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Nagpal S, Swaminathan K, Beaudet D, Verdier M, Wang S, Berger CL, Berger F, Hendricks AG. Optogenetic control of kinesin-1, -2, -3 and dynein reveals their specific roles in vesicular transport. Cell Rep 2024; 43:114649. [PMID: 39159044 DOI: 10.1016/j.celrep.2024.114649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/04/2024] [Accepted: 08/01/2024] [Indexed: 08/21/2024] Open
Abstract
Each cargo in a cell employs a unique set of motor proteins for its transport. To dissect the roles of each type of motor, we developed optogenetic inhibitors of endogenous kinesin-1, -2, -3 and dynein motors and examined their effect on the transport of early endosomes, late endosomes, and lysosomes. While kinesin-1, -3, and dynein transport vesicles at all stages of endocytosis, kinesin-2 primarily drives late endosomes and lysosomes. Transient optogenetic inhibition of kinesin-1 or dynein causes both early and late endosomes to move more processively by relieving competition with opposing motors. Kinesin-2 and -3 support long-range transport, and optogenetic inhibition reduces the distances that their cargoes move. These results suggest that the directionality of transport is controlled through regulating kinesin-1 and dynein activity. On vesicles transported by several kinesin and dynein motors, modulating the activity of a single type of motor on the cargo is sufficient to direct motility.
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Affiliation(s)
- Sahil Nagpal
- Department of Bioengineering, McGill University, Montreal, QC H3A 0E9, Canada
| | | | - Daniel Beaudet
- Department of Bioengineering, McGill University, Montreal, QC H3A 0E9, Canada
| | - Maud Verdier
- Department of Bioengineering, McGill University, Montreal, QC H3A 0E9, Canada; Department of Biomedical Engineering and Health, Episen, Université Paris-Est Créteil, 94010 Créteil Cedex, France
| | - Samuel Wang
- Department of Bioengineering, McGill University, Montreal, QC H3A 0E9, Canada
| | - Christopher L Berger
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405-0075, USA
| | - Florian Berger
- Cell Biology, Neurobiology, and Biophysics, Department of Biology, Utrecht University, Utrecht, the Netherlands
| | - Adam G Hendricks
- Department of Bioengineering, McGill University, Montreal, QC H3A 0E9, Canada.
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2
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Williquett J, Allamargot C, Sun H. AMPK-SP1-Guided Dynein Expression Represents a New Energy-Responsive Mechanism and Therapeutic Target for Diabetic Nephropathy. KIDNEY360 2024; 5:538-549. [PMID: 38467599 PMCID: PMC11093544 DOI: 10.34067/kid.0000000000000392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/05/2024] [Indexed: 03/13/2024]
Abstract
Key Points AMP kinase senses diabetic stresses in podocytes, subsequently upregulates specificity protein 1–mediated dynein expression and promotes podocyte injury. Pharmaceutical restoration of dynein expression by targeting specificity protein 1 represents an innovative therapeutic strategy for diabetic nephropathy. Background Diabetic nephropathy (DN) is a major complication of diabetes. Injury to podocytes, epithelial cells that form the molecular sieve of a kidney, is a preclinical feature of DN. Protein trafficking mediated by dynein, a motor protein complex, is a newly recognized pathophysiology of diabetic podocytopathy and is believed to be derived from the hyperglycemia-induced expression of subunits crucial for the transportation activity of the dynein complex. However, the mechanism underlying this transcriptional signature remains unknown. Methods Through promoter analysis, we identified binding sites for transcription factor specificity protein 1 (SP1) as the most shared motif among hyperglycemia-responsive dynein genes. We demonstrated the essential role of AMP-activated protein kinase (AMPK)–regulated SP1 in the transcription of dynein subunits and dynein-mediated trafficking in diabetic podocytopathy using chromatin immunoprecipitation quantitative PCR and live cell imaging. SP1-dependent dynein-driven pathogenesis of diabetic podocytopathy was demonstrated by pharmaceutical intervention with SP1 in a mouse model of streptozotocin-induced diabetes. Results Hyperglycemic conditions enhance SP1 binding to dynein promoters, promoted dynein expression, and enhanced dynein-mediated mistrafficking in cultured podocytes. These changes can be rescued by chemical inhibition or genetic silencing of SP1. The direct repression of AMPK, an energy sensor, replicates hyperglycemia-induced dynein expression by activating SP1. Mithramycin inhibition of SP1-directed dynein expression in streptozotocin-induced diabetic mice protected them from developing podocytopathy and prevented DN progression. Conclusions Our work implicates AMPK-SP1–regulated dynein expression as an early mechanism that translates energy disturbances in diabetes into podocyte dysfunction. Pharmaceutical restoration of dynein expression by targeting SP1 offers a new therapeutic strategy to prevent DN.
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Affiliation(s)
- Jillian Williquett
- Division of Nephrology, Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
- Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Chantal Allamargot
- Central Microscopy Research Facility, The University of Iowa, Iowa City, Iowa
| | - Hua Sun
- Division of Nephrology, Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
- Carver College of Medicine, The University of Iowa, Iowa City, Iowa
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3
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D'Souza AI, Grover R, Monzon GA, Santen L, Diez S. Vesicles driven by dynein and kinesin exhibit directional reversals without regulators. Nat Commun 2023; 14:7532. [PMID: 37985763 PMCID: PMC10662051 DOI: 10.1038/s41467-023-42605-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 10/16/2023] [Indexed: 11/22/2023] Open
Abstract
Intracellular vesicular transport along cytoskeletal filaments ensures targeted cargo delivery. Such transport is rarely unidirectional but rather bidirectional, with frequent directional reversals owing to the simultaneous presence of opposite-polarity motors. So far, it has been unclear whether such complex motility pattern results from the sole mechanical interplay between opposite-polarity motors or requires regulators. Here, we demonstrate that a minimal system, comprising purified Dynein-Dynactin-BICD2 (DDB) and kinesin-3 (KIF16B) attached to large unilamellar vesicles, faithfully reproduces in vivo cargo motility, including runs, pauses, and reversals. Remarkably, opposing motors do not affect vesicle velocity during runs. Our computational model reveals that the engagement of a small number of motors is pivotal for transitioning between runs and pauses. Taken together, our results suggest that motors bound to vesicular cargo transiently engage in a tug-of-war during pauses. Subsequently, stochastic motor attachment and detachment events can lead to directional reversals without the need for regulators.
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Affiliation(s)
- Ashwin I D'Souza
- B CUBE - Center for Molecular Bioengineering, TU Dresden, Dresden, Germany
| | - Rahul Grover
- B CUBE - Center for Molecular Bioengineering, TU Dresden, Dresden, Germany
| | - Gina A Monzon
- B CUBE - Center for Molecular Bioengineering, TU Dresden, Dresden, Germany
- Center for Biophysics, Department of Physics, Saarland University, Saarbrücken, Germany
| | - Ludger Santen
- Center for Biophysics, Department of Physics, Saarland University, Saarbrücken, Germany.
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, TU Dresden, Dresden, Germany.
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany.
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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4
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Tagay Y, Kheirabadi S, Ataie Z, Singh RK, Prince O, Nguyen A, Zhovmer AS, Ma X, Sheikhi A, Tsygankov D, Tabdanov ED. Dynein-Powered Cell Locomotion Guides Metastasis of Breast Cancer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2302229. [PMID: 37726225 PMCID: PMC10625109 DOI: 10.1002/advs.202302229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 08/20/2023] [Indexed: 09/21/2023]
Abstract
The principal cause of death in cancer patients is metastasis, which remains an unresolved problem. Conventionally, metastatic dissemination is linked to actomyosin-driven cell locomotion. However, the locomotion of cancer cells often does not strictly line up with the measured actomyosin forces. Here, a complementary mechanism of metastatic locomotion powered by dynein-generated forces is identified. These forces arise within a non-stretchable microtubule network and drive persistent contact guidance of migrating cancer cells along the biomimetic collagen fibers. It is also shown that the dynein-powered locomotion becomes indispensable during invasive 3D migration within a tissue-like luminal network formed by spatially confining granular hydrogel scaffolds (GHS) made up of microscale hydrogel particles (microgels). These results indicate that the complementary motricity mediated by dynein is always necessary and, in certain instances, sufficient for disseminating metastatic breast cancer cells. These findings advance the fundamental understanding of cell locomotion mechanisms and expand the spectrum of clinical targets against metastasis.
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Affiliation(s)
- Yerbol Tagay
- Department of PharmacologyPenn State College of MedicineThe Pennsylvania State UniversityHersheyPA17033USA
| | - Sina Kheirabadi
- Department of Chemical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Zaman Ataie
- Department of Chemical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Rakesh K. Singh
- Department of Obstetrics & GynecologyGynecology OncologyUniversity of Rochester Medical CenterRochesterNY14642USA
| | - Olivia Prince
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMD20903USA
| | - Ashley Nguyen
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMD20903USA
| | - Alexander S. Zhovmer
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMD20903USA
| | - Xuefei Ma
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMD20903USA
| | - Amir Sheikhi
- Department of Chemical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Denis Tsygankov
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA30332USA
| | - Erdem D. Tabdanov
- Department of PharmacologyPenn State College of MedicineThe Pennsylvania State UniversityHersheyPA17033USA
- Penn State Cancer InstitutePenn State College of MedicineThe Pennsylvania State UniversityHersheyPA17033USA
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5
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Ma TC, Gicking AM, Feng Q, Hancock WO. Simulations suggest robust microtubule attachment of kinesin and dynein in antagonistic pairs. Biophys J 2023; 122:3299-3313. [PMID: 37464742 PMCID: PMC10465704 DOI: 10.1016/j.bpj.2023.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 05/04/2023] [Accepted: 07/10/2023] [Indexed: 07/20/2023] Open
Abstract
Intracellular transport is propelled by kinesin and cytoplasmic dynein motors that carry membrane-bound vesicles and organelles bidirectionally along microtubule tracks. Much is known about these motors at the molecular scale, but many questions remain regarding how kinesin and dynein cooperate and compete during bidirectional cargo transport at the cellular level. The goal of the present study was to use a stochastic stepping model constructed by using published load-dependent properties of kinesin-1 and dynein-dynactin-BicD2 (DDB) to identify specific motor properties that determine the speed, directionality, and transport dynamics of a cargo carried by one kinesin and one dynein motor. Model performance was evaluated by comparing simulations to recently published experiments of kinesin-DDB pairs connected by complementary oligonucleotide linkers. Plotting the instantaneous velocity distributions from kinesin-DDB experiments revealed a single peak centered around zero velocity. In contrast, velocity distributions from simulations displayed a central peak around 100 nm/s, along with two side peaks corresponding to the unloaded kinesin and DDB velocities. We hypothesized that frequent motor detachment events and relatively slow motor reattachment rates resulted in periods in which only one motor is attached. To investigate this hypothesis, we varied specific model parameters and compared the resulting instantaneous velocity distributions, and we confirmed this systematic investigation using a machine-learning approach that minimized the residual sum of squares between the experimental and simulation velocity distributions. The experimental data were best recapitulated by a model in which the kinesin and dynein stall forces are matched, the motor detachment rates are independent of load, and the kinesin-1 reattachment rate is 50 s-1. These results provide new insights into motor dynamics during bidirectional transport and put forth hypotheses that can be tested by future experiments.
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Affiliation(s)
- Tzu-Chen Ma
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Allison M Gicking
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Qingzhou Feng
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - William O Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania; Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania.
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6
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Monteiro P, Yeon B, Wallis SS, Godinho SA. Centrosome amplification fine tunes tubulin acetylation to differentially control intracellular organization. EMBO J 2023; 42:e112812. [PMID: 37403793 PMCID: PMC10425843 DOI: 10.15252/embj.2022112812] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 06/05/2023] [Accepted: 06/14/2023] [Indexed: 07/06/2023] Open
Abstract
Intracellular organelle organization is conserved in eukaryotic cells and is primarily achieved through active transport by motor proteins along the microtubule cytoskeleton. Microtubule post-translational modifications (PTMs) can contribute to microtubule diversity and differentially regulate motor-mediated transport. Here, we show that centrosome amplification, commonly observed in cancer and shown to promote aneuploidy and invasion, induces a global change in organelle positioning towards the cell periphery and facilitates nuclear migration through confined spaces. This reorganization requires kinesin-1 and is analogous to the loss of dynein. Cells with amplified centrosomes display increased levels of acetylated tubulin, a PTM that could enhance kinesin-1-mediated transport. Depletion of α-tubulin acetyltransferase 1 (αTAT1) to block tubulin acetylation rescues the displacement of centrosomes, mitochondria, and vimentin but not Golgi or endosomes. Analyses of the distribution of total and acetylated microtubules indicate that the polarized distribution of modified microtubules, rather than levels alone, plays an important role in the positioning of specific organelles, such as the centrosome. We propose that increased tubulin acetylation differentially impacts kinesin-1-mediated organelle displacement to regulate intracellular organization.
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Affiliation(s)
- Pedro Monteiro
- Centre for Cancer Cell and Molecular Biology, Barts Cancer InstituteQueen Mary University of LondonLondonUK
- Institut Curie, Paris Sciences and Lettres Research UniversityCentre National de la Recherche Scientifique, UMR144ParisFrance
| | - Bongwhan Yeon
- Centre for Cancer Cell and Molecular Biology, Barts Cancer InstituteQueen Mary University of LondonLondonUK
| | - Samuel S Wallis
- Centre for Cancer Cell and Molecular Biology, Barts Cancer InstituteQueen Mary University of LondonLondonUK
| | - Susana A Godinho
- Centre for Cancer Cell and Molecular Biology, Barts Cancer InstituteQueen Mary University of LondonLondonUK
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7
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Tagay Y, Kheirabadi S, Ataie Z, Singh RK, Prince O, Nguyen A, Zhovmer AS, Ma X, Sheikhi A, Tsygankov D, Tabdanov ED. Dynein-Powered Cell Locomotion Guides Metastasis of Breast Cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.04.535605. [PMID: 37066378 PMCID: PMC10104034 DOI: 10.1101/2023.04.04.535605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Metastasis is a principal cause of death in cancer patients, which remains an unresolved fundamental and clinical problem. Conventionally, metastatic dissemination is linked to the actomyosin-driven cell locomotion. However, locomotion of cancer cells often does not strictly line up with the measured actomyosin forces. Here, we identify a complementary mechanism of metastatic locomotion powered by the dynein-generated forces. These forces that arise within a non-stretchable microtubule network drive persistent contact guidance of migrating cancer cells along the biomimetic collagen fibers. We also show that dynein-powered locomotion becomes indispensable during invasive 3D migration within a tissue-like luminal network between spatially confining hydrogel microspheres. Our results indicate that the complementary contractile system of dynein motors and microtubules is always necessary and in certain instances completely sufficient for dissemination of metastatic breast cancer cells. These findings advance fundamental understanding of cell locomotion mechanisms and expand the spectrum of clinical targets against metastasis.
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Affiliation(s)
- Yerbol Tagay
- Department of Pharmacology, Penn State College of Medicine, The Pennsylvania State University, Hershey, PA, 17033, USA
| | - Sina Kheirabadi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zaman Ataie
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Rakesh K. Singh
- Department of Obstetrics & Gynecology, University of Rochester Medical Center, Rochester, NY, USA
| | - Olivia Prince
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20903, USA
| | - Ashley Nguyen
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20903, USA
| | - Alexander S. Zhovmer
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20903, USA
| | - Xuefei Ma
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20903, USA
| | - Amir Sheikhi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Denis Tsygankov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
| | - Erdem D. Tabdanov
- Department of Pharmacology, Penn State College of Medicine, The Pennsylvania State University, Hershey, PA, 17033, USA
- Penn State Cancer Institute, Penn State College of Medicine, The Pennsylvania State University, Hershey, PA, 17033, USA
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8
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Munoz O, Klumpp S. Tug-of-War and Coordination in Bidirectional Transport by Molecular Motors. J Phys Chem B 2022; 126:7957-7965. [PMID: 36194780 DOI: 10.1021/acs.jpcb.2c05194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many cargoes in cells are transported in a bidirectional fashion by molecular motors pulling into opposite directions along a cytoskeletal filament, e.g., by kinesins and dyneins along microtubules. How opposite-polarity motors are coordinated has been under debate for a long time, with experimental evidence supporting both a tug-of-war between the motors as well as biochemical coordination mechanisms. Here we propose a model that extends a tug-of-war model by a mechanism of motor activation and inactivation and show that this model can explain some observations that are incompatible with a simple tug-of-war scenario, specifically long unidirectional runs and a directional memory after unbinding from the filament. Both features are present in two variants of the model in which motors are activated and inactivated individually and in opposite-direction pairs, respectively.
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Affiliation(s)
- Omar Munoz
- Institute for the Dynamics of Complex Systems, University of Göttingen, Friedrich-Hund-Platz 1, 37077Göttingen, Germany
| | - Stefan Klumpp
- Institute for the Dynamics of Complex Systems, University of Göttingen, Friedrich-Hund-Platz 1, 37077Göttingen, Germany
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9
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Using Fluorescence Recovery After Photobleaching data to uncover filament dynamics. PLoS Comput Biol 2022; 18:e1010573. [PMID: 36156590 PMCID: PMC9536589 DOI: 10.1371/journal.pcbi.1010573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 10/06/2022] [Accepted: 09/14/2022] [Indexed: 11/20/2022] Open
Abstract
Fluorescence Recovery After Photobleaching (FRAP) has been extensively used to understand molecular dynamics in cells. This technique when applied to soluble, globular molecules driven by diffusion is easily interpreted and well understood. However, the classical methods of analysis cannot be applied to anisotropic structures subjected to directed transport, such as cytoskeletal filaments or elongated organelles transported along microtubule tracks. A new mathematical approach is needed to analyze FRAP data in this context and determine what information can be obtain from such experiments. To address these questions, we analyze fluorescence intensity profile curves after photobleaching of fluorescently labelled intermediate filaments anterogradely transported along microtubules. We apply the analysis to intermediate filament data to determine information about the filament motion. Our analysis consists of deriving equations for fluorescence intensity profiles and developing a mathematical model for the motion of filaments and simulating the model. Two closed forms for profile curves were derived, one for filaments of constant length and one for filaments with constant velocity, and three types of simulation were carried out. In the first type of simulation, the filaments have random velocities which are constant for the duration of the simulation. In the second type, filaments have random velocities which instantaneously change at random times. In the third type, filaments have random velocities and exhibit pausing between velocity changes. Our analysis shows: the most important distribution governing the shape of the intensity profile curves obtained from filaments is the distribution of the filament velocity. Furthermore, filament length which is constant during the experiment, had little impact on intensity profile curves. Finally, gamma distributions for the filament velocity with pauses give the best fit to asymmetric fluorescence intensity profiles of intermediate filaments observed in FRAP experiments performed in polarized migrating astrocytes. Our analysis also shows that the majority of filaments are stationary. Overall, our data give new insight into the regulation of intermediate filament dynamics during cell migration. Fluorescence Recovery After Photobleaching (FRAP) is a commonly-used technique to analyze the dynamics of fluorescently-tagged proteins or structures in biology. After photochemical altering the fluorophor in a specific region, fluorescent material from the surrounding region moves into the photobleached region. Usually applied to the diffusion of soluble or membrane associate proteins, the existing models of analysis are not suitable for the elucidation of directional transport of elongated structures. Different modes of motions for the elongated structures with distributed lengths and velocities in cells are considered. First, we observe that filament lengths can be inferred from the level of noisiness. We further show the characteristics of fluorescence profile curves mainly depend on the occurrence of changes in velocities and distributions of velocities; whereas length distributions have negligible impact. Analysis of experimental data using this new framework indicates intermediate filaments transported by kinesins along microtubules in polarized migrating cells have gamma distributed velocities changing over time between pausing. Most filaments are found to be very slow or stationary with a few moving fast. This new computational approach should permit the interpretation of FRAP experimental data obtained with any directionally moving elongated structures of various lengths.
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10
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Selective motor activation in organelle transport along axons. Nat Rev Mol Cell Biol 2022; 23:699-714. [DOI: 10.1038/s41580-022-00491-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2022] [Indexed: 12/17/2022]
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11
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Hilverling A, Szegö EM, Dinter E, Cozma D, Saridaki T, Falkenburger BH. Maturing Autophagosomes are Transported Towards the Cell Periphery. Cell Mol Neurobiol 2021; 42:155-171. [PMID: 34106361 PMCID: PMC8732932 DOI: 10.1007/s10571-021-01116-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 06/04/2021] [Indexed: 12/12/2022]
Abstract
Autophagosome maturation comprises fusion with lysosomes and acidification. It is a critical step in the degradation of cytosolic protein aggregates that characterize many neurodegenerative diseases. In order to better understand this process, we studied intracellular trafficking of autophagosomes and aggregates of α-synuclein, which characterize Parkinson's disease and other synucleinopathies. The autophagosomal marker LC3 and the aggregation prone A53T mutant of α-synuclein were tagged by fluorescent proteins and expressed in HEK293T cells and primary astrocytes. The subcellular distribution and movement of these vesicle populations were analyzed by (time-lapse) microscopy. Fusion with lysosomes was assayed using the lysosomal marker LAMP1; vesicles with neutral and acidic luminal pH were discriminated using the RFP-GFP "tandem-fluorescence" tag. With respect to vesicle pH, we observed that neutral autophagosomes, marked by LC3 or synuclein, were located more frequently in the cell center, and acidic autophagosomes were observed more frequently in the cell periphery. Acidic autophagosomes were transported towards the cell periphery more often, indicating that acidification occurs in the cell center before transport to the periphery. With respect to autolysosomal fusion, we found that lysosomes preferentially moved towards the cell center, whereas autolysosomes moved towards the cell periphery, suggesting a cycle where lysosomes are generated in the periphery and fuse to autophagosomes in the cell center. Unexpectedly, many acidic autophagosomes were negative for LAMP1, indicating that acidification does not require fusion to lysosomes. Moreover, we found both neutral and acidic vesicles positive for LAMP1, consistent with delayed acidification of the autolysosome lumen. Individual steps of aggregate clearance thus occur in dedicated cellular regions. During aggregate clearance, autophagosomes and autolysosomes form in the center and are transported towards the periphery during maturation. In this process, luminal pH could regulate the direction of vesicle transport. (1) Transport and location of autophagosomes depend on luminal pH: Acidic autophagosomes are preferentially transported to the cell periphery, causing more acidic autophagosomes in the cell periphery and more neutral autophagosomes at the microtubule organizing center (MTOC). (2) Autolysosomes are transported to the cell periphery and lysosomes to the MTOC, suggesting spatial segregation of lysosome reformation and autolysosome fusion. (3) Synuclein aggregates are preferentially located at the MTOC and synuclein-containing vesicles in the cell periphery, consistent with transport of aggregates to the MTOC for autophagy.
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Affiliation(s)
- Anna Hilverling
- Department of Neurology, RWTH Aachen University, Aachen, Germany
| | - Eva M Szegö
- Department of Neurology, Technische Universität Dresden, Dresden, Germany
| | - Elisabeth Dinter
- Department of Neurology, Technische Universität Dresden, Dresden, Germany
| | - Diana Cozma
- Department of Neurology, Technische Universität Dresden, Dresden, Germany
| | | | - Björn H Falkenburger
- Department of Neurology, RWTH Aachen University, Aachen, Germany.
- Department of Neurology, Technische Universität Dresden, Dresden, Germany.
- JARA-Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany.
- Deutsches Zentrum Für Neurodegenerative Erkrankungen, Dresden, Germany.
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