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Li J, Lu Q, Zhang M. Structural Basis of Cargo Recognition by Unconventional Myosins in Cellular Trafficking. Traffic 2016; 17:822-38. [PMID: 26842936 DOI: 10.1111/tra.12383] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/29/2016] [Accepted: 01/29/2016] [Indexed: 01/17/2023]
Abstract
Unconventional myosins are a superfamily of actin-based molecular motors playing diverse roles including cellular trafficking, mechanical supports, force sensing and transmission, etc. The variable neck and tail domains of unconventional myosins function to bind to specific cargoes including proteins and lipid vesicles and thus are largely responsible for the diverse cellular functions of myosins in vivo. In addition, the tail regions, together with their cognate cargoes, can regulate activities of the motor heads. This review outlines the advances made in recent years on cargo recognition and cargo binding-induced regulation of the activity of several unconventional myosins including myosin-I, V, VI and X in cellular trafficking. We approach this topic by describing a series of high-resolution structures of the neck and tail domains of these unconventional myosins either alone or in complex with their specific cargoes, and by discussing potential implications of these structural studies on cellular trafficking of these myosin motors.
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Affiliation(s)
- Jianchao Li
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Qing Lu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.,Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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2
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Urbanek MO, Galka-Marciniak P, Olejniczak M, Krzyzosiak WJ. RNA imaging in living cells - methods and applications. RNA Biol 2015; 11:1083-95. [PMID: 25483044 PMCID: PMC4615301 DOI: 10.4161/rna.35506] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Numerous types of transcripts perform multiple functions in cells, and these functions are mainly facilitated by the interactions of the RNA with various proteins and other RNAs. Insight into the dynamics of RNA biosynthesis, processing and cellular activities is highly desirable because this knowledge will deepen our understanding of cell physiology and help explain the mechanisms of RNA-mediated pathologies. In this review, we discuss the live RNA imaging systems that have been developed to date. We highlight information on the design of these systems, briefly discuss their advantages and limitations and provide examples of their numerous applications in various organisms and cell types. We present a detailed examination of one application of RNA imaging systems: this application aims to explain the role of mutant transcripts in human disease pathogenesis caused by triplet repeat expansions. Thus, this review introduces live RNA imaging systems and provides a glimpse into their various applications.
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Affiliation(s)
- Martyna O Urbanek
- a Department of Molecular Biomedicine; Institute of Bioorganic Chemistry; Polish Academy of Sciences ; Poznan , Poland
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3
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Kodera N, Ando T. The path to visualization of walking myosin V by high-speed atomic force microscopy. Biophys Rev 2014; 6:237-260. [PMID: 25505494 PMCID: PMC4256461 DOI: 10.1007/s12551-014-0141-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 05/07/2014] [Indexed: 01/14/2023] Open
Abstract
The quest for understanding the mechanism of myosin-based motility started with studies on muscle contraction. From numerous studies, the basic frameworks for this mechanism were constructed and brilliant hypotheses were put forward. However, the argument about the most crucial issue of how the actin-myosin interaction generates contractile force and shortening has not been definitive. To increase the "directness of measurement", in vitro motility assays and single-molecule optical techniques were created and used. Consequently, detailed knowledge of the motility of muscle myosin evolved, which resulted in provoking more arguments to a higher level. In parallel with technical progress, advances in cell biology led to the discovery of many classes of myosins. Myosin V was discovered to be a processive motor, unlike myosin II. The processivity reduced experimental difficulties because it allowed continuous tracing of the motor action of single myosin V molecules. Extensive studies of myosin V were expected to resolve arguments and build a consensus but did not necessarily do so. The directness of measurement was further enhanced by the recent advent of high-speed atomic force microscopy capable of directly visualizing biological molecules in action at high spatiotemporal resolution. This microscopy clearly visualized myosin V molecules walking on actin filaments and at last provided irrefutable evidence for the swinging lever-arm motion propelling the molecules. However, a peculiar foot stomp behavior also appeared in the AFM movie, raising new questions of the chemo-mechanical coupling in this motor and myosin motors in general. This article reviews these changes in the research of myosin motility and proposes new ideas to resolve the newly raised questions.
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Affiliation(s)
- Noriyuki Kodera
- Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa, 920-1192 Japan
- PREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, 332-0012 Japan
| | - Toshio Ando
- Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa, 920-1192 Japan
- Department of Physics, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192 Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, 332-0012 Japan
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4
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Heym RG, Zimmermann D, Edelmann FT, Israel L, Ökten Z, Kovar DR, Niessing D. In vitro reconstitution of an mRNA-transport complex reveals mechanisms of assembly and motor activation. ACTA ACUST UNITED AC 2014; 203:971-84. [PMID: 24368805 PMCID: PMC3871432 DOI: 10.1083/jcb.201302095] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The budding yeast SHE mRNA-transport complex dimerizes to activate processive RNA transport, irrespective of the presence of RNA cargo, and multimerizes upon binding RNAs with multiple localization elements. The assembly and composition of ribonucleic acid (RNA)–transporting particles for asymmetric messenger RNA (mRNA) localization is not well understood. During mitosis of budding yeast, the Swi5p-dependent HO expression (SHE) complex transports a set of mRNAs into the daughter cell. We recombinantly reconstituted the core SHE complex and assessed its properties. The cytoplasmic precomplex contains only one motor and is unable to support continuous transport. However, a defined interaction with a second, RNA-bound precomplex after its nuclear export dimerizes the motor and activates processive RNA transport. The run length observed in vitro is compatible with long-distance transport in vivo. Surprisingly, SHE complexes that either contain or lack RNA cargo show similar motility properties, demonstrating that the RNA-binding protein and not its cargo activates motility. We further show that SHE complexes have a defined size but multimerize into variable particles upon binding of RNAs with multiple localization elements. Based on these findings, we provide an estimate of number, size, and composition of such multimeric SHE particles in the cell.
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Affiliation(s)
- Roland G Heym
- Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, 85764 Neuherberg, Germany
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5
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Abstract
Myosin 4 protein (Myo4p), one of five distinct myosins of yeast, is dedicated to cytoplasmic transport of two types of cargos, zipcoded messenger ribonucleoprotein particles (mRNPs) and tubular endoplasmic reticulum (tER). Neither cargo binds directly to Myo4p. Instead, swi5p-dependent HO expression 3 protein (She3p) serves as an "adaptor" that contains three binding modules, one for Myo4p and one each for zipcoded mRNP and tER. The assembly of a transport-competent motor complex is poorly understood. Here, we report that Myo4p•She3p forms a stable 1:2 heterotrimer in solution. In the Myo4p•She3p crystal structure, Myo4p's C-terminal domain (CTD) assumes a lobster claw-shaped form, the minor prong of which adheres to a pseudocoiled-coil region of She3p. The extensive Myo4p•She3p interactome buries 3,812 Å(2) surface area and is primarily hydrophobic. Because the Myo4p•She3p heterotrimer contains only one myosin molecule, it is not transport-competent. By stepwise reconstitution, we found a single molecule of synthetic oligonucleotide (representing the mRNA zipcode element) bound to a single tetramer of zipcode binding protein She2p to be sufficient for Myo4p•She3p dimerization. Therefore, cargo initiates cross-linking of two Myo4p•She3p heterotrimers to an ensemble that contains two myosin molecules obligatory for movement. An additional crystal structure comprising an overlapping upstream portion of She3p showed continuation of the pseudocoiled-coil structure and revealed another highly conserved surface region. We suggest this region as a candidate binding site for a yet unidentified tER ligand. We propose a model whereby zipcoded mRNP and/or tER ligands couple two Myo4p•She3p heterotrimers and thereby generate a transport-competent motor complex either for separate transport or cotransport of these two cargos.
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Single-molecule reconstitution of mRNA transport by a class V myosin. Nat Struct Mol Biol 2013; 20:952-7. [PMID: 23812374 PMCID: PMC3735863 DOI: 10.1038/nsmb.2614] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/14/2013] [Indexed: 12/27/2022]
Abstract
Molecular motors are instrumental in mRNA localization, which provides spatial and temporal control of protein expression and function. To obtain mechanistic insight into how a class V myosin transports mRNA, we performed single-molecule in vitro assays on messenger ribonucleoprotein (mRNP) complexes reconstituted from purified proteins and a localizing mRNA found in budding yeast. mRNA is required to form a stable, processive transport complex on actin--an elegant mechanism to ensure that only cargo-bound motors are motile. Increasing the number of localizing elements ('zip codes') on the mRNA, or configuring the track to resemble actin cables, enhanced run length and event frequency. In multi-zip-code mRNPs, motor separation distance varied during a run, thus showing the dynamic nature of the transport complex. Building the complexity of single-molecule in vitro assays is necessary to understand how these complexes function within cells.
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7
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Inducible control of subcellular RNA localization using a synthetic protein-RNA aptamer interaction. PLoS One 2012; 7:e46868. [PMID: 23056498 PMCID: PMC3466194 DOI: 10.1371/journal.pone.0046868] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 09/05/2012] [Indexed: 12/18/2022] Open
Abstract
Evidence is accumulating in support of the functional importance of subcellular RNA localization in diverse biological contexts. In different cell types, distinct RNA localization patterns are frequently observed, and the available data indicate that this is achieved through a series of highly coordinated events. Classically, cis–elements within the RNA to be localized are recognized by RNA-binding proteins (RBPs), which then direct specific localization of a target RNA. Until now, the precise control of the spatiotemporal parameters inherent to regulating RNA localization has not been experimentally possible. Here, we demonstrate the development and use of a chemically–inducible RNA–protein interaction to regulate subcellular RNA localization. Our system is composed primarily of two parts: (i) the Tet Repressor protein (TetR) genetically fused to proteins natively involved in localizing endogenous transcripts; and (ii) a target transcript containing genetically encoded TetR–binding RNA aptamers. TetR–fusion protein binding to the target RNA and subsequent localization of the latter are directly regulated by doxycycline. Using this platform, we demonstrate that enhanced and controlled subcellular localization of engineered transcripts are achievable. We also analyze rules for forward engineering this RNA localization system in an effort to facilitate its straightforward application to studying RNA localization more generally.
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Krementsova EB, Hodges AR, Bookwalter CS, Sladewski TE, Travaglia M, Sweeney HL, Trybus KM. Two single-headed myosin V motors bound to a tetrameric adapter protein form a processive complex. ACTA ACUST UNITED AC 2012; 195:631-41. [PMID: 22084309 PMCID: PMC3257522 DOI: 10.1083/jcb.201106146] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myo4p, one of two class V myosins in budding yeast, continuously transports messenger RNA (mRNA) cargo in the cell but is nonprocessive when characterized in vitro. The adapter protein She3p tightly binds to the Myo4p rod, forming a single-headed motor complex. In this paper, we show that two Myo4p-She3p motors are recruited by the tetrameric mRNA-binding protein She2p to form a processive double-headed complex. The binding site for She3p was mapped to a single α helix that protrudes at right angles from She2p. Processive runs of several micrometers on yeast actin-tropomyosin filaments were observed only in the presence of She2p, and, thus, motor activity is regulated by cargo binding. While moving processively, each head steps ~72 nm in a hand-over-hand motion. Coupling two high-duty cycle monomeric motors via a common cargo-binding adapter protein creates a complex with transport properties comparable with a single dimeric processive motor such as vertebrate myosin Va.
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Affiliation(s)
- Elena B Krementsova
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405, USA
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9
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An intracellular transmission control protocol: assembly and transport of ribonucleoprotein complexes. Curr Opin Cell Biol 2012; 24:202-10. [PMID: 22278045 DOI: 10.1016/j.ceb.2011.12.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 12/21/2011] [Accepted: 12/27/2011] [Indexed: 12/31/2022]
Abstract
Initially assumed to be a special feature of highly polarized eukaryotic cells, recent evidence suggests that mRNA localization coupled with local translation is a widespread strategy for spatial restriction of protein synthesis within cells. Genome-wide analyses and live imaging approaches have shed new light on the prevalence and the mechanistic details of this phenomenon. Here we review some of the recent findings that have emerged from research from the RNA localization field, from the birth of mRNAs in the nucleus, to their delivery at specific sites within the cytoplasm.
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Heym RG, Niessing D. Principles of mRNA transport in yeast. Cell Mol Life Sci 2011; 69:1843-53. [PMID: 22159587 PMCID: PMC3350770 DOI: 10.1007/s00018-011-0902-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 11/20/2011] [Accepted: 11/28/2011] [Indexed: 12/20/2022]
Abstract
mRNA localization and localized translation is a common mechanism by which cellular asymmetry is achieved. In higher eukaryotes the mRNA transport machinery is required for such diverse processes as stem cell division and neuronal plasticity. Because mRNA localization in metazoans is highly complex, studies at the molecular level have proven to be cumbersome. However, active mRNA transport has also been reported in fungi including Saccharomyces cerevisiae, Ustilago maydis and Candida albicans, in which these events are less difficult to study. Amongst them, budding yeast S. cerevisiae has yielded mechanistic insights that exceed our understanding of other mRNA localization events to date. In contrast to most reviews, we refrain here from summarizing mRNA localization events from different organisms. Instead we give an in-depth account of ASH1 mRNA localization in budding yeast. This approach is particularly suited to providing a more holistic view of the interconnection between the individual steps of mRNA localization, from transcriptional events to cytoplasmic mRNA transport and localized translation. Because of our advanced mechanistic understanding of mRNA localization in yeast, the present review may also be informative for scientists working, for example, on mRNA localization in embryogenesis or in neurons.
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Affiliation(s)
- Roland Gerhard Heym
- Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, 81377 Munich, Germany
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Dierk Niessing
- Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, 81377 Munich, Germany
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
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11
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Gagnon JA, Mowry KL. Molecular motors: directing traffic during RNA localization. Crit Rev Biochem Mol Biol 2011; 46:229-39. [PMID: 21476929 DOI: 10.3109/10409238.2011.572861] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RNA localization, the enrichment of RNA in a specific subcellular region, is a mechanism for the establishment and maintenance of cellular polarity in a variety of systems. Ultimately, this results in a universal method for spatially restricting gene expression. Although the consequences of RNA localization are well-appreciated, many of the mechanisms that are responsible for carrying out polarized transport remain elusive. Several recent studies have illuminated the roles that molecular motor proteins play in the process of RNA localization. These studies have revealed complex mechanisms in which the coordinated action of one or more motor proteins can act at different points in the localization process to direct RNAs to their final destination. In this review, we discuss recent findings from several different systems in an effort to clarify pathways and mechanisms that control the directed movement of RNA.
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Affiliation(s)
- James A Gagnon
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI, USA
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12
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Sun X, Kovacs T, Hu YJ, Yang WX. The role of actin and myosin during spermatogenesis. Mol Biol Rep 2010; 38:3993-4001. [DOI: 10.1007/s11033-010-0517-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2010] [Accepted: 11/13/2010] [Indexed: 01/08/2023]
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13
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Heuck A, Fetka I, Brewer DN, Hüls D, Munson M, Jansen RP, Niessing D. The structure of the Myo4p globular tail and its function in ASH1 mRNA localization. ACTA ACUST UNITED AC 2010; 189:497-510. [PMID: 20439999 PMCID: PMC2867299 DOI: 10.1083/jcb.201002076] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A conserved patch of amino acids in the globular tail of type V myosin binds She3p to localize ASH1 mRNA to the bud of dividing yeast cells. Type V myosin (MyoV)–dependent transport of cargo is an essential process in eukaryotes. Studies on yeast and vertebrate MyoV showed that their globular tails mediate binding to the cargo complexes. In Saccharomyces cerevisiae, the MyoV motor Myo4p interacts with She3p to localize asymmetric synthesis of HO 1 (ASH1) mRNA into the bud of dividing cells. A recent study showed that localization of GFP-MS2–tethered ASH1 particles does not require the Myo4p globular tail, challenging the supposed role of this domain. We assessed ASH1 mRNA and Myo4p distribution more directly and found that their localization is impaired in cells expressing globular tail–lacking Myo4p. In vitro studies further show that the globular tail together with a more N-terminal linker region is required for efficient She3p binding. We also determined the x-ray structure of the Myo4p globular tail and identify a conserved surface patch important for She3p binding. The structure shows pronounced similarities to membrane-tethering complexes and indicates that Myo4p may not undergo auto-inhibition of its motor domain.
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Affiliation(s)
- Alexander Heuck
- Institute of Structural Biology, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany
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14
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Chung S, Takizawa PA. Multiple Myo4 motors enhance ASH1 mRNA transport in Saccharomyces cerevisiae. ACTA ACUST UNITED AC 2010; 189:755-67. [PMID: 20457760 PMCID: PMC2872910 DOI: 10.1083/jcb.200912011] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In Saccharomyces cerevisiae, ASH1 mRNA is transported to the bud tip by the class V myosin Myo4. In vivo, Myo4 moves RNA in a rapid and continuous fashion, but in vitro Myo4 is a nonprocessive, monomeric motor that forms a complex with She3. To understand how nonprocessive motors generate continuous transport, we used a novel purification method to show that Myo4, She3, and the RNA-binding protein She2 are the sole major components of an active ribonucleoprotein transport unit. We demonstrate that a single localization element contains multiple copies of Myo4 and a tetramer of She2, which suggests that She2 may recruit multiple motors to an RNA. Furthermore, we show that increasing the number of Myo4-She3 molecules bound to ASH1 RNA in the absence of She2 increases the efficiency of RNA transport to the bud. Our data suggest that multiple, nonprocessive Myo4 motors can generate continuous transport of mRNA to the bud tip.
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Affiliation(s)
- Sunglan Chung
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
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15
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Meignin C, Davis I. Transmitting the message: intracellular mRNA localization. Curr Opin Cell Biol 2010; 22:112-9. [DOI: 10.1016/j.ceb.2009.11.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 11/16/2009] [Accepted: 11/20/2009] [Indexed: 11/25/2022]
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Current awareness on yeast. Yeast 2010. [DOI: 10.1002/yea.1713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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