with Arp2/3 complex through mutagenesis all inhibit comet tail formation and reduce the size and number of autophagosomes. Finally, JMY shows similar localization to WHAMM and could be involved in similar processes. These results reveal a link between Arp2/3-complex-dependent actin assembly and autophagy.
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Affiliation(s)
- David J Kast
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Allison L Zajac
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - E Michael Ostap
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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44
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McIntosh BB, Holzbaur ELF, Ostap EM. Control of the initiation and termination of kinesin-1-driven transport by myosin-Ic and nonmuscle tropomyosin. Curr Biol 2015; 25:523-9. [PMID: 25660542 DOI: 10.1016/j.cub.2014.12.008] [Citation(s) in RCA: 21] [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] [Received: 09/15/2014] [Revised: 11/14/2014] [Accepted: 12/02/2014] [Indexed: 10/24/2022]
Abstract
Intracellular transport is largely driven by processive microtubule- and actin-based molecular motors. Nonprocessive motors have also been localized to trafficking cargos, but their roles are not well understood. Myosin-Ic (Myo1c), a nonprocessive actin motor, functions in a variety of exocytic events, although the underlying mechanisms are not yet clear. To investigate the interplay between myosin-I and the canonical long-distance transport motor kinesin-1, we attached both motor types to lipid membrane-coated bead cargo, using an attachment strategy that allows motors to actively reorganize within the membrane in response to the local cytoskeletal environment. We compared the motility of kinesin-1-driven cargos in the absence and presence of Myo1c at engineered actin/microtubule intersections. We found that Myo1c significantly increases the frequency of kinesin-1-driven microtubule-based runs that begin at actin/microtubule intersections. Myo1c also regulates the termination of processive runs. Beads with both motors bound have a significantly higher probability of pausing at actin/microtubule intersections, remaining tethered for an average of 20 s, with some pauses lasting longer than 200 s. The actin-binding protein nonmuscle tropomyosin (Tm) provides spatially specific regulation of interactions between myosin motors and actin filaments in vivo; in the crossed-filament in vitro assay, we found that Tm2-actin abolishes Myo1c-specific effects on both run initiation and run termination. Together, these observations suggest Myo1c is important for the selective initiation and termination of kinesin-1-driven runs along microtubules at specific actin filament populations within the cell.
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Affiliation(s)
- Betsy B McIntosh
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Erika L F Holzbaur
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA.
| | - E Michael Ostap
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA.
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Greenberg MJ, Lin T, Shuman H, Ostap EM. Structural Determinants of Myosin I Mechanosensing: The N Terminal Region. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.162] [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: 10/24/2022] Open
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McIntosh BB, Holzbaur EL, Ostap EM. Control of the Initiation and Termination of Kinesin-1-Driven Transport by Myosin-Ic and Non-Muscle Tropomyosin. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.3255] [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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Ayloo S, Lazarus JE, Dodda A, Tokito M, Ostap EM, Holzbaur ELF. Dynactin functions as both a dynamic tether and brake during dynein-driven motility. Nat Commun 2014; 5:4807. [PMID: 25185702 DOI: 10.1038/ncomms5807] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/24/2014] [Indexed: 01/27/2023] Open
Abstract
Dynactin is an essential cofactor for most cellular functions of the microtubule motor cytoplasmic dynein, but the mechanism by which dynactin activates dynein remains unclear. Here we use single molecule approaches to investigate dynein regulation by the dynactin subunit p150(Glued). We investigate the formation and motility of a dynein-p150(Glued) co-complex using dual-colour total internal reflection fluorescence microscopy. p150(Glued) recruits and tethers dynein to the microtubule in a concentration-dependent manner. Single molecule imaging of motility in cell extracts demonstrates that the CAP-Gly domain of p150(Glued) decreases the detachment rate of the dynein-dynactin complex from the microtubule and also acts as a brake to slow the dynein motor. Consistent with this important role, two neurodegenerative disease-causing mutations in the CAP-Gly domain abrogate these functions in our assays. Together, these observations support a model in which dynactin enhances the initial recruitment of dynein onto microtubules and promotes the sustained engagement of dynein with its cytoskeletal track.
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Affiliation(s)
- Swathi Ayloo
- 1] Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA [2] Department of Biology Graduate Group, School of Arts and Sciences at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA
| | - Jacob E Lazarus
- Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA
| | - Aditya Dodda
- Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01008, USA
| | - Mariko Tokito
- Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA
| | - E Michael Ostap
- Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA
| | - Erika L F Holzbaur
- Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA
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Greenberg MJ, Shuman H, Zwolak A, Sindelar C, Dominguez R, Ostap EM. The Structure of Vertebrate Myosin-I Reveals New Insights into Mechanochemical Tuning of Myosins. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.1006] [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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Zajac AL, Goldman YE, Holzbaur ELF, Ostap EM. Local cytoskeletal and organelle interactions impact molecular-motor- driven early endosomal trafficking. Curr Biol 2013; 23:1173-80. [PMID: 23770188 DOI: 10.1016/j.cub.2013.05.015] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/11/2013] [Accepted: 05/09/2013] [Indexed: 11/26/2022]
Abstract
BACKGROUND In the intracellular environment, motor-driven cargo must navigate a dense cytoskeletal network among abundant organelles. RESULTS We investigated the effects of the crowded intracellular environment on early endosomal trafficking. Live-cell imaging of an endosomal cargo (endocytosed epidermal growth factor-conjugated quantum dots) combined with high-resolution tracking was used to analyze the heterogeneous motion of individual endosomes. The motile population of endosomes moved toward the perinuclear region in directed bursts of microtubule-based, dynein-dependent transport interrupted by longer periods of diffusive motion. Actin network density did not affect motile endosomes during directed runs or diffusive interruptions. Simultaneous two-color imaging was used to correlate changes in endosomal movement with potential obstacles to directed runs. Termination of directed runs spatially correlated with microtubule-dense regions, encounters with other endosomes, and interactions with the endoplasmic reticulum. During a subset of run terminations, we also observed merging and splitting of endosomes, deformation of the endoplasmic reticulum, and directional reversals at speeds up to 10-fold greater than characteristic in vitro motor velocities. These observations suggest that endosomal membrane tension is high during directed run termination. CONCLUSIONS Our results indicate that the crowded cellular environment significantly impacts the motor-driven motility of organelles. Rather than simply acting as impediments to movement, interactions of trafficking cargos with intracellular obstacles may facilitate communication between membrane-bound compartments or contribute to the generation of membrane tension necessary for fusion and fission of endosomal membranes or remodeling of the endoplasmic reticulum.
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Affiliation(s)
- Allison L Zajac
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
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Ostap EM, Greenberg MJ, Laakso JM, Goldman YE, Shuman H. From force‐sensing to power generation – How force modulates the ATPase kinetics of myosin motors. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.454.3] [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)
- E Michael Ostap
- Pennsylvania Muscle InstituteUniversity of PennsylvaniaPhiladelphiaPA
| | | | - Joseph M Laakso
- Pennsylvania Muscle InstituteUniversity of PennsylvaniaPhiladelphiaPA
| | - Yale E Goldman
- Pennsylvania Muscle InstituteUniversity of PennsylvaniaPhiladelphiaPA
| | - Henry Shuman
- Pennsylvania Muscle InstituteUniversity of PennsylvaniaPhiladelphiaPA
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