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Leidel C, Longoria RA, Gutierrez FM, Shubeita GT. Measuring molecular motor forces in vivo: implications for tug-of-war models of bidirectional transport. Biophys J 2013; 103:492-500. [PMID: 22947865 DOI: 10.1016/j.bpj.2012.06.038] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 06/03/2012] [Accepted: 06/20/2012] [Indexed: 12/27/2022] Open
Abstract
Molecular motor proteins use the energy released from ATP hydrolysis to generate force and haul cargoes along cytoskeletal filaments. Thus, measuring the force motors generate amounts to directly probing their function. We report on optical trapping methodology capable of making precise in vivo stall-force measurements of individual cargoes hauled by molecular motors in their native environment. Despite routine measurement of motor forces in vitro, performing and calibrating such measurements in vivo has been challenging. We describe the methodology recently developed to overcome these difficulties, and used to measure stall forces of both kinesin-1 and cytoplasmic dynein-driven lipid droplets in Drosophila embryos. Critically, by measuring the cargo dynamics in the optical trap, we find that there is memory: it is more likely for a cargo to resume motion in the same direction-rather than reverse direction-after the motors transporting it detach from the microtubule under the force of the optical trap. This suggests that only motors of one polarity are active on the cargo at any instant in time and is not consistent with the tug-of-war models of bidirectional transport where both polarity motors can bind the microtubules at all times. We further use the optical trap to measure in vivo the detachment rates from microtubules of kinesin-1 and dynein-driven lipid droplets. Unlike what is commonly assumed, we find that dynein's but not kinesin's detachment time in vivo increases with opposing load. This suggests that dynein's interaction with microtubules behaves like a catch bond.
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Affiliation(s)
- Christina Leidel
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas
| | - Rafael A Longoria
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas
| | - Franciso Marquez Gutierrez
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas
| | - George T Shubeita
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas.
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Zou Z, Du D, Wang J, Smith JN, Timchalk C, Li Y, Lin Y. Quantum Dot-Based Immunochromatographic Fluorescent Biosensor for Biomonitoring Trichloropyridinol, a Biomarker of Exposure to Chlorpyrifos. Anal Chem 2010; 82:5125-33. [DOI: 10.1021/ac100260m] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Zhexiang Zou
- Department of Chemistry and Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China, and Pacific Northwest National Laboratory, Richland, Washington 99352, and College of Chemistry, Central China Normal University, Wuhan 430039 China
| | - Dan Du
- Department of Chemistry and Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China, and Pacific Northwest National Laboratory, Richland, Washington 99352, and College of Chemistry, Central China Normal University, Wuhan 430039 China
| | - Jun Wang
- Department of Chemistry and Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China, and Pacific Northwest National Laboratory, Richland, Washington 99352, and College of Chemistry, Central China Normal University, Wuhan 430039 China
| | - Jordan N. Smith
- Department of Chemistry and Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China, and Pacific Northwest National Laboratory, Richland, Washington 99352, and College of Chemistry, Central China Normal University, Wuhan 430039 China
| | - Charles Timchalk
- Department of Chemistry and Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China, and Pacific Northwest National Laboratory, Richland, Washington 99352, and College of Chemistry, Central China Normal University, Wuhan 430039 China
| | - Yaoqun Li
- Department of Chemistry and Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China, and Pacific Northwest National Laboratory, Richland, Washington 99352, and College of Chemistry, Central China Normal University, Wuhan 430039 China
| | - Yuehe Lin
- Department of Chemistry and Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China, and Pacific Northwest National Laboratory, Richland, Washington 99352, and College of Chemistry, Central China Normal University, Wuhan 430039 China
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Dange T, Grünwald D, Grünwald A, Peters R, Kubitscheck U. Autonomy and robustness of translocation through the nuclear pore complex: a single-molecule study. ACTA ACUST UNITED AC 2008; 183:77-86. [PMID: 18824568 PMCID: PMC2557044 DOI: 10.1083/jcb.200806173] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
All molecular traffic between nucleus and cytoplasm occurs via the nuclear pore complex (NPC) within the nuclear envelope. In this study we analyzed the interactions of the nuclear transport receptors kapα2, kapβ1, kapβ1ΔN44, and kapβ2, and the model transport substrate, BSA-NLS, with NPCs to determine binding sites and kinetics using single-molecule microscopy in living cells. Recombinant transport receptors and BSA-NLS were fluorescently labeled by AlexaFluor 488, and microinjected into the cytoplasm of living HeLa cells expressing POM121-GFP as a nuclear pore marker. After bleaching the dominant GFP fluorescence the interactions of the microinjected molecules could be studied using video microscopy with a time resolution of 5 ms, achieving a colocalization precision of 30 nm. These measurements allowed defining the interaction sites with the NPCs with an unprecedented precision, and the comparison of the interaction kinetics with previous in vitro measurements revealed new insights into the translocation mechanism.
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Affiliation(s)
- Thomas Dange
- Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, D-53115 Bonn, Germany
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Ishii Y, Taniguchi Y, Iwaki M, Yanagida T. Thermal fluctuations biased for directional motion in molecular motors. Biosystems 2008; 93:34-8. [DOI: 10.1016/j.biosystems.2008.04.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 04/21/2008] [Accepted: 04/21/2008] [Indexed: 11/28/2022]
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