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Mechanisms of Regulation in Intraflagellar Transport. Cells 2022; 11:cells11172737. [PMID: 36078145 PMCID: PMC9454703 DOI: 10.3390/cells11172737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Cilia are eukaryotic organelles essential for movement, signaling or sensing. Primary cilia act as antennae to sense a cell’s environment and are involved in a wide range of signaling pathways essential for development. Motile cilia drive cell locomotion or liquid flow around the cell. Proper functioning of both types of cilia requires a highly orchestrated bi-directional transport system, intraflagellar transport (IFT), which is driven by motor proteins, kinesin-2 and IFT dynein. In this review, we explore how IFT is regulated in cilia, focusing from three different perspectives on the issue. First, we reflect on how the motor track, the microtubule-based axoneme, affects IFT. Second, we focus on the motor proteins, considering the role motor action, cooperation and motor-train interaction plays in the regulation of IFT. Third, we discuss the role of kinases in the regulation of the motor proteins. Our goal is to provide mechanistic insights in IFT regulation in cilia and to suggest directions of future research.
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2
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Li S, Wan KY, Chen W, Tao H, Liang X, Pan J. Functional exploration of heterotrimeric kinesin-II in IFT and ciliary length control in Chlamydomonas. eLife 2020; 9:58868. [PMID: 33112235 PMCID: PMC7652414 DOI: 10.7554/elife.58868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 10/28/2020] [Indexed: 12/27/2022] Open
Abstract
Heterodimeric motor organization of kinesin-II is essential for its function in anterograde IFT in ciliogenesis. However, the underlying mechanism is not well understood. In addition, the anterograde IFT velocity varies significantly in different organisms, but how this velocity affects ciliary length is not clear. We show that in Chlamydomonas motors are only stable as heterodimers in vivo, which is likely the key factor for the requirement of a heterodimer for IFT. Second, chimeric CrKinesin-II with human kinesin-II motor domains functioned in vitro and in vivo, leading to a ~ 2.8 fold reduced anterograde IFT velocity and a similar fold reduction in IFT injection rate that supposedly correlates with ciliary assembly activity. However, the ciliary length was only mildly reduced (~15%). Modeling analysis suggests a nonlinear scaling relationship between IFT velocity and ciliary length that can be accounted for by limitation of the motors and/or its ciliary cargoes, e.g. tubulin.
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Affiliation(s)
- Shufen Li
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Kirsty Y Wan
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Wei Chen
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Hui Tao
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xin Liang
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Junmin Pan
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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Douglas RL, Haltiwanger BM, Albisetti A, Wu H, Jeng RL, Mancuso J, Cande WZ, Welch MD. Trypanosomes have divergent kinesin-2 proteins that function differentially in flagellum biosynthesis and cell viability. J Cell Sci 2020; 133:jcs129213. [PMID: 32503938 DOI: 10.1242/jcs.129213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/27/2020] [Indexed: 12/13/2022] Open
Abstract
Trypanosoma brucei, the causative agent of African sleeping sickness, has a flagellum that is crucial for motility, pathogenicity, and viability. In most eukaryotes, the intraflagellar transport (IFT) machinery drives flagellum biogenesis, and anterograde IFT requires kinesin-2 motor proteins. In this study, we investigated the function of the two T. brucei kinesin-2 proteins, TbKin2a and TbKin2b, in bloodstream form trypanosomes. We found that, compared to kinesin-2 proteins across other phyla, TbKin2a and TbKin2b show greater variation in neck, stalk and tail domain sequences. Both kinesins contributed additively to flagellar lengthening. Silencing TbKin2a inhibited cell proliferation, cytokinesis and motility, whereas silencing TbKin2b did not. TbKin2a was localized on the flagellum and colocalized with IFT components near the basal body, consistent with it performing a role in IFT. TbKin2a was also detected on the flagellar attachment zone, a specialized structure that connects the flagellum to the cell body. Our results indicate that kinesin-2 proteins in trypanosomes play conserved roles in flagellar biosynthesis and exhibit a specialized localization, emphasizing the evolutionary flexibility of motor protein function in an organism with a large complement of kinesins.
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Affiliation(s)
- Robert L Douglas
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Brett M Haltiwanger
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Anna Albisetti
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Haiming Wu
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Robert L Jeng
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Joel Mancuso
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - W Zacheus Cande
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Matthew D Welch
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
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Ahmed Z, Mazumdar S, Ray K. Kinesin associated protein, DmKAP, binding harnesses the C-terminal ends of the Drosophila kinesin-2 stalk heterodimer. Biochem Biophys Res Commun 2019; 522:506-511. [PMID: 31784087 DOI: 10.1016/j.bbrc.2019.11.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 11/17/2019] [Indexed: 01/01/2023]
Abstract
The heterotrimeric kinesin-2 consists of two distinct motor subunits and an accessory protein, KAP, which binds to the coiled-coil stalk domains and one of the tail domains of the motor subunits. Genetic studies revealed that KAP is essential for the kinesin-2 functions in cilia, flagella, and axon. However, the structural significance of the KAP binding on kinesin-2 assembly and stability is not known. Here, using the Fluorescence Lifetime assay, we show that DmKAP binding selectively reduces the distance between the C-terminal ends of Drosophila kinesin-2 stalk heterodimer. Insertion of a missense mutation (E551K) in the Drosophila kinesin-2α stalk fragment, which was shown to reduce the structural dynamics of the stalk heterodimer earlier, also reduced the distances at both the N- and C-terminal ends of the stalk heterodimer independent of DmKAP. The zipping effect, particularly at the N-terminal end of the mutant stalk heterodimer, is further enhanced in the presence of DmKAP. Together, these results suggest that the KAP binding could alter the structural dynamics of kinesin-2 stalk heterodimer at the C-terminal end and stabilize the association between the stalk domains.
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Affiliation(s)
- Zoheb Ahmed
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, 400005, India
| | - Shyamalava Mazumdar
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, 400005, India
| | - Krishanu Ray
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, 400005, India.
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Ahmed Z, Doodhi H, Bhaumik A, Mazumdar S, Ray K. The structural dynamics of the kinesin-2 stalk heterodimer and its biological relevance. Biochem Biophys Res Commun 2019; 518:171-177. [DOI: 10.1016/j.bbrc.2019.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 08/06/2019] [Indexed: 11/25/2022]
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Abstract
Production of soluble protein remains a bottleneck in the biochemistry and structural biology fields. Unfortunately, there is no 'magic bullet' that solves all solubility problems. The following is a protocol to test whether a protein expressed recombinantly is soluble, and possible strategies to circumvent insolubility issues.
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Cho NJ, Lee C, Pang PS, Pham EA, Fram B, Nguyen K, Xiong A, Sklan EH, Elazar M, Koytak ES, Kersten C, Kanazawa KK, Frank CW, Glenn JS. Phosphatidylinositol 4,5-bisphosphate is an HCV NS5A ligand and mediates replication of the viral genome. Gastroenterology 2015; 148:616-25. [PMID: 25479136 PMCID: PMC4339471 DOI: 10.1053/j.gastro.2014.11.043] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 11/21/2014] [Accepted: 11/23/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND & AIMS Phosphoinositides (PIs) bind and regulate localization of proteins via a variety of structural motifs. PI 4,5-bisphosphate (PI[4,5]P2) interacts with and modulates the function of several proteins involved in intracellular vesicular membrane trafficking. We investigated interactions between PI(4,5)P2 and hepatitis C virus (HCV) nonstructural protein 5A (NS5A) and effects on the viral life cycle. METHODS We used a combination of quartz crystal microbalance, circular dichroism, molecular genetics, and immunofluorescence to study specific binding of PI(4,5)P2 by the HCV NS5A protein. We evaluated the effects of PI(4,5)P2 on the function of NS5A by expressing wild-type or mutant forms of Bart79I or FL-J6/JFH-5'C19Rluc2AUbi21 RNA in Huh7 cells. We also studied the effects of strategies designed to inhibit PI(4,5)P2 on HCV replication in these cells. RESULTS The N-terminal amphipathic helix of NS5A bound specifically to PI(4,5)P2, inducing a conformational change that stabilized the interaction between NS5A and TBC1D20, which is required for HCV replication. A pair of positively charged residues within the amphipathic helix (the basic amino acid PI(4,5)P2 pincer domain) was required for PI(4,5)P2 binding and replication of the HCV-RNA genome. A similar motif was found to be conserved across all HCV isolates, as well as amphipathic helices of many pathogens and apolipoproteins. CONCLUSIONS PI(4,5)P2 binds to HCV NS5A to promote replication of the viral RNA genome in hepatocytes. Strategies to disrupt this interaction might be developed to inhibit replication of HCV and other viruses.
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Affiliation(s)
- Nam-Joon Cho
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Choongho Lee
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Phillip S Pang
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California
| | - Edward A Pham
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California
| | - Benjamin Fram
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Khanh Nguyen
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Anming Xiong
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Ella H Sklan
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Menashe Elazar
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Elif S Koytak
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Caroline Kersten
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Kay K Kanazawa
- Department of Chemical Engineering, Stanford University, Stanford, California
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford, California
| | - Jeffrey S Glenn
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California; Veterans Administration Medical Center, Palo Alto, California.
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Scholey JM. Kinesin-2: a family of heterotrimeric and homodimeric motors with diverse intracellular transport functions. Annu Rev Cell Dev Biol 2013; 29:443-69. [PMID: 23750925 DOI: 10.1146/annurev-cellbio-101512-122335] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Kinesin-2 was first purified as a heterotrimeric, anterograde, microtubule-based motor consisting of two distinct kinesin-related subunits and a novel associated protein (KAP) that is currently best known for its role in intraflagellar transport and ciliogenesis. Subsequent work, however, has revealed diversity in the oligomeric state of different kinesin-2 motors owing to the combinatorial heterodimerization of its subunits and the coexistence of both heterotrimeric and homodimeric kinesin-2 motors in some cells. Although the functional significance of the homo- versus heteromeric organization of kinesin-2 motor subunits and the role of KAP remain uncertain, functional studies suggest that cooperation between different types of kinesin-2 motors or between kinesin-2 and a member of a different motor family can generate diverse patterns of anterograde intracellular transport. Moreover, despite being restricted to ciliated eukaryotes, kinesin-2 motors are now known to drive diverse transport events outside cilia. Here, I review the organization, assembly, phylogeny, biological functions, and motility mechanism of this diverse family of intracellular transport motors.
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Affiliation(s)
- Jonathan M Scholey
- Department of Molecular and Cell Biology, University of California, Davis, California 95616;
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Doodhi H, Jana SC, Devan P, Mazumdar S, Ray K. Biochemical and molecular dynamic simulation analysis of a weak coiled coil association between kinesin-II stalks. PLoS One 2012; 7:e45981. [PMID: 23029351 PMCID: PMC3461054 DOI: 10.1371/journal.pone.0045981] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 08/27/2012] [Indexed: 01/03/2023] Open
Abstract
DEFINITION Kinesin-2 refers to the family of motor proteins represented by conserved, heterotrimeric kinesin-II and homodimeric Osm3/Kif17 class of motors. BACKGROUND Kinesin-II, a microtubule-based anterograde motor, is composed of three different conserved subunits, named KLP64D, KLP68D and DmKAP in Drosophila. Although previous reports indicated that coiled coil interaction between the middle segments of two dissimilar motor subunits established the heterodimer, the molecular basis of the association is still unknown. METHODOLOGY/PRINCIPAL FINDINGS Here, we present a detailed heterodimeric association model of the KLP64D/68D stalk supported by extensive experimental analysis and molecular dynamic simulations. We find that KLP64D stalk is unstable, but forms a weak coiled coil heteroduplex with the KLP68D stalk when coexpressed in bacteria. Local instabilities, relative affinities between the C-terminal stalk segments, and dynamic long-range interactions along the stalks specify the heterodimerization. Thermal unfolding studies and independent simulations further suggest that interactions between the C-terminal stalk fragments are comparatively stable, whereas the N-terminal stalk reversibly unfolds at ambient temperature. CONCLUSIONS/SIGNIFICANCE Results obtained in this study suggest that coiled coil interaction between the C-terminal stalks of kinesin-II motor subunits is held together through a few hydrophobic and charged interactions. The N-terminal stalk segments are flexible and could uncoil reversibly during a motor walk. This supports the requirement for a flexible coiled coil association between the motor subunits, and its role in motor function needs to be elucidated.
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Affiliation(s)
- Harinath Doodhi
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Swadhin C. Jana
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Pavithra Devan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Shyamalava Mazumdar
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Krishanu Ray
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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Huang CF, Banker G. The translocation selectivity of the kinesins that mediate neuronal organelle transport. Traffic 2012; 13:549-64. [PMID: 22212743 DOI: 10.1111/j.1600-0854.2011.01325.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 12/22/2011] [Accepted: 12/28/2011] [Indexed: 12/22/2022]
Abstract
Polarized kinesin-driven transport is crucial for development and maintenance of neuronal polarity. Kinesins are thought to recognize biochemical differences between axonal and dendritic microtubules in order to deliver their cargoes to the appropriate domain. To identify kinesins that mediate polarized transport, we prepared constitutively active versions of all the kinesins implicated in vesicle transport and expressed them in cultured hippocampal neurons. Seven kinesins translocated preferentially to axons and five translocated into both axons and dendrites. None translocated selectively to dendrites. Highly homologous members of the same subfamily displayed distinctly different translocation preferences and were differentially regulated during development. By expressing chimeric kinesins, we identified two microtubule-binding elements within the motor domain that are important for selective translocation. We also discovered elements in the dimerization domain of kinesin-2 motors that contribute to their selective translocation. These observations indicate that selective interactions between kinesin motor domains and microtubules can account for polarized transport to the axon, but not for selective dendritic transport.
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Affiliation(s)
- Chun-Fang Huang
- The Jungers Center for Neurosciences Research, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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11
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Abstract
The two distinct motor domains KLP11 and KLP20 of Caenorhabditis elegans kinesin-2 require a dimerization seed of two heptads at the C terminus of the stalk to promote heterodimerization along the entire length of the stalk. This short sequence bears great potential for generating specific heterodimerization in other protein biochemical applications. The heterotrimeric structure of kinesin-2 makes it a unique member of the kinesin superfamily; however, molecular details of the oligomer formation are largely unknown. Here we demonstrate that heterodimerization of the two distinct motor domains KLP11 and KLP20 of Caenorhabditis elegans kinesin-2 requires a dimerization seed of merely two heptads at the C terminus of the stalk. This heterodimeric seed is sufficient to promote dimerization along the entire length of the stalk, as shown by circular dichroism spectroscopy, Förster resonance energy transfer analysis, and electron microscopy. In addition to explaining the formation of the kinesin-2 stalk, the seed sequence identified here bears great potential for generating specific heterodimerization in other protein biochemical applications.
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Affiliation(s)
- Marija Vukajlovic
- Center for Integrated Protein Science Munich and Institute for Cell Biology, Ludwig-Maximilians-Universität, D-80336 Munich, Germany
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12
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Abstract
Long-distance transport in eukaryotic cells is driven by molecular motors that move along microtubule tracks. Molecular motors of the kinesin superfamily contain a kinesin motor domain attached to family-specific sequences for cargo binding, regulation, and oligomerization. The biochemical and biophysical properties of the kinesin motor domain have been widely studied, yet little is known about how kinesin motors work in the complex cellular environment. We discuss recent studies on the three major families involved in intracellular transport (kinesin-1, kinesin-2, and kinesin-3) that have begun to bridge the gap in knowledge between the in vitro and in vivo behaviors of kinesin motors. These studies have increased our understanding of how kinesin subunits assemble to produce a functional motor, how kinesin motors are affected by biochemical cues and obstacles present on cellular microtubules, and how multiple motors on a cargo surface can work collectively for increased force production and travel distance.
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Affiliation(s)
- Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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Jana SC, Girotra M, Ray K. Heterotrimeric kinesin-II is necessary and sufficient to promote different stepwise assembly of morphologically distinct bipartite cilia in Drosophila antenna. Mol Biol Cell 2011; 22:769-81. [PMID: 21233284 PMCID: PMC3057702 DOI: 10.1091/mbc.e10-08-0712] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Structurally diverse sensory cilia have evolved from primary cilia, a microtubule-based cellular extension engaged in chemical and mechanical sensing and signal integration. The diversity is often associated with functional specialization. The olfactory receptor neurons in Drosophila, for example, express three distinct bipartite cilia displaying different sets of olfactory receptors on them. Molecular description underlying their assembly and diversification is still incomplete. Here, we show that the branched and the slender olfactory cilia develop in two distinct step-wise patterns through the pupal stages before the expression of olfactory receptor genes in olfactory neurons. The process initiates with a thin procilium growth from the dendrite apex, followed by volume increment in successive stages. Mutations in the kinesin-II subunit genes either eliminate or restrict the cilia growth as well as tubulin entry into the developing cilia. Together with previous results, our results here suggest that heterotrimeric kinesin-II is the primary motor engaged in all type-I sensory cilia assembly in Drosophila and that the cilia structure diversity is achieved through additional transports supported by the motor during development.
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Affiliation(s)
- Swadhin C Jana
- Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
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14
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Abstract
This chapter describes the use of analytical ultracentrifugation in a Beckman XLA to study the self-association properties of tubulin and the interaction of tubulin with antimitotic drugs. Procedures for sample preparation, operation of the ultracentrifuge, and collection of data conform to standard modern methods. Analysis of sedimentation velocity data initially includes generation of g(s) sedimentation coefficient distributions with DCDT(+2) and determination of weight average sedimentation coefficients S(w). S(w) versus concentration data are then fit to isodesmic or indefinite assembly models to extract K(iso) values, the association constant for each successive assembly step. Alternatively the raw data can also be analyzed by direct boundary analysis methods using the program Sedanal. Direct boundary analysis also extracts the K(iso) value by fitting to the shape of the sedimentation boundary as a function of total concentration. While the fitting of weight average data as a function of protein or drug concentration to indefinite assembly models has been shown to be equivalent to direct boundary fitting of multiple data sets with Sedanal, direct boundary fitting is preferred because it robustly identifies the presence of irreversible aggregation or mechanisms that are more complex.
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Cho NJ, Dvory-Sobol H, Xiong A, Cho SJ, Frank CW, Glenn JS. Mechanism of an amphipathic alpha-helical peptide's antiviral activity involves size-dependent virus particle lysis. ACS Chem Biol 2009; 4:1061-7. [PMID: 19928982 DOI: 10.1021/cb900149b] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The N-terminal region of the hepatitis C virus (HCV) nonstructural protein NS5A contains an amphipathic alpha-helix that is necessary and sufficient for NS5A membrane association. A synthetic peptide (AH) comprising this amphipathic helix is able to lyse lipid vesicles that serve as a model system for virus particles. Based on quartz crystal microbalance-dissipation (QCM-D) experiments, the degree of vesicle rupturing was found to be inversely related to vesicle size, with maximal activity in the size range of several medically important viruses. In order to confirm and further study vesicle rupture, dynamic light scattering (DLS) and atomic force microscopy (AFM) experiments were also performed. The size dependence of vesicle rupturing helps explain the peptide's observed effect on the infectivity of a wide range of viruses. Further, in vitro studies demonstrated that AH peptide treatment significantly decreased the infectivity of HCV particles. Thus, the AH peptide might be used to rupture HCV particles extra-corporally (for HCV prevention) and within infected individuals (for HCV therapy).
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Affiliation(s)
- Nam-Joon Cho
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
| | - Hadas Dvory-Sobol
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
| | - Anming Xiong
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
| | | | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
| | - Jeffrey S. Glenn
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
- Palo Alto Veterans Administration
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16
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Doodhi H, Ghosal D, Krishnamurthy M, Jana SC, Shamala D, Bhaduri A, Sowdhamini R, Ray K. KAP, the accessory subunit of kinesin-2, binds the predicted coiled-coil stalk of the motor subunits. Biochemistry 2009; 48:2248-60. [PMID: 19161286 DOI: 10.1021/bi8018338] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinesin-2 is an anterograde motor involved in intraflagellar transport and certain other intracellular transport processes. It consists of two different motor subunits and an accessory protein KAP (kinesin accessory protein). The motor subunits were shown to bind each other through the coiled-coil stalk domains, while KAP was proposed to bind the tail domains of the motor subunits. Although several genetic studies established that KAP plays an important role in kinesin-2 functions, its exact role remains unclear. Here, we report the results of a systematic analysis of the KAP binding sites by using recombinant Drosophila kinesin-2 subunits as well as the endogenous proteins. These show that at least one of the coiled-coil stalks is sufficient to bind the N-terminal region of DmKAP. The soluble complex involving the recombinant kinesin-2 fragments is reconstituted in vitro at high salt concentrations, suggesting that the interaction is primarily nonionic. Furthermore, independent distant homology modeling indicated that DmKAP may bind along the coiled-coil stalks through a combination of predominantly hydrophobic interactions and hydrogen bonds. These observations led us to propose that KAP would stabilize the motor subunit heterodimer and help assemble a greater kinesin-2 complex in vivo.
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Affiliation(s)
- Harinath Doodhi
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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17
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Protocol for preparing proteins with improved solubility by co-expressing with molecular chaperones in Escherichia coli. Nat Protoc 2007; 2:2632-9. [DOI: 10.1038/nprot.2007.400] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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de Marco A, Deuerling E, Mogk A, Tomoyasu T, Bukau B. Chaperone-based procedure to increase yields of soluble recombinant proteins produced in E. coli. BMC Biotechnol 2007; 7:32. [PMID: 17565681 PMCID: PMC1904446 DOI: 10.1186/1472-6750-7-32] [Citation(s) in RCA: 209] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 06/12/2007] [Indexed: 11/10/2022] Open
Abstract
Background The overproduction of recombinant proteins in host cells often leads to their misfolding and aggregation. Previous attempts to increase the solubility of recombinant proteins by co-overproduction of individual chaperones were only partially successful. We now assessed the effects of combined overproduction of the functionally cooperating chaperone network of the E. coli cytosol on the solubility of recombinant proteins. Results A two-step procedure was found to show the strongest enhancement of solubility. In a first step, the four chaperone systems GroEL/GroES, DnaK/DnaJ/GrpE, ClpB and the small HSPs IbpA/IbpB, were coordinately co-overproduced with recombinant proteins to optimize de novo folding. In a second step, protein biosynthesis was inhibited to permit chaperone mediated refolding of misfolded and aggregated proteins in vivo. This novel strategy increased the solubility of 70% of 64 different heterologous proteins tested up to 42-fold. Conclusion The engineered E. coli strains and the two-step procedure presented here led to a remarkable increase in the solubility of a various recombinant proteins and should be applicable to a wide range of target proteins produced in biotechnology.
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Affiliation(s)
- Ario de Marco
- EMBL Heidelberg, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- IFOM-IEO Campus for Oncogenomics, via Adamello 16, I-20139, Milano, Italy
| | - Elke Deuerling
- ZMBH, Universität Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Axel Mogk
- ZMBH, Universität Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Toshifumi Tomoyasu
- Department of Microbiology and Molecular Genetics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoicho, Inageku, Chiba 263-8522, Japan
| | - Bernd Bukau
- ZMBH, Universität Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
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Abstract
Recent research on kinesin motors has outlined the diversity of the superfamily and defined specific cargoes moved by kinesin family (KIF) members. Owing to the difficulty of purifying large amounts of native motors, much of this work has relied on recombinant proteins expressed in vitro. This approach does not allow ready determination of the complement of kinesin motors present in a given tissue, the relative amounts of different motors, or comparison of their native activities. To address these questions, we isolated nucleotide-dependent, microtubule-binding proteins from 13-day chick embryo brain. Proteins were enriched by microtubule affinity purification, then subjected to velocity sedimentation to separate the 20S dynein/dynactin pool from a slower sedimenting KIF containing pool. Analysis of the latter pool by anion exchange chromatography revealed three KIF species: kinesin I (KIF5), kinesin II (KIF3), and KIF1C (Unc104/KIF1). The most abundant species, kinesin I, exhibited the expected long range microtubule gliding activity. By contrast, KIF1C did not move microtubules. Kinesin II, the second most abundant KIF, could be fractionated into two pools, one containing predominantly A/B isoforms and the other containing A/C isoforms. The two motor species had similar activities, powering microtubule gliding at slower speeds and over shorter distances than kinesin I.
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Affiliation(s)
- Matthew A Berezuk
- Department of Biology, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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De Marco V, Stier G, Blandin S, de Marco A. The solubility and stability of recombinant proteins are increased by their fusion to NusA. Biochem Biophys Res Commun 2004; 322:766-71. [PMID: 15336530 DOI: 10.1016/j.bbrc.2004.07.189] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Indexed: 11/30/2022]
Abstract
The new bacterial vector pETM60 enables the expression of His-tagged recombinant proteins fused to the C-terminus of NusA through a TEV protease recognition sequence. Three sequences coding for two protein domains (Xklp3A and Tep3Ag) and one membrane-bound viral protein (E8R) could not be expressed in a soluble form in bacteria. Their GST-fusions were mostly soluble but quickly degraded during purification. The same sequences cloned in pETM60 were efficiently purified by metal affinity and recovered soluble after the removal of the fusion partner. The NusA-fused constructs enabled to yield 13-20mg of fusion protein per litre of culture and 2.5-5mg of pure protein per litre of culture. Structural analysis indicated that the purified proteins were monodispersed and correctly folded. NusA has been used to raise antibodies that have been successfully used for Western blot and immunoprecipitation of NusA fusion proteins.
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