1
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Omer S, Li J, Yang CX, Harrison RE. Ninein promotes F-actin cup formation and inward phagosome movement during phagocytosis in macrophages. Mol Biol Cell 2024; 35:ar26. [PMID: 38117588 PMCID: PMC10916867 DOI: 10.1091/mbc.e23-06-0216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 11/30/2023] [Accepted: 12/12/2023] [Indexed: 12/22/2023] Open
Abstract
Phagocytosis by macrophages is a highly polarized process to destroy large target cells. Binding to particles induces extensive cortical actin-generated forces that drive the formation of elaborate pseudopods around the target particle. Postinternalization, the resultant phagosome is driven toward the cell interior on microtubules (MTs) by cytoplasmic dynein. However, it is unclear whether dynein and cargo-adaptors contribute to the earlier steps of particle internalization and phagosome formation. Here we reveal that ninein, a MT minus-end-associated protein that localizes to the centrosome, is also present at the phagocytic cup in macrophages. Ninein depletion impairs particle internalization by delaying the early F-actin recruitment to sites of particle engagement and cup formation, with no impact on F-actin dynamics beyond this initial step. Ninein forms membrane-bound clusters on phagocytic cups that do not nucleate acentrosomal MTs but instead mediate the assembly of dynein-dynactin complex at active phagocytic membranes. Both ninein depletion and pharmacological inhibition of dynein activity reduced inward displacement of bound particles into macrophages. We found that ninein and dynein motor activity were required for timely retrograde movement of phagosomes and for phagolysosome formation. Taken together, these data show that ninein, alone and with dynein, play significant roles during phagocytosis.
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Affiliation(s)
- Safia Omer
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4
| | - Jiahao Li
- Department of Cell & Systems Biology, University of Toronto Scarborough, Toronto, Ontario M1C 1A4
| | - Claire X. Yang
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4
| | - Rene E. Harrison
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4
- Department of Cell & Systems Biology, University of Toronto Scarborough, Toronto, Ontario M1C 1A4
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2
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Adrian M, Weber M, Tsai MC, Glock C, Kahn OI, Phu L, Cheung TK, Meilandt WJ, Rose CM, Hoogenraad CC. Polarized microtubule remodeling transforms the morphology of reactive microglia and drives cytokine release. Nat Commun 2023; 14:6322. [PMID: 37813836 PMCID: PMC10562429 DOI: 10.1038/s41467-023-41891-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 09/19/2023] [Indexed: 10/11/2023] Open
Abstract
Microglial reactivity is a pathological hallmark in many neurodegenerative diseases. During stimulation, microglia undergo complex morphological changes, including loss of their characteristic ramified morphology, which is routinely used to detect and quantify inflammation in the brain. However, the underlying molecular mechanisms and the relation between microglial morphology and their pathophysiological function are unknown. Here, proteomic profiling of lipopolysaccharide (LPS)-reactive microglia identifies microtubule remodeling pathways as an early factor that drives the morphological change and subsequently controls cytokine responses. We find that LPS-reactive microglia reorganize their microtubules to form a stable and centrosomally-anchored array to facilitate efficient cytokine trafficking and release. We identify cyclin-dependent kinase 1 (Cdk-1) as a critical upstream regulator of microtubule remodeling and morphological change in-vitro and in-situ. Cdk-1 inhibition also rescues tau and amyloid fibril-induced morphology changes. These results demonstrate a critical role for microtubule dynamics and reorganization in microglial reactivity and modulating cytokine-mediated inflammatory responses.
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Affiliation(s)
- Max Adrian
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA, 94080, USA
- Department of Pathology, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Martin Weber
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Ming-Chi Tsai
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Caspar Glock
- Department of OMNI Bioinformatics, Genentech Inc., South San Francisco, CA, 94080, USA
| | - Olga I Kahn
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Lilian Phu
- Department of Microchemistry, Proteomics and Lipidomics, South San Francisco, CA, 94080, USA
| | - Tommy K Cheung
- Department of Microchemistry, Proteomics and Lipidomics, South San Francisco, CA, 94080, USA
| | - William J Meilandt
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Christopher M Rose
- Department of Microchemistry, Proteomics and Lipidomics, South San Francisco, CA, 94080, USA
| | - Casper C Hoogenraad
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA, 94080, USA.
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3
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Lyu Y, Ren Y, Qu K, Quji S, Zhuzha B, Lei C, Chen N. Local ancestry and selection in admixed Sanjiang cattle. STRESS BIOLOGY 2023; 3:30. [PMID: 37676416 PMCID: PMC10441984 DOI: 10.1007/s44154-023-00101-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 06/29/2023] [Indexed: 09/08/2023]
Abstract
The majority of native cattle are taurine × indicine cattle of diverse phenotypes in the central region of China. Sanjiang cattle, a typical breed in the central region, play a central role in human livelihood and have good adaptability, including resistance to dampness, heat, roughage, and disease, and are thus regarded as an important genetic resource. However, the genetic history of the successful breed remains unknown. Here, we sequenced 10 Sanjiang cattle genomes and compared them to the 70 genomes of 5 representative populations worldwide. We characterized the genomic diversity and breed formation process of Sanjiang cattle and found that Sanjiang cattle have a mixed ancestry of indicine (55.6%) and taurine (33.2%) dating to approximately 30 generations ago, which has shaped the genome of Sanjiang cattle. Through ancestral fragment inference, selective sweep and transcriptomic analysis, we identified several genes linked to lipid metabolism, immune regulation, and stress reactions across the mosaic genome of Sanjiang cattle showing an excess of taurine or indicine ancestry. Taurine ancestry might contribute to meat quality, and indicine ancestry is more conducive to adaptation to hot climate conditions, making Sanjiang cattle a valuable genetic resource for the central region of China. Our results will help us understand the evolutionary history and ancestry components of Sanjiang cattle, which will provide a reference for resource conservation and selective breeding of Chinese native cattle.
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Affiliation(s)
- Yang Lyu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Yaxuan Ren
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Kaixing Qu
- Academy of Science and Technology, Chuxiong Normal University, Chuxiong, China
| | - Suolang Quji
- Institute of Animal Husbandry and Veterinary Science, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, China
| | - Basang Zhuzha
- Institute of Animal Husbandry and Veterinary Science, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, China
| | - Chuzhao Lei
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China.
| | - Ningbo Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China.
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4
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Shukla S, Troitskaia A, Swarna N, Maity BK, Tjioe M, Bookwalter CS, Trybus KM, Chemla YR, Selvin PR. High-throughput force measurement of individual kinesin-1 motors during multi-motor transport. NANOSCALE 2022; 14:12463-12475. [PMID: 35980233 PMCID: PMC9983033 DOI: 10.1039/d2nr01701f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molecular motors often work in teams to move a cellular cargo. Yet measuring the forces exerted by each motor is challenging. Using a sensor made with denatured ssDNA and multi-color fluorescence, we measured picoNewtons of forces and nanometer distances exerted by individual constrained kinesin-1 motors acting together while driving a common microtubule in vitro. We find that kinesins primarily exerted less than 1 pN force, even while the microtubule is bypassing artificial obstacles of 20-100 nanometer size. Occasionally, individual forces increase upon encountering obstacles, although at other times they do not, with the cargo continuing in a directional manner. Our high-throughput technique, which can measure forces by many motors simultaneously, is expected to be useful for many different types of molecular motors.
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Affiliation(s)
- Saurabh Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
| | - Alice Troitskaia
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Nikhila Swarna
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Barun Kumar Maity
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Marco Tjioe
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Carol S Bookwalter
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Kathleen M Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Yann R Chemla
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Paul R Selvin
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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5
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Fokin AI, Gautreau AM. Assembly and Activity of the WASH Molecular Machine: Distinctive Features at the Crossroads of the Actin and Microtubule Cytoskeletons. Front Cell Dev Biol 2021; 9:658865. [PMID: 33869225 PMCID: PMC8047104 DOI: 10.3389/fcell.2021.658865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/12/2021] [Indexed: 01/10/2023] Open
Abstract
The Arp2/3 complex generates branched actin networks at different locations of the cell. The WASH and WAVE Nucleation Promoting Factors (NPFs) activate the Arp2/3 complex at the surface of endosomes or at the cell cortex, respectively. In this review, we will discuss how these two NPFs are controlled within distinct, yet related, multiprotein complexes. These complexes are not spontaneously assembled around WASH and WAVE, but require cellular assembly factors. The centrosome, which nucleates microtubules and branched actin, appears to be a privileged site for WASH complex assembly. The actin and microtubule cytoskeletons are both responsible for endosome shape and membrane remodeling. Motors, such as dynein, pull endosomes and extend membrane tubules along microtubule tracks, whereas branched actin pushes onto the endosomal membrane. It was recently uncovered that WASH assembles a super complex with dynactin, the major dynein activator, where the Capping Protein (CP) is exchanged from dynactin to the WASH complex. This CP swap initiates the first actin filament that primes the autocatalytic nucleation of branched actin at the surface of endosomes. Possible coordination between pushing and pulling forces in the remodeling of endosomal membranes is discussed.
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Affiliation(s)
- Artem I. Fokin
- Laboratoire de Biologie Structurale de la Cellule, CNRS, Ecole Polytechnique, IP Paris, Palaiseau, France
| | - Alexis M. Gautreau
- Laboratoire de Biologie Structurale de la Cellule, CNRS, Ecole Polytechnique, IP Paris, Palaiseau, France
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
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6
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He L, Weng H, Li Q, Shi G, Liu X, Du Y, Zheng J, Ling W, Wang D. Lactucopicrin Inhibits Cytoplasmic Dynein-Mediated NF-κB Activation in Inflammated Macrophages and Alleviates Atherogenesis in Apolipoprotein E-Deficient Mice. Mol Nutr Food Res 2021; 65:e2000989. [PMID: 33377310 DOI: 10.1002/mnfr.202000989] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/03/2020] [Indexed: 12/15/2022]
Abstract
SCOPE Nuclear factor-κB (NF-κB) activation in macrophages aggravates atherosclerosis. Dietary plant secondary metabolites including sesquiterpene lactone lactucopicrin target multiple organs. This study is focused on the impact of lactucopicrin on NF-κB activation in inflammed macrophages and atherogenesis in a mouse model of atherosclerosis. METHODS AND RESULTS In LPS-stimulated mouse bone marrow-derived macrophages, lactucopicrin inhibits NF-κB activation, and concomitantly represses the expression of IL-1β, IL-6, and tumor necrosis factor-alpha. This effect is not due to modulation of the inhibitor of NF-κB kinases (IKK) α/β/γ and NF-κB inhibitor α, and NF-κB/p65 DNA binding activity. Instead, the lactucopicrin effect is reliant on the inhibition of cytoplasmic dynein-mediated p65 transportation, a prerequisite step for p65 nuclear translocation. In high-fat diet-fed apolipoprotein E-deficient mice, lactucopicrin consumption dose-dependently reduces plaque area, inhibits plaque macrophage accumulation, attenuates plaque macrophage NF-κB activation, and reduces both plaque and serum inflammatory burden. However, lactucopicrin consumption does not affect the levels of serum lipids and anti-inflammatory cytokines (IL-4, IL-10, and transforming growth factor beta). CONCLUSION Dietary lactucopicrin inhibits atherogenesis in mice likely by its anti-inflammatory property. These findings suggest that dietary supplementation with lactucopicrin is a promising strategy to inhibit atherosclerotic cardiovascular disease.
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Affiliation(s)
- Luanying He
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
| | - Hui Weng
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
| | - Qing Li
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
| | - Guojun Shi
- Department of Endocrinology & Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Xiuping Liu
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
| | - Yushi Du
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
| | - Jiakun Zheng
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
| | - Wenhua Ling
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
- Guangdong Provincial Key Laboratory for Food, Nutrition and Health, Guangzhou, P. R. China
- Guangdong Engineering Technology Research Center for Nutrition Translation, Guangzhou, P. R. China
| | - Dongliang Wang
- Department of Nutrition, School of Public Health, Sun Yat-sen University (Northern Campus), Guangzhou, P. R. China
- Guangdong Provincial Key Laboratory for Food, Nutrition and Health, Guangzhou, P. R. China
- Guangdong Engineering Technology Research Center for Nutrition Translation, Guangzhou, P. R. China
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7
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Gambino G, Rizzo V, Giglia G, Ferraro G, Sardo P. Microtubule Dynamics and Neuronal Excitability: Advances on Cytoskeletal Components Implicated in Epileptic Phenomena. Cell Mol Neurobiol 2020; 42:533-543. [PMID: 32929563 PMCID: PMC8891195 DOI: 10.1007/s10571-020-00963-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/05/2020] [Indexed: 12/14/2022]
Abstract
Extensive researches have deepened knowledge on the role of synaptic components in epileptogenesis, but limited attention has been devoted to the potential implication of the cytoskeleton. The study of the development of epilepsy and hyperexcitability states involves molecular, synaptic, and structural alterations of neuronal bioelectric activity. In this paper we aim to explore the neurobiological targets involved in microtubule functioning and cytoskeletal transport, i.e. how dynamic scaffolding of microtubules can influence neuronal morphology and excitability, in order to suggest a potential role for microtubule dynamics in the processes turning a normal neuronal network in a hyperexcited one. Pathophysiological alterations of microtubule dynamics inducing neurodegeneration, network remodeling and relative impairment on synaptic transmission were overviewed. Recent researches were reported on the phosphorylation state of microtubule-associated proteins such as tau in neurodegenerative diseases and epileptic states, but also on the effect of microtubule-active agents influencing cytoskeleton destabilization in epilepsy models. The manipulation of microtubule polymerization was found effective in the modulation of hyperexcitability. In addition, it was considered the importance of microtubules and related neurotrophic factors during neural development since they are essential for the formation of a properly functional neuronal network. Otherwise, this can lead to cognitive deficits, hyperexcitability phenomena and neurodevelopmental disorders. Lastly, we evaluated the role of microtubule dynamics on neuronal efficiency considering their importance in the transport of mitochondria, cellular elements fulfilling energy requirements for neuronal activity, and a putative influence on cannabinoid-mediated neuroprotection. This review provides novel perspectives for the implication of microtubule dynamics in the development of epileptic phenomena.
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Affiliation(s)
- Giuditta Gambino
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione Di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
| | - Valerio Rizzo
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione Di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
| | - Giuseppe Giglia
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione Di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy.
| | - Giuseppe Ferraro
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione Di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
| | - Pierangelo Sardo
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione Di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
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8
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Salavati M, Bush SJ, Palma-Vera S, McCulloch MEB, Hume DA, Clark EL. Elimination of Reference Mapping Bias Reveals Robust Immune Related Allele-Specific Expression in Crossbred Sheep. Front Genet 2019; 10:863. [PMID: 31608110 PMCID: PMC6761296 DOI: 10.3389/fgene.2019.00863] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/19/2019] [Indexed: 12/13/2022] Open
Abstract
Pervasive allelic variation at both gene and single nucleotide level (SNV) between individuals is commonly associated with complex traits in humans and animals. Allele-specific expression (ASE) analysis, using RNA-Seq, can provide a detailed annotation of allelic imbalance and infer the existence of cis-acting transcriptional regulation. However, variant detection in RNA-Seq data is compromised by biased mapping of reads to the reference DNA sequence. In this manuscript, we describe an unbiased standardized computational pipeline for allele-specific expression analysis using RNA-Seq data, which we have adapted and developed using tools available under open license. The analysis pipeline we present is designed to minimize reference bias while providing accurate profiling of allele-specific expression across tissues and cell types. Using this methodology, we were able to profile pervasive allelic imbalance across tissues and cell types, at both the gene and SNV level, in Texel×Scottish Blackface sheep, using the sheep gene expression atlas data set. ASE profiles were pervasive in each sheep and across all tissue types investigated. However, ASE profiles shared across tissues were limited, and instead, they tended to be highly tissue-specific. These tissue-specific ASE profiles may underlie the expression of economically important traits and could be utilized as weighted SNVs, for example, to improve the accuracy of genomic selection in breeding programs for sheep. An additional benefit of the pipeline is that it does not require parental genotypes and can therefore be applied to other RNA-Seq data sets for livestock, including those available on the Functional Annotation of Animal Genomes (FAANG) data portal. This study is the first global characterization of moderate to extreme ASE in tissues and cell types from sheep. We have applied a robust methodology for ASE profiling to provide both a novel analysis of the multi-dimensional sheep gene expression atlas data set and a foundation for identifying the regulatory and expressed elements of the genome that are driving complex traits in livestock.
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Affiliation(s)
- Mazdak Salavati
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Stephen J. Bush
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Sergio Palma-Vera
- Leibniz Institute for Farm Animal Biology (FBN), Institute for Reproductive Biology, Dummerstorf, Germany
| | - Mary E. B. McCulloch
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - David A. Hume
- Mater Research Institute-University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
| | - Emily L. Clark
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
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9
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Luo S, Jing L, Zhao T, Li Y, Liu Z, Diao A. Ubiquitination and dynactin regulate TMEPAI lysosomal trafficking. Sci Rep 2017; 7:42668. [PMID: 28218281 PMCID: PMC5316989 DOI: 10.1038/srep42668] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/13/2017] [Indexed: 12/17/2022] Open
Abstract
The transmembrane prostate androgen-induced protein (TMEPAI) has been reported to be elevated in various tumor cells, is localized to the lysosome and promotes lysosome stability. The molecular mechanism of TMEPAI trafficking however to the lysosome is unknown. Here we report that clathrin and CI-M6PR mediate TMEPAI transport from the Golgi directly into the endo-lysosomal pathway. TMEPAI is ubiquitinated at its C-terminal region and ubiquitination modification of TMEPAI is a signal for its lysosomal trafficking. Moreover, TMEPAI binds the ubiquitin binding proteins Hrs and STAM which is required for its lysosomal transport. In addition, TMEPAI interacts with the dynactin pointed-end complex subunits dynactin 5 and dynactin 6. The aa 132–155 domain is essential for specific TMEPAI binding and deletion of this binding site leads to mis-trafficking of TMEPAI to the plasma membrane. These results reveal the pathway and mechanism regulating transport of TMEPAI to the lysosome, which helps to further understand the role of TMEPAI in tumorigenesis.
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Affiliation(s)
- Shenheng Luo
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin, 300457, China
| | - Lei Jing
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin, 300457, China
| | - Tian Zhao
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin, 300457, China
| | - Yuyin Li
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin, 300457, China
| | - Zhenxing Liu
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin, 300457, China
| | - Aipo Diao
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin, 300457, China
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10
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Tarrant DJ, Stirpe M, Rowe M, Howard MJ, von der Haar T, Gourlay CW. Inappropriate expression of the translation elongation factor 1A disrupts genome stability and metabolism. J Cell Sci 2016; 129:4455-4465. [PMID: 27807005 PMCID: PMC5201016 DOI: 10.1242/jcs.192831] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 10/26/2016] [Indexed: 02/02/2023] Open
Abstract
The translation elongation factor eEF1A is one of the most abundant proteins found within cells, and its role within protein synthesis is well documented. Levels of eEF1A are tightly controlled, with inappropriate expression linked to oncogenesis. However, the mechanisms by which increased eEF1A expression alters cell behaviour are unknown. Our analyses in yeast suggest that elevation of eEF1A levels leads to stabilisation of the spindle pole body and changes in nuclear organisation. Elevation of the eEF1A2 isoform also leads to altered nuclear morphology in cultured human cells, suggesting a conserved role in maintaining genome stability. Gene expression and metabolomic analyses reveal that the level of eEF1A is crucial for the maintenance of metabolism and amino acid levels in yeast, most likely because of its role in the control of vacuole function. Increased eEF1A2 levels trigger lysosome biogenesis in cultured human cells, also suggesting a conserved role within metabolic control mechanisms. Taken together, our data suggest that the control of eEF1A levels is important for the maintenance of a number of cell functions beyond translation and that its de-regulation might contribute to its oncogenic properties. Summary: The translation elongation factor eEF1A is elevated in some cancers. We use yeast and human cell models to show that eEF1A elevation leads to genome instability and metabolic alterations that might affect its oncogenic properties.
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Affiliation(s)
- Daniel J Tarrant
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Mariarita Stirpe
- Department of Biology and Biotechnology, Sapienza, University of Rome, 00185 Rome, Italy
| | - Michelle Rowe
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Mark J Howard
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Tobias von der Haar
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Campbell W Gourlay
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
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11
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Rai A, Pathak D, Thakur S, Singh S, Dubey AK, Mallik R. Dynein Clusters into Lipid Microdomains on Phagosomes to Drive Rapid Transport toward Lysosomes. Cell 2016; 164:722-34. [PMID: 26853472 PMCID: PMC4752818 DOI: 10.1016/j.cell.2015.12.054] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/26/2015] [Accepted: 12/23/2015] [Indexed: 01/19/2023]
Abstract
Diverse cellular processes are driven by motor proteins that are recruited to and generate force on lipid membranes. Surprisingly little is known about how membranes control the force from motors and how this may impact specific cellular functions. Here, we show that dynein motors physically cluster into microdomains on the membrane of a phagosome as it matures inside cells. Such geometrical reorganization allows many dyneins within a cluster to generate cooperative force on a single microtubule. This results in rapid directed transport of the phagosome toward microtubule minus ends, likely promoting phagolysosome fusion and pathogen degradation. We show that lipophosphoglycan, the major molecule implicated in immune evasion of Leishmania donovani, inhibits phagosome motion by disrupting the clustering and therefore the cooperative force generation of dynein. These findings appear relevant to several pathogens that prevent phagosome-lysosome fusion by targeting lipid microdomains on phagosomes. Dynein clusters into lipid microdomains on the phagosome as it matures Clustering allows many dyneins to simultaneously contact a single microtubule Large cooperative forces can now be generated to transport phagosomes to lysosomes Leishmania lipophosphoglycans disrupt microdomains and inhibit this transport
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Affiliation(s)
- Ashim Rai
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Divya Pathak
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Shreyasi Thakur
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Shampa Singh
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Alok Kumar Dubey
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Roop Mallik
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
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Hoogenraad CC, Akhmanova A. Bicaudal D Family of Motor Adaptors: Linking Dynein Motility to Cargo Binding. Trends Cell Biol 2016; 26:327-340. [PMID: 26822037 DOI: 10.1016/j.tcb.2016.01.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 01/03/2016] [Accepted: 01/04/2016] [Indexed: 01/24/2023]
Abstract
Transport of different intracellular cargoes along cytoskeleton filaments is essential for the morphogenesis and function of a broad variety of eukaryotic cells. Intracellular transport is mediated by cytoskeletal motors including myosin, kinesin, and dynein, which are typically linked to various cargoes by adaptor proteins. Recent studies suggest that adaptor proteins can also act as essential transport cofactors, which control motor activity and coordination. Characterization of the evolutionary conserved Bicaudal D (BICD) family of dynein adaptor proteins has provided important insights into the fundamental mechanisms governing cargo trafficking. This review highlights the advances in the current understanding of how BICD adaptors regulate microtubule-based transport and how they contribute to developmental processes and human disease.
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Affiliation(s)
- Casper C Hoogenraad
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht, CH 3584 The Netherlands.
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht, CH 3584 The Netherlands.
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Schlager MA, Hoang HT, Urnavicius L, Bullock SL, Carter AP. In vitro reconstitution of a highly processive recombinant human dynein complex. EMBO J 2014; 33:1855-68. [PMID: 24986880 PMCID: PMC4158905 DOI: 10.15252/embj.201488792] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Cytoplasmic dynein is an approximately 1.4 MDa multi-protein complex that transports many cellular cargoes towards the minus ends of microtubules. Several in vitro studies of mammalian dynein have suggested that individual motors are not robustly processive, raising questions about how dynein-associated cargoes can move over long distances in cells. Here, we report the production of a fully recombinant human dynein complex from a single baculovirus in insect cells. Individual complexes very rarely show directional movement in vitro. However, addition of dynactin together with the N-terminal region of the cargo adaptor BICD2 (BICD2N) gives rise to unidirectional dynein movement over remarkably long distances. Single-molecule fluorescence microscopy provides evidence that BICD2N and dynactin stimulate processivity by regulating individual dynein complexes, rather than by promoting oligomerisation of the motor complex. Negative stain electron microscopy reveals the dynein–dynactin–BICD2N complex to be well ordered, with dynactin positioned approximately along the length of the dynein tail. Collectively, our results provide insight into a novel mechanism for coordinating cargo binding with long-distance motor movement.
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Affiliation(s)
- Max A Schlager
- Division of Structural Studies, MRC-Laboratory of Molecular Biology, Cambridge, UK
| | - Ha Thi Hoang
- Division of Cell Biology, MRC-Laboratory of Molecular Biology, Cambridge, UK
| | - Linas Urnavicius
- Division of Structural Studies, MRC-Laboratory of Molecular Biology, Cambridge, UK
| | - Simon L Bullock
- Division of Cell Biology, MRC-Laboratory of Molecular Biology, Cambridge, UK
| | - Andrew P Carter
- Division of Structural Studies, MRC-Laboratory of Molecular Biology, Cambridge, UK
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Granger E, McNee G, Allan V, Woodman P. The role of the cytoskeleton and molecular motors in endosomal dynamics. Semin Cell Dev Biol 2014; 31:20-9. [PMID: 24727350 PMCID: PMC4071412 DOI: 10.1016/j.semcdb.2014.04.011] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/01/2014] [Accepted: 04/03/2014] [Indexed: 12/28/2022]
Abstract
The endocytic pathway is essential for processes that define how cells interact with their environment, including receptor signalling, cell adhesion and migration, pathogen entry, membrane protein turnover and nutrient uptake. The spatial organisation of endocytic trafficking requires motor proteins that tether membranes or transport them along the actin and microtubule cytoskeletons. Microtubules, actin filaments and motor proteins also provide force to deform and assist in the scission of membranes, thereby facilitating endosomal sorting and the generation of transport intermediates.
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Affiliation(s)
- Elizabeth Granger
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Gavin McNee
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Victoria Allan
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
| | - Philip Woodman
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
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15
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Mazel T, Biesemann A, Krejczy M, Nowald J, Müller O, Dehmelt L. Direct observation of microtubule pushing by cortical dynein in living cells. Mol Biol Cell 2013; 25:95-106. [PMID: 24173713 PMCID: PMC3873897 DOI: 10.1091/mbc.e13-07-0376] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Single-molecule speckle microscopy and computational modeling reveal the relation between cortical dynein complex dynamics and microtubule behavior in mammalian cells. Experimentally observed rapid turnover of dynein complexes at the cell cortex facilitates their search to efficiently capture and push microtubules with leading plus ends. Microtubules are under the influence of forces mediated by cytoplasmic dynein motors associated with the cell cortex. If such microtubules are free to move, they are rapidly transported inside cells. Here we directly observe fluorescent protein–labeled cortical dynein speckles and motile microtubules. We find that several dynein complex subunits, including the heavy chain, the intermediate chain, and the associated dynactin subunit Dctn1 (also known as p150glued) form spatially resolved, dynamic speckles at the cell cortex, which are preferentially associated with microtubules. Measurements of bleaching and dissociation kinetics at the cell cortex reveal that these speckles often contain multiple labeled dynein heavy-chain molecules and turn over rapidly within seconds. The dynamic behavior of microtubules, such as directional movement, bending, or rotation, is influenced by association with dynein speckles, suggesting a direct physical and functional interaction. Our results support a model in which rapid turnover of cell cortex–associated dynein complexes facilitates their search to efficiently capture and push microtubules directionally with leading plus ends.
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Affiliation(s)
- Tomáš Mazel
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, and Fakultät Chemie, Chemische Biologie, Dortmund University of Technology, 44227 Dortmund, Germany
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Lazarus JE, Moughamian AJ, Tokito MK, Holzbaur ELF. Dynactin subunit p150(Glued) is a neuron-specific anti-catastrophe factor. PLoS Biol 2013; 11:e1001611. [PMID: 23874158 PMCID: PMC3712912 DOI: 10.1371/journal.pbio.1001611] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 05/31/2013] [Indexed: 01/25/2023] Open
Abstract
The dynein partner dynactin not only binds to microtubules, but is found to potently influence microtubule dynamics in neurons. Regulation of microtubule dynamics in neurons is critical, as defects in the microtubule-based transport of axonal organelles lead to neurodegenerative disease. The microtubule motor cytoplasmic dynein and its partner complex dynactin drive retrograde transport from the distal axon. We have recently shown that the p150Glued subunit of dynactin promotes the initiation of dynein-driven cargo motility from the microtubule plus-end. Because plus end-localized microtubule-associated proteins like p150Glued may also modulate the dynamics of microtubules, we hypothesized that p150Glued might promote cargo initiation by stabilizing the microtubule track. Here, we demonstrate in vitro using assembly assays and TIRF microscopy, and in primary neurons using live-cell imaging, that p150Glued is a potent anti-catastrophe factor for microtubules. p150Glued alters microtubule dynamics by binding both to microtubules and to tubulin dimers; both the N-terminal CAP-Gly and basic domains of p150Glued are required in tandem for this activity. p150Glued is alternatively spliced in vivo, with the full-length isoform including these two domains expressed primarily in neurons. Accordingly, we find that RNAi of p150Glued in nonpolarized cells does not alter microtubule dynamics, while depletion of p150Glued in neurons leads to a dramatic increase in microtubule catastrophe. Strikingly, a mutation in p150Glued causal for the lethal neurodegenerative disorder Perry syndrome abrogates this anti-catastrophe activity. Thus, we find that dynactin has multiple functions in neurons, both activating dynein-mediated retrograde axonal transport and enhancing microtubule stability through a novel anti-catastrophe mechanism regulated by tissue-specific isoform expression; disruption of either or both of these functions may contribute to neurodegenerative disease. Microtubules are polymers of tubulin that undergo successive cycles of growth and shrinkage so that the cell can maintain a stable yet adaptable cytoskeleton. In neurons, the microtubule motor protein dynein and its partner complex dynactin drive retrograde transport along microtubules from the distal axon towards the cell body. In addition to binding to dynein, the p150Glued subunit of dynactin independently binds directly to microtubules. We hypothesized that by binding to microtubules, p150Glued might also alter microtubule dynamics. We demonstrate using biochemistry and microscopy in vitro and in cells that p150Glued stabilizes microtubules by inhibiting the transition from growth to shrinkage. We show that specific domains of p150Glued encoded by neuronally enriched splice-forms are necessary for this activity. Although depletion of p150Glued in nonpolarized cells does not alter microtubule dynamics, depletion of endogenous p150Glued in neurons leads to dramatic microtubule instability. Strikingly, a mutation in p150Glued known to cause the neurodegenerative disorder Perry syndrome abolishes this activity. In summary, we identified a previously unappreciated function of dynactin in direct regulation of the microtubule cytoskeleton. This activity may enhance generic microtubule stability in the cell, but could be especially important in specific areas of the cell where dynactin and dynein are loaded onto microtubules.
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Affiliation(s)
- Jacob E. Lazarus
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Armen J. Moughamian
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Mariko K. Tokito
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Erika L. F. Holzbaur
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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18
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Zhao X, Kumar P, Shah-Simpson S, Caradonna KL, Galjart N, Teygong C, Blader I, Wittmann T, Burleigh BA. Host microtubule plus-end binding protein CLASP1 influences sequential steps in the Trypanosoma cruzi infection process. Cell Microbiol 2012; 15:571-84. [PMID: 23107073 DOI: 10.1111/cmi.12056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 10/08/2012] [Accepted: 10/11/2012] [Indexed: 12/14/2022]
Abstract
Mammalian cell invasion by the protozoan parasite Trypanosoma cruzi involves host cell microtubule dynamics. Microtubules support kinesin-dependent anterograde trafficking of host lysosomes to the cell periphery where targeted lysosome exocytosis elicits remodelling of the plasma membrane and parasite invasion. Here, a novel role for microtubule plus-end tracking proteins (+TIPs) in the co-ordination of T. cruzi trypomastigote internalization and post-entry events is reported. Acute silencing of CLASP1, a +TIP that participates in microtubule stabilization at the cell periphery, impairs trypomastigote internalization without diminishing the capacity for calcium-regulated lysosome exocytosis. Subsequent fusion of the T. cruzi vacuole with host lysosomes and its juxtanuclear positioning are also delayed in CLASP1-depleted cells. These post-entry phenotypes correlate with a generalized impairment of minus-end directed transport of lysosomes in CLASP1 knock-down cells and mimic the effects of dynactin disruption. Consistent with GSK3β acting as a negative regulator of CLASP function, inhibition of GSK3β activity enhances T. cruzi entry in a CLASP1-dependent manner and expression of constitutively active GSK3β dampens infection. This study provides novel molecular insights into the T. cruzi infection process, emphasizing functional links between parasite-elicited signalling, host microtubule plus-end tracking proteins and dynein-based retrograde transport. Highlighted in this work is a previously unrecognized role for CLASPs in dynamic lysosome positioning, an important aspect of the nutrient sensing response in mammalian cells.
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Affiliation(s)
- Xiaoyan Zhao
- Department of Immunology and Infectious Disease, Harvard School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA
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19
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Splinter D, Razafsky DS, Schlager MA, Serra-Marques A, Grigoriev I, Demmers J, Keijzer N, Jiang K, Poser I, Hyman AA, Hoogenraad CC, King SJ, Akhmanova A. BICD2, dynactin, and LIS1 cooperate in regulating dynein recruitment to cellular structures. Mol Biol Cell 2012; 23:4226-41. [PMID: 22956769 PMCID: PMC3484101 DOI: 10.1091/mbc.e12-03-0210] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study dissects the recruitment of dynein and dynactin to cargo by a conserved motor adaptor BICD2. It is shown that dynein, dynactin, and BICD2 form a triple complex in vitro and in vivo. Investigation of the properties of this complex by direct visualization of dynein in live cells shows that BICD2-induced dynein transport requires LIS1. Cytoplasmic dynein is the major microtubule minus-end–directed cellular motor. Most dynein activities require dynactin, but the mechanisms regulating cargo-dependent dynein–dynactin interaction are poorly understood. In this study, we focus on dynein–dynactin recruitment to cargo by the conserved motor adaptor Bicaudal D2 (BICD2). We show that dynein and dynactin depend on each other for BICD2-mediated targeting to cargo and that BICD2 N-terminus (BICD2-N) strongly promotes stable interaction between dynein and dynactin both in vitro and in vivo. Direct visualization of dynein in live cells indicates that by itself the triple BICD2-N–dynein–dynactin complex is unable to interact with either cargo or microtubules. However, tethering of BICD2-N to different membranes promotes their microtubule minus-end–directed motility. We further show that LIS1 is required for dynein-mediated transport induced by membrane tethering of BICD2-N and that LIS1 contributes to dynein accumulation at microtubule plus ends and BICD2-positive cellular structures. Our results demonstrate that dynein recruitment to cargo requires concerted action of multiple dynein cofactors.
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Affiliation(s)
- Daniël Splinter
- Department of Cell Biology, Erasmus Medical Centre, 3000 CA Rotterdam, Netherlands Department of Neuroscience, Erasmus Medical Centre, 3000 CA Rotterdam, The Netherlands
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20
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Lloyd TE, Machamer J, O'Hara K, Kim JH, Collins SE, Wong MY, Sahin B, Imlach W, Yang Y, Levitan ES, McCabe BD, Kolodkin AL. The p150(Glued) CAP-Gly domain regulates initiation of retrograde transport at synaptic termini. Neuron 2012; 74:344-60. [PMID: 22542187 DOI: 10.1016/j.neuron.2012.02.026] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2012] [Indexed: 12/15/2022]
Abstract
p150(Glued) is the major subunit of dynactin, a complex that functions with dynein in minus-end-directed microtubule transport. Mutations within the p150(Glued) CAP-Gly microtubule-binding domain cause neurodegenerative diseases through an unclear mechanism. A p150(Glued) motor neuron degenerative disease-associated mutation introduced into the Drosophila Glued locus generates a partial loss-of-function allele (Gl(G38S)) with impaired neurotransmitter release and adult-onset locomotor dysfunction. Disruption of the p150(Glued) CAP-Gly domain in neurons causes a specific disruption of vesicle trafficking at terminal boutons (TBs), the distal-most ends of synapses. Gl(G38S) larvae accumulate endosomes along with dynein and kinesin motor proteins within swollen TBs, and genetic analyses show that kinesin and p150(Glued) function cooperatively at TBs to coordinate transport. Therefore, the p150(Glued) CAP-Gly domain regulates dynein-mediated retrograde transport at synaptic termini, and this function of dynactin is disrupted by a mutation that causes motor neuron disease.
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Affiliation(s)
- Thomas E Lloyd
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Abstract
Vigorous transport of cytoplasmic components along axons over substantial distances is crucial for the maintenance of neuron structure and function. The transport of mitochondria, which serves to distribute mitochondrial functions in a dynamic and non-uniform fashion, has attracted special interest in recent years following the discovery of functional connections among microtubules, motor proteins and mitochondria, and their influences on neurodegenerative diseases. Although the motor proteins that drive mitochondrial movement are now well characterized, the mechanisms by which anterograde and retrograde movement are coordinated with one another and with stationary axonal mitochondria are not yet understood. In this Commentary, we review why mitochondria move and how they move, focusing particularly on recent studies of transport regulation, which implicate control of motor activity by specific cell-signaling pathways, regulation of motor access to transport tracks and static microtubule-mitochondrion linkers. A detailed mechanism for modulating anterograde mitochondrial transport has been identified that involves Miro, a mitochondrial Ca(2+)-binding GTPase, which with associated proteins, can bind and control kinesin-1. Elements of the Miro complex also have important roles in mitochondrial fission-fusion dynamics, highlighting questions about the interdependence of biogenesis, transport, dynamics, maintenance and degradation.
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Affiliation(s)
- William M Saxton
- Department of Molecular Cell and Developmental Biology, University of California, Cruz, CA 95060, USA.
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22
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Abstract
Microtubule motor proteins play key roles in the spatial organization of intracellular organelles as well as the transfer of material between them. This is well illustrated both by the vectorial transfer of biosynthetic cargo from the endoplasmic reticulum to the Golgi apparatus as well as the sorting of secretory and endocytic cargo in the endosomal system. Roles have been described for dynein and kinesin motors in each of these steps. Cytoplasmic dynein is a highly complex motor comprising multiple subunits that provide functional specialization. The family of human kinesins includes over 40 members. This complexity provides immense functional diversity, yet little is known of the specific requirements and functions of individual motors during discrete membrane trafficking steps. In the present paper, we describe some of the latest findings in this area that seek to define the mechanisms of recruitment and control of activity of microtubule motors in spatial organization and cargo trafficking through the endosomal network.
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The native structure of cytoplasmic dynein at work translocating vesicles in Paramecium. Eur J Cell Biol 2011; 90:81-92. [DOI: 10.1016/j.ejcb.2010.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 08/11/2010] [Accepted: 08/16/2010] [Indexed: 11/20/2022] Open
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Tan SC, Scherer J, Vallee RB. Recruitment of dynein to late endosomes and lysosomes through light intermediate chains. Mol Biol Cell 2010; 22:467-77. [PMID: 21169557 PMCID: PMC3038645 DOI: 10.1091/mbc.e10-02-0129] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cytoplasmic dynein is involved in a wide range of cellular processes, but how it is regulated and how it recognizes an extremely wide range of cargo are incompletely understood. The dynein light intermediate chains, LIC1 and LIC2 (DYNC1LI1 and DYNC1LI2, respectively), have been implicated in cargo binding, but their full range of functions is unknown. Using LIC isoform-specific antibodies, we report the first characterization of their subcellular distribution and identify a specific association with elements of the late endocytic pathway, but not other vesicular compartments. LIC1 and LIC2 RNA interference (RNAi) each specifically disrupts the distribution of lysosomes and late endosomes. Stimulation of dynein-mediated late-endosomal transport by the Rab7-interacting lysosomal protein (RILP) is reversed by LIC1 RNAi, which displaces dynein, but not dynactin, from these structures. Conversely, expression of ΔN-RILP or the dynactin subunit dynamitin each fails to displace dynein, but not dynactin. Thus, using a variety of complementary approaches, our results indicate a novel specific role for the LICs in dynein recruitment to components of the late endocytic pathway.
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Affiliation(s)
- Serena C Tan
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Morel M, Authelet M, Dedecker R, Brion J. Glycogen synthase kinase-3β and the p25 activator of cyclin dependent kinase 5 increase pausing of mitochondria in neurons. Neuroscience 2010; 167:1044-56. [DOI: 10.1016/j.neuroscience.2010.02.077] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 02/26/2010] [Accepted: 02/28/2010] [Indexed: 01/01/2023]
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Palmer KJ, Hughes H, Stephens DJ. Specificity of cytoplasmic dynein subunits in discrete membrane-trafficking steps. Mol Biol Cell 2009; 20:2885-99. [PMID: 19386764 DOI: 10.1091/mbc.e08-12-1160] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The cytoplasmic dynein motor complex is known to exist in multiple forms, but few specific functions have been assigned to individual subunits. A key limitation in the analysis of dynein in intact mammalian cells has been the reliance on gross perturbation of dynein function, e.g., inhibitory antibodies, depolymerization of the entire microtubule network, or the use of expression of dominant negative proteins that inhibit dynein indirectly. Here, we have used RNAi and automated image analysis to define roles for dynein subunits in distinct membrane-trafficking processes. Depletion of a specific subset of dynein subunits, notably LIC1 (DYNC1LI1) but not LIC2 (DYNC1LI2), recapitulates a direct block of ER export, revealing that dynein is required to maintain the steady-state composition of the Golgi, through ongoing ER-to-Golgi transport. Suppression of LIC2 but not of LIC1 results in a defect in recycling endosome distribution and cytokinesis. Biochemical analyses also define the role of each subunit in stabilization of the dynein complex; notably, suppression of DHC1 or IC2 results in concomitant loss of Tctex1. Our data demonstrate that LIC1 and LIC2 define distinct dynein complexes that function at the Golgi versus recycling endosomes, respectively, suggesting that functional populations of dynein mediate discrete intracellular trafficking pathways.
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Affiliation(s)
- Krysten J Palmer
- Cell Biology Laboratories, Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS81TD, United Kingdom
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Abstract
Mitochondrial dynamics and transport have emerged as key factors in the regulation of neuronal differentiation and survival. Mitochondria are dynamically transported in and out of axons and dendrites to maintain neuronal and synaptic function. Transport proceeds through a controlled series of plus- and minus-end directed movements along microtubule tracks (MTs) that are often interrupted by short stops. This bidirectional motility of mitochondria is facilitated by plus end-directed kinesin and minus end-directed dynein motors, and may be coordinated and controlled by a number of mechanisms that integrate intracellular signals to ensure efficient transport and targeting of mitochondria. In this chapter, we discuss our understanding of mechanisms that facilitate mitochondrial transport and delivery to specific target sites in dendrites and axons.
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Ha J, Lo KWH, Myers KR, Carr TM, Humsi MK, Rasoul BA, Segal RA, Pfister KK. A neuron-specific cytoplasmic dynein isoform preferentially transports TrkB signaling endosomes. ACTA ACUST UNITED AC 2008; 181:1027-39. [PMID: 18559670 PMCID: PMC2426944 DOI: 10.1083/jcb.200803150] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cytoplasmic dynein is the multisubunit motor protein for retrograde movement of diverse cargoes to microtubule minus ends. Here, we investigate the function of dynein variants, defined by different intermediate chain (IC) isoforms, by expressing fluorescent ICs in neuronal cells. Green fluorescent protein (GFP)-IC incorporates into functional dynein complexes that copurify with membranous organelles. In living PC12 cell neurites, GFP-dynein puncta travel in both the anterograde and retrograde directions. In cultured hippocampal neurons, neurotrophin receptor tyrosine kinase B (TrkB) signaling endosomes are transported by cytoplasmic dynein containing the neuron-specific IC-1B isoform and not by dynein containing the ubiquitous IC-2C isoform. Similarly, organelles containing TrkB isolated from brain by immunoaffinity purification also contain dynein with IC-1 but not IC-2 isoforms. These data demonstrate that the IC isoforms define dynein populations that are selectively recruited to transport distinct cargoes.
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Affiliation(s)
- Junghoon Ha
- Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
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29
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Loubéry S, Wilhelm C, Hurbain I, Neveu S, Louvard D, Coudrier E. Different microtubule motors move early and late endocytic compartments. Traffic 2008; 9:492-509. [PMID: 18194411 DOI: 10.1111/j.1600-0854.2008.00704.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Important progress has been made during the past decade in the identification of molecular motors required in the distribution of early and late endosomes and the proper trafficking along the endocytic pathway. There is little direct evidence, however, that these motors drive movement of the endosomes. To evaluate the contributions of kinesin-1, dynein and kinesin-2 to the movement of early and late endosomes along microtubules, we made use of a cytosol-free motility assay using magnetically isolated early and late endosomes as well as biochemical analyses and live-cell imaging. By making use of specific antibodies, we confirmed that kinesin-1 and dynein move early endosomes and we found that kinesin-2 moves both early and late endosomes in the cell-free assay. Unexpectedly, dynein did not move late endosomes in the cell-free assay. We provide evidence from disruption of dynein function and latrunculin A treatment, suggesting that dynein regulates late endosome movement indirectly, possibly through a mechanism involving the actin cytoskeleton. These data provide new insights into the complex regulation of endosomes' motility and suggest that dynein is not the major motor required to move late endosomes toward the minus end of microtubules.
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Ateh DD, Hussain IK, Mustafa AH, Price KM, Gulati R, Nickols CD, Bird MM, Greensmith L, Hafezparast M, Fisher EMC, Baker CS, Martin JE. Dynein-dynactin complex subunits are differentially localized in brain and spinal cord, with selective involvement in pathological features of neurodegenerative disease. Neuropathol Appl Neurobiol 2007; 34:88-94. [DOI: 10.1111/j.1365-2990.2007.00924.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Abstract
The role of cholesterol in the regulation of endosome motility was investigated by monitoring the intracellular trafficking of endocytosed folate receptors (FRs) labeled with fluorescent folate conjugates. Real-time fluorescence imaging of HeLa cells transfected with green fluorescent protein-tubulin revealed that FR-containing endosomes migrate along microtubules. Moreover, microinjection with antibodies that inhibit microtubule-associated motor proteins demonstrated that dynein and kinesin I participate in the delivery of FR-containing endosomes to the perinuclear area and plasma membrane, respectively. Further, single-particle tracking analysis revealed bidirectional motions of FR endosomes, mediated by dynein and kinesin motors associated with the same endosome. These experimental tools allowed us to use FR-containing endosomes to evaluate the impact of cholesterol on intracellular membrane trafficking. Lowering plasma membrane cholesterol by metabolic depletion or methyl-beta-cyclodextrin extraction was found to both increase FR-containing endosome motility and change endosome distribution from colocalization with Rab7 to colocalization with Rab4. These data provide evidence that cholesterol regulates intracellular membrane trafficking via modulation of the distribution of low molecular weight G-proteins that are adaptors for microtubule motors.
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Byers HR, Dykstra SG, Boissel SJS. Requirement of Dynactin p150Glued Subunit for the Functional Integrity of the Keratinocyte Microparasol. J Invest Dermatol 2007; 127:1736-44. [PMID: 17344930 DOI: 10.1038/sj.jid.5700760] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The keratinocyte microparasol, composed of a perinuclear microtubular/melano-phagolysosomal complex, protects the nucleus from UV-induced DNA damage. We have previously demonstrated that cytoplasmic dynein is the motor involved in the perinuclear-directed aggregation of phagocytosed melanosomes. Dynactin, of which p150(Glued) is the major subunit, can link directly to microtubules and links organelles to dynein at different domains. To further define the mechanism of the microparasol, we transfected siRNA targeted against p150(Glued) into human keratinocytes cultured with 0.5 mm fluorescent microspheres and performed time-lapse analysis, confocal immunolocalization, and Western immunoblotting after 24 and 48 hours. Western blots revealed a significant knockdown of the p150(Glued) subunit. The knockdown decreased p150(Glued) colocalization with microtubules and decreased perinuclear positioning of the convergent microtubular framework. It also inhibited perinuclear aggregation of phagocytosed fluorescent microspheres and reduced mean centripetal microsphere displacement. The findings provide evidence that dynactin p150(Glued) plays an important role in the functional integrity of the keratinocyte microparasol.
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Affiliation(s)
- H Randolph Byers
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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Abstract
Molecular motor proteins are crucial for the proper distribution of organelles and vesicles in cells. Much of our current understanding of how motors function stems from studies of single motors moving cargos in vitro. More recently, however, there has been mounting evidence that the cooperation of multiple motors in moving cargos and the regulation of motor-filament affinity could be key mechanisms that cells utilize to regulate cargo transport. Here, we review these recent advances and present a picture of how the different mechanisms of regulating the number of motors moving a cargo could facilitate cellular functions.
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Affiliation(s)
- Steven P Gross
- Department of Developmental and Cell Biology, 2222 Nat Sci I, University of California Irvine, Irvine, California, USA.
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A microtubule-based, dynein-dependent force induces local cell protrusions: Implications for neurite initiation. ACTA ACUST UNITED AC 2007; 35:39-56. [PMID: 17940912 DOI: 10.1007/s11068-006-9001-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 10/26/2006] [Accepted: 11/15/2006] [Indexed: 10/23/2022]
Abstract
A key event in neurite initiation is the accumulation of microtubule bundles at the neuron periphery. We hypothesized that such bundled microtubules may generate a force at the plasma membrane that facilitates neurite initiation. To test this idea we observed the behavior of microtubule bundles that were induced by the microtubule-associated protein MAP2c. Endogenous MAP2c contributes to neurite initiation in primary neurons, and exogeneous MAP2c is sufficient to induce neurites in Neuro-2a cells. We performed nocodazol washout experiments in primary neurons, Neuro-2a cells and COS-7 cells to investigate the underlying mechanism. During nocodazol washout, small microtubule bundles formed rapidly in the cytoplasm and immediately began to move toward the cell periphery in a unidirectional manner. In neurons and Neuro-2a cells, neurite-like processes extended within minutes and concurrently accumulated bundles of repolymerized microtubules. Speckle microscopy in COS-7 cells indicated that bundle movement was due to transport, not treadmilling. At the periphery bundles remained under a unidirectional force and induced local cell protrusions that were further enhanced by suppression of Rho kinase activity. Surprisingly, this bundle motility was independent of classical actin- or microtubule-based tracks. It was, however, reversed by function-blocking antibodies against dynein. Suppression of dynein expression in primary neurons by RNA interference severely inhibited the generation of new neurites, but not the elongation of existing neurites formed prior to dynein knockdown. Together, these cell biological data suggest that neuronal microtubule-associated proteins induce microtubule bundles that are pushed outward by dynein and locally override inward contraction to initiate neurite-like cell protrusions. A similar force-generating mechanism might participate in spontaneous initiation of neurites in developing neurons.
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Burakov AV, Nadezhdina ES. Dynein and dynactin as organizers of the system of cell microtubules. Russ J Dev Biol 2006. [DOI: 10.1134/s1062360406050018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Mallik R, Petrov D, Lex SA, King SJ, Gross SP. Building complexity: an in vitro study of cytoplasmic dynein with in vivo implications. Curr Biol 2006; 15:2075-85. [PMID: 16332532 DOI: 10.1016/j.cub.2005.10.039] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 10/12/2005] [Accepted: 10/14/2005] [Indexed: 01/02/2023]
Abstract
BACKGROUND Cytoplasmic dynein is the molecular motor responsible for most retrograde microtubule-based vesicular transport. In vitro single-molecule experiments suggest that dynein function is not as robust as that of kinesin-1 or myosin-V because dynein moves only a limited distance (approximately 800 nm) before detaching and can exert a modest (approximately 1 pN) force. However, dynein-driven cargos in vivo move robustly over many microns and exert forces of multiple pN. To determine how to go from limited single-molecule function to robust in vivo transport, we began to build complexity in a controlled manner by using in vitro experiments. RESULTS We show that a single cytoplasmic dynein motor frequently transitions into an off-pathway unproductive state that impairs net transport. Addition of a second (and/or third) dynein motor, so that cargos are moved by two (or three) motors rather than one, is sufficient to recover several properties of in vivo motion; such properties include long cargo travels, robust motion, and increased forces. Part of this improvement appears to arise from selective suppression of the unproductive state of dynein rather than from a fundamental change in dynein's mechanochemical cycle. CONCLUSIONS Multiple dyneins working together suppress shortcomings of a single motor and generate robust motion under in vitro conditions. There appears to be no need for additional cofactors (e.g., dynactin) for this improvement. Because cargos are often driven by multiple dyneins in vivo, our results show that changing the number of dynein motors could allow modulation of dynein function from the mediocre single-dynein limit to robust in vivo-like dynein-driven motion.
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Affiliation(s)
- Roop Mallik
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, California 92697, USA
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Watson P, Stephens DJ. Microtubule plus-end loading of p150(Glued) is mediated by EB1 and CLIP-170 but is not required for intracellular membrane traffic in mammalian cells. J Cell Sci 2006; 119:2758-67. [PMID: 16772339 PMCID: PMC1630633 DOI: 10.1242/jcs.02999] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microtubule dynamics and function are regulated, at least in part, by a family of proteins that localize to microtubule plus-ends, and include EB1, CLIP-170 and the dynactin component p150(Glued). Plus-end pools of these proteins, notably dynactin, have been invoked in a number of ;search-and-capture' mechanisms, including the attachment of microtubules to kinetochores during mitosis and to endomembranes prior to the initiation of intracellular transport. Here we show that, in mammalian cells, EB1 is required for the plus-end localization of CLIP-170, and that this is in turn required to localize p150(Glued) to plus-ends. Specific depletion of CLIP-170 results in defects in microtubule dynamics, cell polarization in response to scratch wounding and a loss of p150(Glued) from plus ends. By contrast, removal of p150(Glued) from plus-ends by depletion of either EB1 or CLIP-170 caused no defects in the localization of intracellular organelles, the dynamics of ER-to-Golgi transport, the efficiency of transferrin uptake or the motility of early endosomes or lysosomes. In addition to labelling microtubule plus-ends, we show that GFP-p150(Glued) becomes incorporated into the dynactin complex and labels small, highly dynamic, punctate structures that move along microtubules. A subset of these structures colocalizes with ER-Golgi transport intermediates. Together, these data show that the function of CLIP-170 and p150(Glued) in membrane trafficking is not associated with their plus-end localization.
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Abstract
Organelle transport is vital for the development and maintenance of axons, in which the distances between sites of organelle biogenesis, function, and recycling or degradation can be vast. Movement of mitochondria in axons can serve as a general model for how all organelles move: mitochondria are easy to identify, they move along both microtubule and actin tracks, they pause and change direction, and their transport is modulated in response to physiological signals. However, they can be distinguished from other axonal organelles by the complexity of their movement and their unique functions in aerobic metabolism, calcium homeostasis and cell death. Mitochondria are thus of special interest in relating defects in axonal transport to neuropathies and degenerative diseases of the nervous system. Studies of mitochondrial transport in axons are beginning to illuminate fundamental aspects of the distribution mechanism. They use motors of one or more kinesin families, along with cytoplasmic dynein, to translocate along microtubules, and bidirectional movement may be coordinated through interaction between dynein and kinesin-1. Translocation along actin filaments is probably driven by myosin V, but the protein(s) that mediate docking with actin filaments remain unknown. Signaling through the PI 3-kinase pathway has been implicated in regulation of mitochondrial movement and docking in the axon, and additional mitochondrial linker and regulatory proteins, such as Milton and Miro, have recently been described.
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Affiliation(s)
- Peter J Hollenbeck
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907, USA.
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Shang T, Joseph J, Hillard CJ, Kalyanaraman B. Death-associated Protein Kinase as a Sensor of Mitochondrial Membrane Potential. J Biol Chem 2005; 280:34644-53. [PMID: 16085644 DOI: 10.1074/jbc.m506466200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We have investigated here the mechanism of dephosphorylation and activation of death-associated protein kinase (DAPK) and the role of lysosome in neuroblastoma cells (SH-SY5Y) treated with mitochondrial toxins, such as MPP(+) and rotenone. Mitochondrial respiratory chain inhibitors and uncouplers decreased mitochondrial membrane potential leading to DAPK dephosphorylation and activation. The class III phosphoinositide 3-kinase inhibitors attenuated DAPK dephosphorylation induced by mitochondrial toxins. Complex I inhibition by mitochondrial toxins (e.g. MPP(+)) resulted in mitochondrial swelling and lysosome reduction. Inhibition of class III phosphoinositide 3-kinase attenuated MPP(+)-induced lysosome reduction and cell death. The role of DAPK as a sensor of mitochondrial membrane potential in mitochondrial diseases was addressed.
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Affiliation(s)
- Tiesong Shang
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Vaughan KT. Microtubule plus ends, motors, and traffic of Golgi membranes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1744:316-24. [PMID: 15950296 DOI: 10.1016/j.bbamcr.2005.05.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Revised: 04/30/2005] [Accepted: 05/03/2005] [Indexed: 01/06/2023]
Abstract
The intimate link between microtubule (MT) organization and the components of the secretory pathway has suggested that MT-based motility is an essential component of vesicular membrane transport and membrane polarization. The molecular details of these processes are still under investigation; however, a novel class of MT plus end-binding proteins shed new light on transport between the endoplasmic reticulum (ER) and Golgi apparatus. The dynactin complex, an initial member of this family, shares localization and live-cell imaging phenotypes with other plus end-binding proteins such as CLIP-170 and EB1. In addition, dynactin has been shown to mediate the binding of ER-Golgi transport vesicles to MTs through a regulated MT-binding motif in p150(Glued). Whereas the plus end-binding activity of CLIP-170 and EB1 has been linked to the regulation of dynamic instability, the plus end binding of dynactin is implicated in a search-capture mechanism for dynein-dependent cargoes. An examination of dynactin's role in ER-Golgi transport suggests that plus end binding could be a reflection of fundamental membrane transport mechanisms.
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Affiliation(s)
- Kevin T Vaughan
- Department of Biological Sciences, P.O. Box 369, University of Notre Dame, Notre Dame, IN 46556, USA.
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Li S, Oakley CE, Chen G, Han X, Oakley BR, Xiang X. Cytoplasmic dynein's mitotic spindle pole localization requires a functional anaphase-promoting complex, gamma-tubulin, and NUDF/LIS1 in Aspergillus nidulans. Mol Biol Cell 2005; 16:3591-605. [PMID: 15930134 PMCID: PMC1182300 DOI: 10.1091/mbc.e04-12-1071] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In Aspergillus nidulans, cytoplasmic dynein and NUDF/LIS1 are found at the spindle poles during mitosis, but they seem to be targeted to this location via different mechanisms. The spindle pole localization of cytoplasmic dynein requires the function of the anaphase-promoting complex (APC), whereas that of NUDF does not. Moreover, although NUDF's localization to the spindle poles does not require a fully functional dynein motor, the function of NUDF is important for cytoplasmic dynein's targeting to the spindle poles. Interestingly, a gamma-tubulin mutation, mipAR63, nearly eliminates the localization of cytoplasmic dynein to the spindle poles, but it has no apparent effect on NUDF's spindle pole localization. Live cell analysis of the mipAR63 mutant revealed a defect in chromosome separation accompanied by unscheduled spindle elongation before the completion of anaphase A, suggesting that gamma-tubulin may recruit regulatory proteins to the spindle poles for mitotic progression. In A. nidulans, dynein is not apparently required for mitotic progression. In the presence of a low amount of benomyl, a microtubule-depolymerizing agent, however, a dynein mutant diploid strain exhibits a more pronounced chromosome loss phenotype than the control, indicating that cytoplasmic dynein plays a role in chromosome segregation.
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Affiliation(s)
- Shihe Li
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Abstract
Dynactin is a multisubunit protein complex that is required for most, if not all, types of cytoplasmic dynein activity in eukaryotes. Dynactin binds dynein directly and allows the motor to traverse the microtubule lattice over long distances. A single dynactin subunit, p150Glued, is sufficient for both activities, yet dynactin contains several other subunits that are organized into an elaborate structure. It is currently believed that the bulk of the dynactin structure participates in interactions with a wide range of cellular structures, many of which are cargoes of the dynein motor. Genetic studies verify the importance of all elements of dynactin structure to its function. Although dynein can bind some membranous cargoes independently of dynactin, establishment of a fully functional dynein-cargo link appears to depend on dynactin. In this review, I summarize what is presently known about dynactin structure, the cellular structures with which it associates, and the intermolecular interactions that underlie and regulate binding. Although the molecular details of dynactin's interactions with membranous organelles and other molecules are complex, the framework provided here is intended to distill what is presently known and to be of use to dynactin specialists and beginners alike.
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Affiliation(s)
- Trina A Schroer
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
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Yi M, Weaver D, Hajnóczky G. Control of mitochondrial motility and distribution by the calcium signal: a homeostatic circuit. ACTA ACUST UNITED AC 2004; 167:661-72. [PMID: 15545319 PMCID: PMC2172592 DOI: 10.1083/jcb.200406038] [Citation(s) in RCA: 362] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Mitochondria are dynamic organelles in cells. The control of mitochondrial motility by signaling mechanisms and the significance of rapid changes in motility remains elusive. In cardiac myoblasts, mitochondria were observed close to the microtubular array and displayed both short- and long-range movements along microtubules. By clamping cytoplasmic [Ca2+] ([Ca2+]c) at various levels, mitochondrial motility was found to be regulated by Ca2+ in the physiological range. Maximal movement was obtained at resting [Ca2+]c with complete arrest at 1–2 μM. Movement was fully recovered by returning to resting [Ca2+]c, and inhibition could be repeated with no apparent desensitization. The inositol 1,4,5-trisphosphate– or ryanodine receptor-mediated [Ca2+]c signal also induced a decrease in mitochondrial motility. This decrease followed the spatial and temporal pattern of the [Ca2+]c signal. Diminished mitochondrial motility in the region of the [Ca2+]c rise promotes recruitment of mitochondria to enhance local Ca2+ buffering and energy supply. This mechanism may provide a novel homeostatic circuit in calcium signaling.
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Affiliation(s)
- Muqing Yi
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Abstract
The majority of active transport in the cell is driven by three classes of molecular motors: the kinesin and dynein families that move toward the plus-end and minus-end of microtubules, respectively, and the unconventional myosin motors that move along actin filaments. Each class of motor has different properties, but in the cell they often function together. In this review we summarize what is known about their single-molecule properties and the possibilities for regulation of such properties. In view of new results on cytoplasmic dynein, we attempt to rationalize how these different classes of motors might work together as part of the intracellular transport machinery. We propose that kinesin and myosin are robust and highly efficient transporters, but with somewhat limited room for regulation of function. Because cytoplasmic dynein is less efficient and robust, to achieve function comparable to the other motors it requires a number of accessory proteins as well as multiple dyneins functioning together. This necessity for additional factors, as well as dynein's inherent complexity, in principle allows for greatly increased control of function by taking the factors away either singly or in combination. Thus, dynein's contribution relative to the other motors can be dynamically tuned, allowing the motors to function together differently in a variety of situations.
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Affiliation(s)
- Roop Mallik
- Department of Developmental and Cell Biology, University of California Irvine, California 92697, USA
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45
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Mannick EE, Bonomolo JC, Horswell R, Lentz JJ, Serrano MS, Zapata-Velandia A, Gastanaduy M, Himel JL, Rose SL, Udall JN, Hornick CA, Liu Z. Gene expression in mononuclear cells from patients with inflammatory bowel disease. Clin Immunol 2004; 112:247-57. [PMID: 15308118 DOI: 10.1016/j.clim.2004.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Accepted: 03/17/2004] [Indexed: 01/16/2023]
Abstract
OBJECTIVES Discovery of Nod2 as the inflammatory bowel disease 1 (IBD1) susceptibility gene has brought to light the significance of mononuclear cells in inflammatory bowel disease pathogenesis. The purpose of this study was to examine changes in gene expression in peripheral blood mononuclear cells in patients with untreated Crohn's disease (CD) and ulcerative colitis (UC) as compared to patients with other inflammatory gastrointestinal disorders and to healthy controls. METHODS We used a 2400 gene cDNA glass slide array (MICROMAX) to examine gene expression in peripheral blood mononuclear cells from seven patients with Crohn's disease, five patients with ulcerative colitis, 10 patients with other inflammatory gastrointestinal disorders, and 22 age- and sex-matched controls. Results. Novel categories of genes differentially expressed in Crohn's disease and ulcerative colitis patients included genes regulating hematopoietic cell differentiation and leukemogenesis, lipid raft-associated signaling, the actin cytoskeleton, and vesicular trafficking. CONCLUSIONS Altered gene expression in mononuclear cells may contribute to inflammatory bowel disease pathogenesis.
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Varadi A, Johnson-Cadwell LI, Cirulli V, Yoon Y, Allan VJ, Rutter GA. Cytoplasmic dynein regulates the subcellular distribution of mitochondria by controlling the recruitment of the fission factor dynamin-related protein-1. J Cell Sci 2004; 117:4389-400. [PMID: 15304525 DOI: 10.1242/jcs.01299] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
While the subcellular organisation of mitochondria is likely to influence many aspects of cell physiology, its molecular control is poorly understood. Here, we have investigated the role of the retrograde motor protein complex, dynein-dynactin, in mitochondrial localisation and morphology. Disruption of dynein function, achieved in HeLa cells either by over-expressing the dynactin subunit, dynamitin (p50), or by microinjection of an anti-dynein intermediate chain antibody, resulted in (a) the redistribution of mitochondria to the nuclear periphery, and (b) the formation of long and highly branched mitochondrial structures. Suggesting that an alteration in the balance between mitochondrial fission and fusion may be involved in both of these changes, overexpression of p50 induced the translocation of the fission factor dynamin-related protein (Drp1) from mitochondrial membranes to the cytosol and microsomes. Moreover, a dominant-negative-acting form of Drp1 mimicked the effects of p50 on mitochondrial morphology, while wild-type Drp1 almost completely restored normal mitochondrial distribution in p50 over-expressing cells. Thus, the dynein/dynactin complex plays an unexpected role in the regulation of mitochondrial morphology in living cells, by controlling the recruitment of Drp1 to these organelles.
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Affiliation(s)
- Aniko Varadi
- Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK
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Raj K, Berguerand S, Southern S, Doorbar J, Beard P. E1 empty set E4 protein of human papillomavirus type 16 associates with mitochondria. J Virol 2004; 78:7199-207. [PMID: 15194796 PMCID: PMC421641 DOI: 10.1128/jvi.78.13.7199-7207.2004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The human papillomavirus (HPV) E1 empty set E4 protein is the most abundantly expressed viral protein in HPV-infected epithelia. It possesses diverse activities, including the ability to bind to the cytokeratin network and to DEAD-box proteins, and in some cases induces the collapse of the former. E1 empty set E4 is also able to prevent the progression of cells into mitosis by arresting them in the G(2) phase of the cell cycle. In spite of these intriguing properties, the role of this protein in the life cycle of the virus is not clear. Here we report that after binding to and collapsing the cytokeratin network, the HPV type 16 E1 empty set E4 protein binds to mitochondria. When cytokeratin is not present in the cell, E1 empty set E4 appears associated with mitochondria soon after its synthesis. The leucine cluster within the N-terminal portion of the E1 empty set E4 protein is pivotal in mediating this association. After the initial binding to mitochondria, the E1 empty set E4 protein induces the detachment of mitochondria from microtubules, causing the organelles to form a single large cluster adjacent to the nucleus. This is followed by a severe reduction in the mitochondrial membrane potential and an induction of apoptosis. HPV DNA replication and virion production occur in terminally differentiating cells which are keratin-rich, rigid squamae that exfoliate after completion of the differentiation process. Perturbation of the cytokeratin network and the eventual induction of apoptotic properties are processes that could render these unyielding cells more fragile and ease the exit of newly synthesized HPVs for subsequent rounds of infection.
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Affiliation(s)
- Kenneth Raj
- Swiss Institute for Experimental Cancer Research and NCRR Molecular Oncology, 1066 Epalinges, Switzerland
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48
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Williams SN, Locke CJ, Braden AL, Caldwell KA, Caldwell GA. Epileptic-like convulsions associated with LIS-1 in the cytoskeletal control of neurotransmitter signaling in Caenorhabditis elegans. Hum Mol Genet 2004; 13:2043-59. [PMID: 15254012 DOI: 10.1093/hmg/ddh209] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cortical malformations are a collection of disorders affecting brain development. Mutations in the LIS1 gene lead to a disorganized and smooth cerebral cortex caused by failure in neuronal migration. Among the clinical consequences of lissencephaly are mental retardation and intractable epilepsy. It remains unclear whether the seizures result from aberrant neuronal placement, disruption of intrinsic properties of neurons, or both. The nematode Caenorhabditis elegans offers an opportunity to study such convulsions in a simple animal with a defined nervous system. Here we show that convulsions mimicking epilepsy can be induced by a mutation in a C. elegans lis-1 allele (pnm-1), in combination with a chemical antagonist of gamma-aminobutyric acid (GABA) neurotransmitter signaling. Identical convulsions were obtained using C. elegans mutants defective in GABA transmission, whereas none of these mutants or the antagonist alone caused convulsions, indicating a threshold was exceeded in response to this combination. Crosses between pnm-1 and fluorescent marker strains designed to exclusively illuminate either the processes of GABAergic neurons or synaptic vesicles surprisingly showed no deviations in neuronal architecture. Instead, presynaptic defects in GABAergic vesicle distribution were clearly evident and could be phenocopied by RNAi directed against cytoplasmic dynein, a known LIS1 interactor. Furthermore, mutations in UNC-104, a neuronal-specific kinesin, and SNB-1, a synaptic vesicle-associated protein termed synaptobrevin, exhibit similar convulsion phenotypes following chemical induction. Taken together, these studies establish C. elegans as a system to investigate subtle cytoskeletal mechanisms regulating intrinsic neuronal activity and suggest that it may be possible to dissociate the epileptic consequences of lissencephaly from the more phenotypically overt cortical defects associated with neuronal migration.
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Affiliation(s)
- Shelli N Williams
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487-0344, USA
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49
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Abstract
Active transport is critical for cellular organization and function, and impaired transport has been linked to diseases such as neuronal degeneration. Much long distance transport in cells uses opposite polarity molecular motors of the kinesin and dynein families to move cargos along microtubules. It is increasingly clear that many cargos are moved by both sets of motors, and frequently reverse course. This review compares this bi-directional transport to the more well studied uni-directional transport. It discusses some bi-directionally moving cargos, and critically evaluates three different physical models for how such transport might occur. It then considers the evidence for the number of active motors per cargo, and how the net or average direction of transport might be controlled. The likelihood of a complex linking the activities of kinesin and dynein is also discussed. The paper concludes by reviewing elements of apparent universality between different bi-directionally moving cargos and by briefly considering possible reasons for the existence of bi-directional transport.
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Affiliation(s)
- Steven P Gross
- Department of Developmental and Cell Biology, 2222 Nat. Sci. I, University of California Irvine, Irvine, CA 926976, USA.
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50
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Abstract
Disruption of axonal transport leads to a disorganized distribution of mitochondria and other organelles and is thought to be responsible for some types of neuronal disease. The reason for bidirectional transport of mitochondria is unknown. We have developed and applied a set of statistical methods and found that axonal mitochondria are uniformly distributed. Analysis of fast axonal transport showed that the uniform distribution arose from the clustering of the stopping events of fast axonal transport in the middle of the gaps between stationary mitochondria. To test whether transport was correlated with ATP production, we added metabolic inhibitors locally by micropipette. Whereas applying CCCP (a mitochondrial uncoupler) blocked mitochondrial transport, as has been previously reported, treatment with antimycin (an inhibitor of electron transport at complex III) caused increases in retrograde mitochondrial transport. Application of 2-deoxyglucose did not decrease transport compared with the mannitol control. To determine whether mitochondrial transport was correlated with mitochondrial potential, we stained the neurons with the mitochondrial potential-sensing dye JC-1. We found that approximately 90% of mitochondria with high potential were transported towards the growth cone and approximately 80% of mitochondria with low potential were transported towards the cell body. These experiments show for the first time that a uniform mitochondrial distribution is generated by local regulation of the stopping events of fast mitochondrial transport, and that the direction of mitochondrial transport is correlated with mitochondrial potential. These results have implications for axonal clogging, autophagy, apoptosis and Alzheimer's disease.
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Affiliation(s)
- Kyle E Miller
- Department of Biological Sciences, Room 713 Fairchild Building, Columbia University, New York, NY 10027, USA
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