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Dash B, Dib-Hajj SD, Waxman SG. Multiple myosin motors interact with sodium/potassium-ATPase alpha 1 subunits. Mol Brain 2018; 11:45. [PMID: 30086768 PMCID: PMC6081954 DOI: 10.1186/s13041-018-0388-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/20/2018] [Indexed: 11/10/2022] Open
Abstract
The alpha1 (α1) subunit of the sodium/potassium ATPase (i.e., Na+/K+-ATPase α1), the prototypical sodium pump, is expressed in each eukaryotic cell. They pump out three sodium ions in exchange for two extracellular potassium ions to establish a cellular electrochemical gradient important for firing of neuronal and cardiac action potentials. We hypothesized that myosin (myo or myh) motor proteins might interact with Na+/K+-ATPase α1 subunits in order for them to play an important role in the transport and trafficking of sodium pump. To this end immunoassays were performed to determine whether class II non-muscle myosins (i.e., NMHC-IIA/myh9, NMHC-IIB/myh10 or NMHC-IIC/myh14), myosin Va (myoVa) and myosin VI (myoVI) would interact with Na+/K+-ATPase α1 subunits. Immunoprecipitation of myh9, myh10, myh14, myoVa and myoVI from rat brain tissues led to the co-immunoprecipitation of Na+/K+-ATPase α1 subunits expressed there. Heterologous expression studies using HEK293 cells indicated that recombinant myh9, myh10, myh14 and myoVI interact with Na+/K+-ATPase α1 subunits expressed in HEK293 cells. Additional results indicated that loss of tail regions in recombinant myh9, myh10, myh14 and myoVI did not affect their interaction with Na+/K+-ATPase α1 subunits. However, recombinant myh9, myh10 and myh14 mutants having reduced or no actin binding ability, as a result of loss of their actin binding sites, displayed greatly reduced or null interaction with Na+/K+-ATPase α1 subunits. These results suggested the involvement of the actin binding site, but not tail regions, of NMHC-IIs in their interaction with Na+/K+-ATPase α1 subunits. Overall these results suggest a role for these diverse myosins in the trafficking and transport of sodium pump in neuronal and non-neuronal tissues.
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Affiliation(s)
- Bhagirathi Dash
- Department of Neurology, Yale University Schoolof Medicine, New Haven, CT, 06510, USA.,Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT, 06510, USA.,Rehabilitation Research center, VA Connecticut Healthcare System, 950 Campbell Avenue, Bldg. 34, West Haven, CT, 06516, USA
| | - Sulayman D Dib-Hajj
- Department of Neurology, Yale University Schoolof Medicine, New Haven, CT, 06510, USA.,Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT, 06510, USA.,Rehabilitation Research center, VA Connecticut Healthcare System, 950 Campbell Avenue, Bldg. 34, West Haven, CT, 06516, USA
| | - Stephen G Waxman
- Department of Neurology, Yale University Schoolof Medicine, New Haven, CT, 06510, USA. .,Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT, 06510, USA. .,Rehabilitation Research center, VA Connecticut Healthcare System, 950 Campbell Avenue, Bldg. 34, West Haven, CT, 06516, USA.
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Vallotton P, van Oijen AM, Whitchurch CB, Gelfand V, Yeo L, Tsiavaliaris G, Heinrich S, Dultz E, Weis K, Grünwald D. Diatrack particle tracking software: Review of applications and performance evaluation. Traffic 2017; 18:840-852. [PMID: 28945316 PMCID: PMC5677553 DOI: 10.1111/tra.12530] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 12/24/2022]
Abstract
Object tracking is an instrumental tool supporting studies of cellular trafficking. There are three challenges in object tracking: the identification of targets; the precise determination of their position and boundaries; and the assembly of correct trajectories. This last challenge is particularly relevant when dealing with densely populated images with low signal-to-noise ratios-conditions that are often encountered in applications such as organelle tracking, virus particle tracking or single-molecule imaging. We have developed a set of methods that can handle a wide variety of signal complexities. They are compiled into a free software package called Diatrack. Here we review its main features and utility in a range of applications, providing a survey of the dynamic imaging field together with recommendations for effective use. The performance of our framework is shown to compare favorably to a wide selection of custom-developed algorithms, whether in terms of localization precision, processing speed or correctness of tracks.
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Affiliation(s)
| | | | | | - Vladimir Gelfand
- Northwestern University Feinberg School of Medicine, Department of Cell and Molecular Biology, Chicago, IL 60611, USA
| | | | | | | | - Elisa Dultz
- ETH Zürich, Institute of Biochemistry, Zürich, Switzerland
| | - Karsten Weis
- ETH Zürich, Institute of Biochemistry, Zürich, Switzerland
| | - David Grünwald
- University of Massachusetts Medical School, RNA Therapeutics Institute and Department of Biochemistry and Molecular Pharmacology, Worcester MA, USA
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3
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Cui J, Pang J, Lin YJ, Jiang P, Gong H, Wang Z, Li J, Cai JP, Huang JD, Zhang TM. Conventional kinesin KIF5B mediates adiponectin secretion in 3T3-L1 adipocytes. Biochem Biophys Res Commun 2016; 476:620-626. [DOI: 10.1016/j.bbrc.2016.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 06/02/2016] [Indexed: 01/15/2023]
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Role of Ostm1 Cytosolic Complex with Kinesin 5B in Intracellular Dispersion and Trafficking. Mol Cell Biol 2015; 36:507-21. [PMID: 26598607 DOI: 10.1128/mcb.00656-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/17/2015] [Indexed: 01/05/2023] Open
Abstract
In humans and in mice, mutations in the Ostm1 gene cause the most severe form of osteopetrosis, a major bone disease, and neuronal degeneration, both of which are associated with early death. To gain insight into Ostm1 function, we first investigated by sequence and biochemical analysis an immature 34-kDa type I transmembrane Ostm1 protein with a unique cytosolic tail. Mature Ostm1 is posttranslationally processed and highly N-glycosylated and has an apparent mass of ∼60 kDa. Analysis the subcellular localization of Ostm1 showed that it is within the endoplasmic reticulum, trans-Golgi network, and endosomes/lysosomes. By a wide protein screen under physiologic conditions, several novel cytosolic Ostm1 partners were identified and validated, for which a direct interaction with the kinesin 5B heavy chains was demonstrated. These results determined that Ostm1 is part of a cytosolic scaffolding multiprotein complex, imparting an adaptor function to Ostm1. Moreover, we uncovered a role for the Ostm1/KIF5B complex in intracellular trafficking and dispersion of cargos from the endoplasmic reticulum to late endosomal/lysosomal subcellular compartments. These Ostm1 molecular and cellular functions could elucidate all of the pathophysiologic mechanisms underlying the wide phenotypic spectrum of Ostm1-deficient mice.
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Cui J, Li X, Duan Z, Xue W, Wang Z, Lu S, Lin R, Liu M, Zhu G, Huang JD. Analysis of Kif5b expression during mouse kidney development. PLoS One 2015; 10:e0126002. [PMID: 25885434 PMCID: PMC4401754 DOI: 10.1371/journal.pone.0126002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 03/27/2015] [Indexed: 01/05/2023] Open
Abstract
Recent studies showed that kidney-specific inactivation of Kif3a produces kidney cysts and renal failure, suggesting that kinesin-mediated intracellular transportation is important for the establishement and maintenance of renal epithelial cell polarity and normal nephron functions. Kif5b, one of the most conserved kinesin heavy chain, is the mouse homologue of the human ubiquitous Kinesin Heavy Chain (uKHC). In order to elucidate the role of Kif5b in kidney development and function, it is essential to establish its expression profile within the organ. Therefore, in this study, we examined the expression pattern of Kif5b in mouse kidney. Kidneys from embryonic (E) 12.5-, 16.5-dpc (days post coitus) mouse fetuses, from postnatal (P) day 0, 10, 20 pups and from adult mice were collected. The distribution of Kif5b was analyzed by immunostaining. The possible involvement of Kif5b in kidney development was investigated in conditional mutant mice by using a Cre-LoxP strategy. This study showed that the distribution of Kif5b displayed spatiotemporal changes during postnatal kidney development. In kidneys of new born mice, Kif5b was strongly expressed in all developing tubules and in the ureteric bud, but not in the glomerulus or in other early-developing structures, such as the cap mesenchyme, the comma-shaped body, and the S-shaped body. In kidneys of postnatal day 20 or of older mice, however, Kif5b was localized selectively in the basolateral domain of epithelial cells of the thick ascending loop of Henle, as well as of the distal convoluted tubule, with little expression being observed in the proximal tubule or in the collecting duct. Conditional knock-down of Kif5b in mouse kidney did not result in detectable morphological defects, but it did lead to a decrease in cell proliferation rate and also to a mislocalization of Na+/K+/-ATPase, indicating that although Kif5b is non-essential for kidney morphogenesis, it is important for nephron maturation.
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Affiliation(s)
- Ju Cui
- The Key Laboratory of Geriatrics, Beijing Hospital & Beijing Institute of Geriatrics, Ministry of Health, Beijing, China
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- * E-mail: (JC); (JDH)
| | - Xiuling Li
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Zhigang Duan
- Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Wenqian Xue
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Zai Wang
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, China
| | - Song Lu
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Raozhou Lin
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Mengfei Liu
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Guixia Zhu
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jian-Dong Huang
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- The Centre for Synthetic Biology Engineering Research, Shenzhen Institutes of Advanced Technology, Shenzhen, PR China
- * E-mail: (JC); (JDH)
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von Wangenheim D, Rosero A, Komis G, Šamajová O, Ovečka M, Voigt B, Šamaj J. Endosomal Interactions during Root Hair Growth. FRONTIERS IN PLANT SCIENCE 2015; 6:1262. [PMID: 26858728 PMCID: PMC4731515 DOI: 10.3389/fpls.2015.01262] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/24/2015] [Indexed: 05/21/2023]
Abstract
The dynamic localization of endosomal compartments labeled with targeted fluorescent protein tags is routinely followed by time lapse fluorescence microscopy approaches and single particle tracking algorithms. In this way trajectories of individual endosomes can be mapped and linked to physiological processes as cell growth. However, other aspects of dynamic behavior including endosomal interactions are difficult to follow in this manner. Therefore, we characterized the localization and dynamic properties of early and late endosomes throughout the entire course of root hair formation by means of spinning disc time lapse imaging and post-acquisition automated multitracking and quantitative analysis. Our results show differential motile behavior of early and late endosomes and interactions of late endosomes that may be specified to particular root hair domains. Detailed data analysis revealed a particular transient interaction between late endosomes-termed herein as dancing-endosomes-which is not concluding to vesicular fusion. Endosomes preferentially located in the root hair tip interacted as dancing-endosomes and traveled short distances during this interaction. Finally, sizes of early and late endosomes were addressed by means of super-resolution structured illumination microscopy (SIM) to corroborate measurements on the spinning disc. This is a first study providing quantitative microscopic data on dynamic spatio-temporal interactions of endosomes during root hair tip growth.
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Affiliation(s)
- Daniel von Wangenheim
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of BonnBonn, Germany
| | - Amparo Rosero
- Department of Cell Biology, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký UniversityOlomouc, Czech Republic
| | - George Komis
- Department of Cell Biology, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký UniversityOlomouc, Czech Republic
| | - Olga Šamajová
- Department of Cell Biology, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký UniversityOlomouc, Czech Republic
| | - Miroslav Ovečka
- Department of Cell Biology, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký UniversityOlomouc, Czech Republic
| | - Boris Voigt
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of BonnBonn, Germany
| | - Jozef Šamaj
- Department of Cell Biology, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký UniversityOlomouc, Czech Republic
- *Correspondence: Jozef Šamaj
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7
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Mozola CC, Magassa N, Caparon MG. A novel cholesterol-insensitive mode of membrane binding promotes cytolysin-mediated translocation by Streptolysin O. Mol Microbiol 2014; 94:675-87. [PMID: 25196983 DOI: 10.1111/mmi.12786] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2014] [Indexed: 11/30/2022]
Abstract
Cytolysin-mediated translocation (CMT), performed by Streptococcus pyogenes, utilizes the cholesterol-dependent cytolysin Streptolysin O (SLO) to translocate the NAD(+) -glycohydrolase (SPN) into the host cell during infection. SLO is required for CMT and can accomplish this activity without pore formation, but the details of SLO's interaction with the membrane preceding SPN translocation are unknown. Analysis of binding domain mutants of SLO and binding domain swaps between SLO and homologous cholesterol-dependent cytolysins revealed that membrane binding by SLO is necessary but not sufficient for CMT, demonstrating a specific requirement for SLO in this process. Despite being the only known receptor for SLO, this membrane interaction does not require cholesterol. Depletion of cholesterol from host membranes and mutation of SLO's cholesterol recognition motif abolished pore formation but did not inhibit membrane binding or CMT. Surprisingly, SLO requires the coexpression and membrane localization of SPN to achieve cholesterol-insensitive membrane binding; in the absence of SPN, SLO's binding is characteristically cholesterol-dependent. SPN's membrane localization also requires SLO, suggesting a co-dependent, cholesterol-insensitive mechanism of membrane binding occurs, resulting in SPN translocation.
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Affiliation(s)
- Cara C Mozola
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
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8
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Anderson EN, White JA, Gunawardena S. Axonal transport and neurodegenerative disease: vesicle-motor complex formation and their regulation. Degener Neurol Neuromuscul Dis 2014; 4:29-47. [PMID: 32669899 PMCID: PMC7337264 DOI: 10.2147/dnnd.s57502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/23/2014] [Indexed: 12/12/2022] Open
Abstract
The process of axonal transport serves to move components over very long distances on microtubule tracks in order to maintain neuronal viability. Molecular motors - kinesin and dynein - are essential for the movement of neuronal cargoes along these tracks; defects in this pathway have been implicated in the initiation or progression of some neurodegenerative diseases, suggesting that this process may be a key contributor in neuronal dysfunction. Recent work has led to the identification of some of the motor-cargo complexes, adaptor proteins, and their regulatory elements in the context of disease proteins. In this review, we focus on the assembly of the amyloid precursor protein, huntingtin, mitochondria, and the RNA-motor complexes and discuss how these may be regulated during long-distance transport in the context of neurodegenerative disease. As knowledge of these motor-cargo complexes and their involvement in axonal transport expands, insight into how defects in this pathway contribute to the development of neurodegenerative diseases becomes evident. Therefore, a better understanding of how this pathway normally functions has important implications for early diagnosis and treatment of diseases before the onset of disease pathology or behavior.
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Affiliation(s)
- Eric N Anderson
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Joseph A White
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
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9
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Leikauf GD, Concel VJ, Bein K, Liu P, Berndt A, Martin TM, Ganguly K, Jang AS, Brant KA, Dopico RA, Upadhyay S, Cario C, Di YPP, Vuga LJ, Kostem E, Eskin E, You M, Kaminski N, Prows DR, Knoell DL, Fabisiak JP. Functional genomic assessment of phosgene-induced acute lung injury in mice. Am J Respir Cell Mol Biol 2013; 49:368-83. [PMID: 23590305 DOI: 10.1165/rcmb.2012-0337oc] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In this study, a genetically diverse panel of 43 mouse strains was exposed to phosgene and genome-wide association mapping performed using a high-density single nucleotide polymorphism (SNP) assembly. Transcriptomic analysis was also used to improve the genetic resolution in the identification of genetic determinants of phosgene-induced acute lung injury (ALI). We prioritized the identified genes based on whether the encoded protein was previously associated with lung injury or contained a nonsynonymous SNP within a functional domain. Candidates were selected that contained a promoter SNP that could alter a putative transcription factor binding site and had variable expression by transcriptomic analyses. The latter two criteria also required that ≥10% of mice carried the minor allele and that this allele could account for ≥10% of the phenotypic difference noted between the strains at the phenotypic extremes. This integrative, functional approach revealed 14 candidate genes that included Atp1a1, Alox5, Galnt11, Hrh1, Mbd4, Phactr2, Plxnd1, Ptprt, Reln, and Zfand4, which had significant SNP associations, and Itga9, Man1a2, Mapk14, and Vwf, which had suggestive SNP associations. Of the genes with significant SNP associations, Atp1a1, Alox5, Plxnd1, Ptprt, and Zfand4 could be associated with ALI in several ways. Using a competitive electrophoretic mobility shift analysis, Atp1a1 promoter (rs215053185) oligonucleotide containing the minor G allele formed a major distinct faster-migrating complex. In addition, a gene with a suggestive SNP association, Itga9, is linked to transforming growth factor β1 signaling, which previously has been associated with the susceptibility to ALI in mice.
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Affiliation(s)
- George D Leikauf
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, PA 15219, USA.
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10
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Abstract
Neurons, perhaps more than any other cell type, depend on mitochondrial trafficking for their survival. Recent studies have elucidated a motor/adaptor complex on the mitochondrial surface that is shared between neurons and other animal cells. In addition to kinesin and dynein, this complex contains the proteins Miro (also called RhoT1/2) and milton (also called TRAK1/2) and is responsible for much, although not necessarily all, mitochondrial movement. Elucidation of the complex has permitted inroads for understanding how this movement is regulated by a variety of intracellular signals, although many mysteries remain. Regulating mitochondrial movement can match energy demand to energy supply throughout the extraordinary architecture of these cells and can control the clearance and replenishing of mitochondria in the periphery. Because the extended axons of neurons contain uniformly polarized microtubules, they have been useful for studying mitochondrial motility in conjunction with biochemical assays in many cell types.
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Affiliation(s)
- Thomas L Schwarz
- F.M. Kirby Neurobiology Center, Children's Hospital Boston, and Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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11
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Stephens DJ. Functional coupling of microtubules to membranes - implications for membrane structure and dynamics. J Cell Sci 2012; 125:2795-804. [PMID: 22736043 DOI: 10.1242/jcs.097675] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The microtubule network dictates much of the spatial patterning of the cytoplasm, and the coupling of microtubules to membranes controls the structure and positioning of organelles and directs membrane trafficking between them. The connection between membranes and the microtubule cytoskeleton, and the way in which organelles are shaped and moved by interactions with the cytoskeleton, have been studied intensively in recent years. In particular, recent work has expanded our thinking of this topic to include the mechanisms by which membranes are shaped and how cargo is selected for trafficking as a result of coupling to the cytoskeleton. In this Commentary, I will discuss the molecular basis for membrane-motor coupling and the physiological outcomes of this coupling, including the way in which microtubule-based motors affect membrane structure, cargo sorting and vectorial trafficking between organelles. Whereas many core concepts of these processes are now well understood, key questions remain about how the coupling of motors to membranes is established and controlled, about the regulation of cargo and/or motor loading and about the control of directionality.
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Affiliation(s)
- David J Stephens
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK.
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Hypoxia leads to Na,K-ATPase downregulation via Ca(2+) release-activated Ca(2+) channels and AMPK activation. Mol Cell Biol 2011; 31:3546-56. [PMID: 21730292 DOI: 10.1128/mcb.05114-11] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To maintain cellular ATP levels, hypoxia leads to Na,K-ATPase inhibition in a process dependent on reactive oxygen species (ROS) and the activation of AMP-activated kinase α1 (AMPK-α1). We report here that during hypoxia AMPK activation does not require the liver kinase B1 (LKB1) but requires the release of Ca(2+) from the endoplasmic reticulum (ER) and redistribution of STIM1 to ER-plasma membrane junctions, leading to calcium entry via Ca(2+) release-activated Ca(2+) (CRAC) channels. This increase in intracellular Ca(2+) induces Ca(2+)/calmodulin-dependent kinase kinase β (CaMKKβ)-mediated AMPK activation and Na,K-ATPase downregulation. Also, in cells unable to generate mitochondrial ROS, hypoxia failed to increase intracellular Ca(2+) concentration while a STIM1 mutant rescued the AMPK activation, suggesting that ROS act upstream of Ca(2+) signaling. Furthermore, inhibition of CRAC channel function in rat lungs prevented the impairment of alveolar fluid reabsorption caused by hypoxia. These data suggest that during hypoxia, calcium entry via CRAC channels leads to AMPK activation, Na,K-ATPase downregulation, and alveolar epithelial dysfunction.
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The secretory response of parathyroid hormone to acute hypocalcemia in vivo is independent of parathyroid glandular sodium/potassium-ATPase activity. Kidney Int 2011; 79:742-8. [DOI: 10.1038/ki.2010.501] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Cui J, Wang Z, Cheng Q, Lin R, Zhang XM, Leung PS, Copeland NG, Jenkins NA, Yao KM, Huang JD. Targeted inactivation of kinesin-1 in pancreatic β-cells in vivo leads to insulin secretory deficiency. Diabetes 2011; 60:320-30. [PMID: 20870970 PMCID: PMC3012189 DOI: 10.2337/db09-1078] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Suppression of Kinesin-1 by antisense oligonucleotides, or overexpression of dominant-negative acting kinesin heavy chain, has been reported to affect the sustained phase of glucose-stimulated insulin secretion in β-cells in vitro. In this study, we examined the in vivo physiological role of Kinesin-1 in β-cell development and function. RESEARCH DESIGN AND METHODS A Cre-LoxP strategy was used to generate conditional knockout mice in which the Kif5b gene is specifically inactivated in pancreatic β-cells. Physiological and histological analyses were carried out in Kif5b knockout mice as well as littermate controls. RESULTS Mice with β-cell specific deletion of Kif5b (Kif5b(fl/)⁻:RIP2-Cre) displayed significantly retarded growth as well as slight hyperglycemia in both nonfasting and 16-h fasting conditions compared with control littermates. In addition, Kif5b(fl/)⁻:RIP2-Cre mice displayed significant glucose intolerance, which was not due to insulin resistance but was related to an insulin secretory defect in response to glucose challenge. These defects of β-cell function in mutant mice were not coupled with observable changes in islet morphology, islet cell composition, or β-cell size. However, compared with controls, pancreas of Kif5b(fl/)⁻:RIP2-Cre mice exhibited both reduced islet size and increased islet number, concomitant with an increased insulin vesicle density in β-cells. CONCLUSIONS In addition to being essential for maintaining glucose homeostasis and regulating β-cell function, Kif5b may be involved in β-cell development by regulating β-cell proliferation and insulin vesicle synthesis.
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Affiliation(s)
- Ju Cui
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Zai Wang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Qianni Cheng
- Department of Physiology, The Chinese University of Hong Kong, Hong Kong
| | - Raozhou Lin
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Xin-Mei Zhang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Po Sing Leung
- Department of Physiology, The Chinese University of Hong Kong, Hong Kong
| | - Neal G. Copeland
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Nancy A. Jenkins
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Kwok-Ming Yao
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Corresponding author: Jian-Dong Huang, , or Kwok-Ming Yao,
| | - Jian-Dong Huang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Corresponding author: Jian-Dong Huang, , or Kwok-Ming Yao,
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Chen S, Owens GC, Makarenkova H, Edelman DB. HDAC6 regulates mitochondrial transport in hippocampal neurons. PLoS One 2010; 5:e10848. [PMID: 20520769 PMCID: PMC2877100 DOI: 10.1371/journal.pone.0010848] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 04/26/2010] [Indexed: 12/24/2022] Open
Abstract
Background Tubulin is a major substrate of the cytoplasmic class II histone deacetylase HDAC6. Inhibition of HDAC6 results in higher levels of acetylated tubulin and enhanced binding of the motor protein kinesin-1 to tubulin, which promotes transport of cargoes along microtubules. Microtubule-dependent intracellular trafficking may therefore be regulated by modulating the activity of HDAC6. We have shown previously that the neuromodulator serotonin increases mitochondrial movement in hippocampal neurons via the Akt-GSK3β signaling pathway. Here, we demonstrate a role for HDAC6 in this signaling pathway. Methodology/Principal Findings We found that the presence of tubacin, a specific HDAC6 inhibitor, dramatically enhanced mitochondrial movement in hippocampal neurons, whereas niltubacin, an inactive tubacin analog, had no effect. Compared to control cultures, higher levels of acetylated tubulin were found in neurons treated with tubacin, and more kinesin-1 was associated with mitochondria isolated from these neurons. Inhibition of GSK3β decreased cytoplasmic deacetylase activity and increased tubulin acetylation, whereas blockade of Akt, which phosphorylates and down-regulates GSK3β, increased cytoplasmic deacetylase activity and decreased tubulin acetylation. Concordantly, the administration of 5-HT, 8-OH-DPAT (a specific 5-HT1A receptor agonist), or fluoxetine (a 5-HT reuptake inhibitor) increased tubulin acetylation. GSK3β was found to co-localize with HDAC6 in hippocampal neurons, and inhibition of GSK3β resulted in decreased binding of antibody to phosphoserine-22, a potential GSK3β phosphorylation site in HDAC6. GSK3β may therefore regulate HDAC6 activity by phosphorylation. Conclusions/Significance This study demonstrates that HDAC6 plays an important role in the modulation of mitochondrial transport. The link between HDAC6 and GSK3β, established here, has important implications for our understanding of neurodegenerative disorders. In particular, abnormal mitochondrial transport, which has been observed in such disorders as Alzheimer's disease and Parkinson's disease, could result from the misregulation of HDAC6 by GSK3β. HDAC6 may therefore constitute an attractive target in the treatment of these disorders.
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Affiliation(s)
- Sigeng Chen
- The Neurosciences Institute, San Diego, California, USA.
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