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Verdan R, Patricio B, Weismuller G, Miranda K, de Souza W, Benchimol M, Gadelha AP. Characterization of a new extra-axonemal structure in the Giardia intestinalis flagella. J Struct Biol 2024; 216:108064. [PMID: 38280689 DOI: 10.1016/j.jsb.2024.108064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/05/2024] [Accepted: 01/18/2024] [Indexed: 01/29/2024]
Abstract
The inner structure of the flagella of Giardia intestinalis is similar to that of other organisms, consisting of nine pairs of outer microtubules and a central pair containing radial spokes. Although the 9+2 axonemal structure is conserved, it is not clear whether subregions, including the transition zone, are present in the flagella of this parasite. Giardia axonemes originate from basal bodies and have a lengthy cytosolic portion before becoming active flagella. The region of the emergence of the flagellum is not accompanied by any membrane specialization, as seen in other protozoa. Although Giardia is an intriguing model of study, few works focused on the ultrastructural analysis of the flagella of this parasite. Here, we analyzed the externalization region of the G. intestinalis flagella using ultra-high resolution scanning microscopy (with electrons and ions), atomic force microscopy in liquid medium, freeze fracture, and electron tomography. Our data show that this region possesses a distinctive morphological feature - it extends outward and takes on a ring-like shape. When the plasma membrane is removed, a structure surrounding the axoneme becomes visible in this region. This new extra-axonemal structure is observed in all pairs of flagella of trophozoites and remains attached to the axoneme even when the interconnections between the axonemal microtubules are disrupted. High-resolution scanning electron microscopy provided insights into the arrangement of this structure, contributing to the characterization of the externalization region of the flagella of this parasite.
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Affiliation(s)
- Raphael Verdan
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Beatriz Patricio
- Instituto Biomédico, Universidade Federal do Estado Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gilberto Weismuller
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kildare Miranda
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem e Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Multiusuário para Análise de Fenômenos Biomédicos, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem e Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Multiusuário para Análise de Fenômenos Biomédicos, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Marlene Benchimol
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem e Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Universidade do Grande Rio (UNIGRANRIO), Rio de Janeiro, RJ, Brazil
| | - Ana Paula Gadelha
- Universidade do Grande Rio (UNIGRANRIO), Rio de Janeiro, RJ, Brazil; Diretoria de Metrologia Científica e Industrial, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Rio de Janeiro, Rio de Janeiro, Brazil.
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2
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Benchimol M, de Souza W. Giardia intestinalis and its Endomembrane System. J Eukaryot Microbiol 2022; 69:e12893. [PMID: 35148450 DOI: 10.1111/jeu.12893] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/08/2022] [Accepted: 02/08/2022] [Indexed: 11/29/2022]
Abstract
Giardia intestinalis has unique characteristics, even in the absence of certain organelles. For instance, Golgi and mitochondria are not found. On the other hand, there is a network of peripheral vacuoles (PVs) and mitosomes. The endoplasmic reticulum (ER), nuclear membrane, peroxisomes, and lipid bodies are present. The peripheral vacuole system seems to play several simultaneous roles. It is involved in the endocytic activity of the trophozoite but also has characteristics of early and late endosomes and even lysosomes, establishing a connection with the ER. Some of the PVs contain small vesicles, acting as multivesicular bodies, including the release of exosomes. The mitosomes are surrounded by two membranes, divide during mitosis, and are distributed throughout the cell. They do not contain DNA, enzymes involved in the citric acid cycle, respiratory chain, or ATP synthesis. However, they contain the iron-sulfur complex and transporters as TOM and TIM. Some mitosomes are linked to flagellar axonemes through a fibrillar connection. During encystation, two types of larger cytoplasmic vesicles appear. One originating from the ER contains the cyst wall proteins. Another contains carbohydrates. Both migrate to the cell periphery and fuse with plasma membrane secreting their contents to give rise to the cell wall.
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Affiliation(s)
- Marlene Benchimol
- Universidade do Grande Rio (UNIGRANRIO), Rio de Janeiro Duque de Caxias, RJ, Brazil.,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Centro Nacional de Biologia Estrutural e Bioimagens, CENABIO-Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Centro Nacional de Biologia Estrutural e Bioimagens, CENABIO-Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Lagunas-Rangel FA, Yee J, Bermúdez-Cruz RM. An update on cell division of Giardia duodenalis trophozoites. Microbiol Res 2021; 250:126807. [PMID: 34130067 DOI: 10.1016/j.micres.2021.126807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/08/2021] [Accepted: 06/08/2021] [Indexed: 11/30/2022]
Abstract
Giardia duodenalis is a flagellated protozoan that is responsible for many cases of diarrheal disease worldwide and is characterized by its great divergence from the model organisms commonly used in studies of basic cellular processes. The life cycle of Giardia involves an infectious cyst form and a proliferative and mobile trophozoite form. Each Giardia trophozoite has two nuclei and a complex microtubule cytoskeleton that consists of eight flagellar axonemes, basal bodies, the adhesive disc, the funis and the median body. Since the success of Giardia infecting other organisms depends on its ability to divide and proliferate efficiently, Giardia must coordinate its cell division to ensure the duplication and partitioning of both nuclei and the multiple cytoskeletal structures. The purpose of this review is to summarize current knowledge about cell division and its regulation in this protist.
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Affiliation(s)
- Francisco Alejandro Lagunas-Rangel
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico; Department of Neuroscience, Functional Pharmacology, Uppsala University, Uppsala, Sweden
| | - Janet Yee
- Department of Biology, Biochemistry and Molecular Biology Program, Trent University, Peterborough, ON, Canada
| | - Rosa María Bermúdez-Cruz
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico.
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4
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Park EA, Kim J, Shin MY, Park SJ. A polo-like kinase modulates cytokinesis and flagella biogenesis in Giardia lamblia. Parasit Vectors 2021; 14:182. [PMID: 33789729 PMCID: PMC8011197 DOI: 10.1186/s13071-021-04687-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/16/2021] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Polo-like kinases (PLKs) are conserved serine/threonine kinases that regulate the cell cycle. To date, the role of Giardia lamblia PLK (GlPLK) in cells has not been studied. Here, we report our investigation on the function of GlPLK to provide insight into the role of this PKL in Giardia cell division, especially during cytokinesis and flagella formation. METHODS To assess the function of GIPLK, Giardia trophozoites were treated with the PLK-specific inhibitor GW843286X (GW). Using a putative open reading frame for the PLK identified in the Giardia genomic database, we generated a transgenic Giardia expressing hemagglutinin (HA)-tagged GlPLK and used this transgenic for immunofluorescence assays (IFAs). GlPLK expression was knocked down using an anti-glplk morpholino to observe its effect on the number of nuclei number and length of flagella. Giardia cells ectopically expressing truncated GlPLKs, kinase domain + linker (GlPLK-KDL) or polo-box domains (GlPLK-PBD) were constructed for IFAs. Mutant GlPLKs at Lys51, Thr179 and Thr183 were generated by site-directed mutagenesis and then used for the kinase assay. To elucidate the role of phosphorylated GlPLK, the phosphorylation residues were mutated and expressed in Giardia trophozoites RESULTS: After incubating trophozoites with 5 μM GW, the percentage of cells with > 4 nuclei and longer caudal and anterior flagella increased. IFAs indicated that GlPLK was localized to basal bodies and flagella and was present at mitotic spindles in dividing cells. Morpholino-mediated GlPLK knockdown resulted in the same phenotypes as those observed in GW-treated cells. In contrast to Giardia expressing GlPLK-PBD, Giardia expressing GlPLK-KDL was defective in terms of GIPLK localization to mitotic spindles and had altered localization of the basal bodies in dividing cells. Kinase assays using mutant recombinant GlPLKs indicated that mutation at Lys51 or at both Thr179 and Thr183 resulted in loss of kinase activity. Giardia expressing these mutant GlPLKs also demonstrated defects in cell growth, cytokinesis and flagella formation. CONCLUSIONS These data indicate that GlPLK plays a role in Giardia cell division, especially during cytokinesis, and that it is also involved in flagella formation.
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Affiliation(s)
- Eun-Ah Park
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Juri Kim
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Mee Young Shin
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Soon-Jung Park
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722, South Korea.
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Varela PF, Chenon M, Velours C, Verhey KJ, Ménétrey J, Gigant B. Structural snapshots of the kinesin-2 OSM-3 along its nucleotide cycle: implications for the ATP hydrolysis mechanism. FEBS Open Bio 2021; 11:564-577. [PMID: 33513284 PMCID: PMC7931232 DOI: 10.1002/2211-5463.13101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 01/27/2021] [Indexed: 11/09/2022] Open
Abstract
Motile kinesins are motor proteins that translocate along microtubules as they hydrolyze ATP. They share a conserved motor domain which harbors both ATPase and microtubule-binding activities. An ATP hydrolysis mechanism involving two water molecules has been proposed based on the structure of the kinesin-5 Eg5 bound to an ATP analog. Whether this mechanism is general in the kinesin superfamily remains uncertain. Here, we present structural snapshots of the motor domain of OSM-3 along its nucleotide cycle. OSM-3 belongs to the homodimeric kinesin-2 subfamily and is the Caenorhabditis elegans homologue of human KIF17. OSM-3 bound to ADP or devoid of a nucleotide shows features of ADP-kinesins with a docked neck linker. When bound to an ATP analog, OSM-3 adopts a conformation similar to those of several ATP-like kinesins, either isolated or bound to tubulin. Moreover, the OSM-3 nucleotide-binding site is virtually identical to that of ATP-like Eg5, demonstrating a shared ATPase mechanism. Therefore, our data extend to kinesin-2 the two-water ATP hydrolysis mechanism and further suggest that it is universal within the kinesin superfamily. PROTEIN DATABASE ENTRIES: 7A3Z, 7A40, 7A5E.
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Affiliation(s)
- Paloma F Varela
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Mélanie Chenon
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Christophe Velours
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Julie Ménétrey
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Benoît Gigant
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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How Kinesin-1 Utilize the Energy of Nucleotide: The Conformational Changes and Mechanochemical Coupling in the Unidirectional Motion of Kinesin-1. Int J Mol Sci 2020; 21:ijms21186977. [PMID: 32972035 PMCID: PMC7555842 DOI: 10.3390/ijms21186977] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/12/2020] [Accepted: 09/21/2020] [Indexed: 12/23/2022] Open
Abstract
Kinesin-1 is a typical motile molecular motor and the founding member of the kinesin family. The most significant feature in the unidirectional motion of kinesin-1 is its processivity. To realize the fast and processive movement on the microtubule lattice, kinesin-1 efficiently transforms the chemical energy of nucleotide binding and hydrolysis to the energy of mechanical movement. The chemical and mechanical cycle of kinesin-1 are coupled to avoid futile nucleotide hydrolysis. In this paper, the research on the mechanical pathway of energy transition and the regulating mechanism of the mechanochemical cycle of kinesin-1 is reviewed.
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7
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Fingerhut JM, Yamashita YM. mRNA localization mediates maturation of cytoplasmic cilia in Drosophila spermatogenesis. J Cell Biol 2020; 219:e202003084. [PMID: 32706373 PMCID: PMC7480094 DOI: 10.1083/jcb.202003084] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/10/2020] [Accepted: 06/15/2020] [Indexed: 01/26/2023] Open
Abstract
Cytoplasmic cilia, a specialized type of cilia in which the axoneme resides within the cytoplasm rather than within the ciliary compartment, are proposed to allow for the efficient assembly of very long cilia. Despite being found diversely in male gametes (e.g., Plasmodium falciparum microgametocytes and human and Drosophila melanogaster sperm), very little is known about cytoplasmic cilia assembly. Here, we show that a novel RNP granule containing the mRNAs for axonemal dynein motor proteins becomes highly polarized to the distal end of the cilia during cytoplasmic ciliogenesis in Drosophila sperm. This allows for the incorporation of these axonemal dyneins into the axoneme directly from the cytoplasm, possibly by localizing translation. We found that this RNP granule contains the proteins Reptin and Pontin, loss of which perturbs granule formation and prevents incorporation of the axonemal dyneins, leading to sterility. We propose that cytoplasmic cilia assembly requires the precise localization of mRNAs encoding key axonemal constituents, allowing these proteins to incorporate efficiently into the axoneme.
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Affiliation(s)
- Jaclyn M. Fingerhut
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI
- Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Yukiko M. Yamashita
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI
- Life Sciences Institute, University of Michigan, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI
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8
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Hennessey KM, Alas GCM, Rogiers I, Li R, Merritt EA, Paredez AR. Nek8445, a protein kinase required for microtubule regulation and cytokinesis in Giardia lamblia. Mol Biol Cell 2020; 31:1611-1622. [PMID: 32459558 PMCID: PMC7521801 DOI: 10.1091/mbc.e19-07-0406] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Giardia has 198 Nek kinases whereas humans have only 11. Giardia has a complex microtubule cytoskeleton that includes eight flagella and several unique microtubule arrays that are utilized for parasite attachment and facilitation of rapid mitosis and cytokinesis. The need to regulate these structures may explain the parallel expansion of the number of Nek family kinases. Here we use live and fixed cell imaging to uncover the role of Nek8445 in regulating Giardia cell division. We demonstrate that Nek8445 localization is cell cycle regulated and this kinase has a role in regulating overall microtubule organization. Nek8445 depletion results in short flagella, aberrant ventral disk organization, loss of the funis, defective axoneme exit, and altered cell shape. The axoneme exit defect is specific to the caudal axonemes, which exit from the posterior of the cell, and this defect correlates with rounding of the cell posterior and loss of the funis. Our findings implicate a role for the funis in establishing Giardia’s cell shape and guiding axoneme docking. On a broader scale our results support the emerging view that Nek family kinases have a general role in regulating microtubule organization.
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Affiliation(s)
| | - Germain C M Alas
- Department of Biology, University of Washington, Seattle, WA 98195
| | - Ilse Rogiers
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Renyu Li
- Department of Biology, University of Washington, Seattle, WA 98195
| | - Ethan A Merritt
- Department of Biochemistry, University of Washington, Seattle, WA 98195
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Abstract
Giardia intestinalis, the causative agent of giardiasis, has complex cytoskeleton organization with structures involved in motility, adhesion, cell division, and cell differentiation. Microtubules are key components of the cytoskeleton and are the main elements of the ventral disc, median body, funis, in addition to four pairs of flagella. These cytoskeletal elements are basically stable microtubule arrangements. Although tubulins are the main proteins of these elements, molecular and biochemical analyses of Giardia trophozoites have revealed the presence of several new and not yet characterized proteins in these structures, which may contribute to their nanoarchitecture (mainly in the ventral disc). Despite these findings, morphological data are still required for understanding the organization and biogenesis of the cytoskeletal structures. In the study of this complex and specialized network of filaments in Giardia, two distinct and complementary approaches have been used in recent years: (a) transmission electron microscopy tomography of conventionally processed as well as cryo-fixed samples and (b) high-resolution scanning electron microscopy and helium ion microscopy in combination with new plasma membrane extraction protocols. In this review we include the most recent studies that have allowed better understanding of new Giardia components and their association with other filamentous structures of this parasite, thus providing new insights in the role of the cytoskeletal structures and their function in Giardia trophozoites.
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Hagen KD, McInally SG, Hilton ND, Dawson SC. Microtubule organelles in Giardia. ADVANCES IN PARASITOLOGY 2020; 107:25-96. [PMID: 32122531 DOI: 10.1016/bs.apar.2019.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Giardia lamblia is a widespread parasitic protist with a complex MT cytoskeleton that is critical for motility, attachment, mitosis and cell division, and transitions between its two life cycle stages-the infectious cyst and flagellated trophozoite. Giardia trophozoites have both highly dynamic and highly stable MT organelles, including the ventral disc, eight flagella, the median body and the funis. The ventral disc, an elaborate MT organelle, is essential for the parasite's attachment to the intestinal villi to avoid peristalsis. Giardia's four flagellar pairs enable swimming motility and may also promote attachment. They are maintained at different equilibrium lengths and are distinguished by their long cytoplasmic regions and novel extra-axonemal structures. The functions of the median body and funis, MT organelles unique to Giardia, remain less understood. In addition to conserved MT-associated proteins, the genome is enriched in ankyrins, NEKs, and novel hypothetical proteins that also associate with the MT cytoskeleton. High-resolution ultrastructural imaging and a current inventory of more than 300 proteins associated with Giardia's MT cytoskeleton lay the groundwork for future mechanistic analyses of parasite attachment to the host, motility, cell division, and encystation/excystation. Giardia's unique MT organelles exemplify the capacity of MT polymers to generate intricate structures that are diverse in both form and function. Thus, beyond its relevance to pathogenesis, the study of Giardia's MT cytoskeleton informs basic cytoskeletal biology and cellular evolution. With the availability of new molecular genetic tools to disrupt gene function, we anticipate a new era of cytoskeletal discovery in Giardia.
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Affiliation(s)
- Kari D Hagen
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States
| | - Shane G McInally
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States
| | - Nicholas D Hilton
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States.
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Jex AR, Svärd S, Hagen KD, Starcevich H, Emery-Corbin SJ, Balan B, Nosala C, Dawson SC. Recent advances in functional research in Giardia intestinalis. ADVANCES IN PARASITOLOGY 2020; 107:97-137. [PMID: 32122532 PMCID: PMC7878119 DOI: 10.1016/bs.apar.2019.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This review considers current advances in tools to investigate the functional biology of Giardia, it's coding and non-coding genes, features and cellular and molecular biology. We consider major gaps in current knowledge of the parasite and discuss the present state-of-the-art in its in vivo and in vitro cultivation. Advances in in silico tools, including for the modelling non-coding RNAs and genomic elements, as well as detailed exploration of coding genes through inferred homology to model organisms, have provided significant, primary level insight. Improved methods to model the three-dimensional structure of proteins offer new insights into their function, and binding interactions with ligands, other proteins or precursor drugs, and offer substantial opportunities to prioritise proteins for further study and experimentation. These approaches can be supplemented by the growing and highly accessible arsenal of systems-based methods now being applied to Giardia, led by genomic, transcriptomic and proteomic methods, but rapidly incorporating advanced tools for detection of real-time transcription, evaluation of chromatin states and direct measurement of macromolecular complexes. Methods to directly interrogate and perturb gene function have made major leaps in recent years, with CRISPr-interference now available. These approaches, coupled with protein over-expression, fluorescent labelling and in vitro and in vivo imaging, are set to revolutionize the field and herald an exciting time during which the field may finally realise Giardia's long proposed potential as a model parasite and eukaryote.
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Affiliation(s)
- Aaron R Jex
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia.
| | - Staffan Svärd
- Centre for Biomedicine, Uppsala University, Uppsala, Sweden
| | - Kari D Hagen
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Hannah Starcevich
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Samantha J Emery-Corbin
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Balu Balan
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Chris Nosala
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Scott C Dawson
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
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12
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Bertiaux E, Bastin P. Dealing with several flagella in the same cell. Cell Microbiol 2020; 22:e13162. [DOI: 10.1111/cmi.13162] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/19/2019] [Indexed: 01/16/2023]
Affiliation(s)
- Eloïse Bertiaux
- Trypanosome Cell Biology Unit INSERM U1201, Institut Pasteur Paris France
- École Doctorale Complexité du Vivant Sorbonne Université Paris France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit INSERM U1201, Institut Pasteur Paris France
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13
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McInally SG, Kondev J, Dawson SC. Length-dependent disassembly maintains four different flagellar lengths in Giardia. eLife 2019; 8:e48694. [PMID: 31855176 PMCID: PMC6992383 DOI: 10.7554/elife.48694] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 12/18/2019] [Indexed: 01/03/2023] Open
Abstract
With eight flagella of four different lengths, the parasitic protist Giardia is an ideal model to evaluate flagellar assembly and length regulation. To determine how four different flagellar lengths are maintained, we used live-cell quantitative imaging and mathematical modeling of conserved components of intraflagellar transport (IFT)-mediated assembly and kinesin-13-mediated disassembly in different flagellar pairs. Each axoneme has a long cytoplasmic region extending from the basal body, and transitions to a canonical membrane-bound flagellum at the 'flagellar pore'. We determined that each flagellar pore is the site of IFT accumulation and injection, defining a diffusion barrier functionally analogous to the transition zone. IFT-mediated assembly is length-independent, as train size, speed, and injection frequencies are similar for all flagella. We demonstrate that kinesin-13 localization to the flagellar tips is inversely correlated to flagellar length. Therefore, we propose a model where a length-dependent disassembly mechanism controls multiple flagellar lengths within the same cell.
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Affiliation(s)
- Shane G McInally
- Department of Microbiology and Molecular GeneticsUniversity of California, DavisDavisUnited States
| | - Jane Kondev
- Department of PhysicsBrandeis UniversityWalthamUnited States
| | - Scott C Dawson
- Department of Microbiology and Molecular GeneticsUniversity of California, DavisDavisUnited States
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14
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Lin ZL, Li YH, Jin YX, Kim NH. A Maternal Transcription Factor, Junction Mediating and Regulatory
Protein is Required for Preimplantation Development in the Mouse. Dev Reprod 2019; 23:285-295. [PMID: 31660455 PMCID: PMC6812975 DOI: 10.12717/dr.2019.23.3.285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/05/2019] [Accepted: 08/29/2019] [Indexed: 11/21/2022]
Abstract
Junction-mediating and regulatory protein (JMY) is a regulator of both
transcription and actin filament assembly. The actin-regulatory activity of JMY
is based on a cluster of three actin-binding Wiskott-Aldrich syndrome protein
homology 2 (WH2) domains that nucleate actin filaments directly and promote
nucleation of the Arp2/3 complex. In addition to these activities, we examined
the activity of JMY generation in early embryo of mice carrying mutations in the
JMY gene by CRISPR/Cas9 mediated genome engineering. We demonstrated that JMY
protein shuttled expression between the cytoplasm and the nucleus. Knockout of
exon 2, CA (central domain and Arp2/3-binding acidic domain) and NLS-2 (nuclear
localization signal domain) on the JMY gene by CRISPR/Cas9
system was effective and markedly impeded embryonicdevelopment. Additionally, it
impaired transcription and zygotic genome activation (ZGA)-related genes. These
results suggest that JMY acts as a transcription factor, which is essential for
the early embryonic development in mice.
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Affiliation(s)
- Zi-Li Lin
- College of Animal Sciences, Jilin
University, Changchun, China
- School of Life Sciences, Tsinghua
University, Beijing 100084, China
| | - Ying-Hua Li
- Department of Animal Sciences, Yanbian
University, Yanji, Jilin Province,
China
| | - Yong-Xun Jin
- College of Animal Sciences, Jilin
University, Changchun, China
- Corresponding Author : Nam-Hyung Kim, Ph.D.,
Department of Animal Sciences, Chungbuk National University, Cheongju 28644,
Korea. Tel: +82-43-261-2546, E-mail:
, Yong-Xun Jin, College of Animal
Sciences, Jilin University, Changchun, China. Tel:
+86-431-8516-6316, E-mail:
| | - Nam-Hyung Kim
- College of Animal Sciences, Jilin
University, Changchun, China
- Department of Animal Sciences, Chungbuk National
University, Cheongju 28644, Korea
- Corresponding Author : Nam-Hyung Kim, Ph.D.,
Department of Animal Sciences, Chungbuk National University, Cheongju 28644,
Korea. Tel: +82-43-261-2546, E-mail:
, Yong-Xun Jin, College of Animal
Sciences, Jilin University, Changchun, China. Tel:
+86-431-8516-6316, E-mail:
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15
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Chen B, Shan T. The role of satellite and other functional cell types in muscle repair and regeneration. J Muscle Res Cell Motil 2019; 40:1-8. [PMID: 30968305 DOI: 10.1007/s10974-019-09511-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 04/04/2019] [Indexed: 12/21/2022]
Abstract
Skeletal muscles play essential roles in physiological processes, including motor function, energy hemostasis, and respiration. Skeletal muscles also have the capacity to regenerate after injury. Regeneration of skeletal muscle is an extremely complex biological process, which involves multiple cell types. Skeletal muscle stem cells (also known as satellite cells; SCs) are crucial for the development, growth, maintenance and repair of the skeletal muscle. Cell fates and function have been extensively studied in the context of skeletal muscle regeneration. In addition to SCs, other cell types, such as fibro-adipogenic precursors (FAPs), endothelial cells, fibroblasts, pericytes and certain immune cells, play important regulatory roles during skeletal muscle regeneration. In this review, we summarize and discuss the current research progress on the different cell types and their respective functions in skeletal muscle regeneration and repair.
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Affiliation(s)
- Bide Chen
- College of Animal Sciences, Zhejiang University; The Key Laboratory of Molecular Animal Nutrition, Ministry of Education; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Tizhong Shan
- College of Animal Sciences, Zhejiang University; The Key Laboratory of Molecular Animal Nutrition, Ministry of Education; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, People's Republic of China.
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16
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McInally SG, Hagen KD, Nosala C, Williams J, Nguyen K, Booker J, Jones K, Dawson SC. Robust and stable transcriptional repression in Giardia using CRISPRi. Mol Biol Cell 2018; 30:119-130. [PMID: 30379614 PMCID: PMC6337905 DOI: 10.1091/mbc.e18-09-0605] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Giardia lamblia is a binucleate protistan parasite causing significant diarrheal disease worldwide. An inability to target Cas9 to both nuclei, combined with the lack of nonhomologous end joining and markers for positive selection, has stalled the adaptation of CRISPR/Cas9-mediated genetic tools for this widespread parasite. CRISPR interference (CRISPRi) is a modification of the CRISPR/Cas9 system that directs catalytically inactive Cas9 (dCas9) to target loci for stable transcriptional repression. Using a Giardia nuclear localization signal to target dCas9 to both nuclei, we developed efficient and stable CRISPRi-mediated transcriptional repression of exogenous and endogenous genes in Giardia. Specifically, CRISPRi knockdown of kinesin-2a and kinesin-13 causes severe flagellar length defects that mirror defects with morpholino knockdown. Knockdown of the ventral disk MBP protein also causes severe structural defects that are highly prevalent and persist in the population more than 5 d longer than defects associated with transient morpholino-based knockdown. By expressing two guide RNAs in tandem to simultaneously knock down kinesin-13 and MBP, we created a stable dual knockdown strain with both flagellar length and disk defects. The efficiency and simplicity of CRISPRi in polyploid Giardia allows rapid evaluation of knockdown phenotypes and highlights the utility of CRISPRi for emerging model systems.
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Affiliation(s)
- S G McInally
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K D Hagen
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - C Nosala
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - J Williams
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K Nguyen
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - J Booker
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K Jones
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
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17
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Harmer J, Qi X, Toniolo G, Patel A, Shaw H, Benson FE, Ginger ML, McKean PG. Variation in Basal Body Localisation and Targeting of Trypanosome RP2 and FOR20 Proteins. Protist 2017; 168:452-466. [PMID: 28822909 DOI: 10.1016/j.protis.2017.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 06/28/2017] [Accepted: 07/01/2017] [Indexed: 12/22/2022]
Abstract
TOF-LisH-PLL motifs define FOP family proteins; some members are involved in flagellum assembly. The critical role of FOP family protein FOR20 is poorly understood. Here, we report relative localisations of the four FOP family proteins in parasitic Trypanosoma brucei: TbRP2, TbOFD1 and TbFOP/FOP1-like are mature basal body proteins whereas TbFOR20 is present on pro- and mature basal bodies - on the latter it localises distal to TbRP2. We discuss how the data, together with published work for another protist Giardia intestinalis, informs on likely FOR20 function. Moreover, our localisation study provides convincing evidence that the antigen recognised by monoclonal antibody YL1/2 at trypanosome mature basal bodies is FOP family protein TbRP2, not tyrosinated α-tubulin as widely stated in the literature. Curiously, FOR20 proteins from T. brucei and closely related African trypanosomes possess short, negatively-charged N-terminal extensions absent from FOR20 in other trypanosomatids and other eukaryotes. The extension is necessary for protein targeting, but insufficient to re-direct TbRP2 to probasal bodies. Yet, FOR20 from the American trypanosome T. cruzi, which lacks any extension, localises to pro- and mature basal bodies when expressed in T. brucei. This identifies unexpected variation in FOR20 architecture that is presently unique to one clade of trypanosomatids.
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Affiliation(s)
- Jane Harmer
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Xin Qi
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Gabriella Toniolo
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Aysha Patel
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Hannah Shaw
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Fiona E Benson
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Michael L Ginger
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Paul G McKean
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK.
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18
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Abstract
Most motile and all non-motile (also known as primary) eukaryotic cilia possess microtubule-based axonemes that are assembled at the cell surface to form hair-like or more elaborate compartments endowed with motility and/or signaling functions. Such compartmentalized ciliogenesis depends on the core intraflagellar transport (IFT) machinery and the associated Bardet-Biedl syndrome complex (BBSome) for dynamic delivery of ciliary components. The transition zone (TZ), an ultrastructurally complex barrier or 'gate' at the base of cilia, also contributes to the formation of compartmentalized cilia. Yet, some ciliated protists do not have IFT components and, like some metazoan spermatozoa, use IFT-independent mechanisms to build axonemes exposed to the cytosol. Moreover, various ciliated protists lack TZ components, whereas Drosophila sperm surprisingly requires the activity of dynamically localized TZ proteins for cytosolic ciliogenesis. Here, we discuss the various ways eukaryotes use IFT and/or TZ proteins to generate the wide assortment of compartmentalized and cytosolic cilia observed in nature. Consideration of the different ciliogenesis pathways allows us to propose how three types of cytosol-exposed cilia (primary, secondary and tertiary), including cilia found in the human sperm proximal segment, are likely generated by evolutionary derivations of compartmentalized ciliogenesis.
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19
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McInally SG, Dawson SC. Eight unique basal bodies in the multi-flagellated diplomonad Giardia lamblia. Cilia 2016; 5:21. [PMID: 27379179 PMCID: PMC4931700 DOI: 10.1186/s13630-016-0042-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 04/20/2016] [Indexed: 12/16/2022] Open
Abstract
Giardia lamblia is an intestinal parasitic protist that causes significant acute and chronic diarrheal disease worldwide. Giardia belongs to the diplomonads, a group of protists in the supergroup Excavata. Diplomonads are characterized by eight motile flagella organized into four bilaterally symmetric pairs. Each of the eight Giardia axonemes has a long cytoplasmic region that extends from the centrally located basal body before exiting the cell body as a membrane-bound flagellum. Each basal body is thus unique in its cytological position and its association with different cytoskeletal features, including the ventral disc, axonemes, and extra-axonemal structures. Inheritance of these unique and complex cytoskeletal elements is maintained through basal body migration, duplication, maturation, and their subsequent association with specific spindle poles during cell division. Due to the complex composition and inheritance of specific basal bodies and their associated structures, Giardia may require novel basal body-associated proteins. Thus, protists such as Giardia may represent an undiscovered source of novel basal body-associated proteins. The development of new tools that make Giardia genetically tractable will enable the composition, structure, and function of the eight basal bodies to be more thoroughly explored.
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Affiliation(s)
- Shane G McInally
- Department of Microbiology and Molecular Genetics, University of California Davis, One Shields Avenue, Davis, CA 95616 USA
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California Davis, One Shields Avenue, Davis, CA 95616 USA
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20
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The Critical Role of the Cytoskeleton in the Pathogenesis of Giardia. CURRENT CLINICAL MICROBIOLOGY REPORTS 2015; 2:155-162. [PMID: 27347476 DOI: 10.1007/s40588-015-0026-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Giardia lamblia is a flagellated parasite of the gut and causes significant morbidity worldwide. Novel druggable targets are sorely needed due to Giardia's prevalence and the growing threat of antibiotic resistance. Giardia's conserved and unique cytoskeletal features, such as its eight flagella and ventral disc, are required for host colonization by facilitating motility, attachment, and cell division. Therapies that target these processes could interfere with trophozoite colonization, reduce the time or severity of the infection, and reduce the number of infectious cysts shed into the environment. This requires vetting and prioritizing critical cellular processes and identifying specific Giardia proteins in those processes as targets. It is time to leverage the wealth of data gathered through genome sequencing and proteomic studies, and new insights on the cytoskeleton of Giardia to design effective new drugs to treat giardiasis.
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21
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Cochran JC. Kinesin Motor Enzymology: Chemistry, Structure, and Physics of Nanoscale Molecular Machines. Biophys Rev 2015; 7:269-299. [PMID: 28510227 DOI: 10.1007/s12551-014-0150-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 11/16/2014] [Indexed: 11/25/2022] Open
Abstract
Molecular motors are enzymes that convert chemical potential energy into controlled kinetic energy for mechanical work inside cells. Understanding the biophysics of these motors is essential for appreciating life as well as apprehending diseases that arise from motor malfunction. This review focuses on kinesin motor enzymology with special emphasis on the literature that reports the chemistry, structure and physics of several different kinesin superfamily members.
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Affiliation(s)
- J C Cochran
- Department of Molecular & Cellular Biochemistry, Indiana University, Simon Hall Room 405C, 212 S. Hawthorne Dr., Bloomington, IN, 47405, USA.
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22
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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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23
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Alternative cytoskeletal landscapes: cytoskeletal novelty and evolution in basal excavate protists. Curr Opin Cell Biol 2013; 25:134-41. [PMID: 23312067 DOI: 10.1016/j.ceb.2012.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/18/2012] [Accepted: 11/20/2012] [Indexed: 11/24/2022]
Abstract
Microbial eukaryotes encompass the majority of eukaryotic evolutionary and cytoskeletal diversity. The cytoskeletal complexity observed in multicellular organisms appears to be an expansion of components present in genomes of diverse microbial eukaryotes such as the basal lineage of flagellates, the Excavata. Excavate protists have complex and diverse cytoskeletal architectures and life cycles-essentially alternative cytoskeletal 'landscapes'-yet still possess conserved microtubule-associated and actin-associated proteins. Comparative genomic analyses have revealed that a subset of excavates, however, lack many canonical actin-binding proteins central to actin cytoskeleton function in other eukaryotes. Overall, excavates possess numerous uncharacterized and 'hypothetical' genes, and may represent an undiscovered reservoir of novel cytoskeletal genes and cytoskeletal mechanisms. The continued development of molecular genetic tools in these complex microbial eukaryotes will undoubtedly contribute to our overall understanding of cytoskeletal diversity and evolution.
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24
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Stable transfection of the diplomonad parasite Spironucleus salmonicida. EUKARYOTIC CELL 2012; 11:1353-61. [PMID: 22983987 DOI: 10.1128/ec.00179-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Eukaryotic microbes are highly diverse, and many lineages remain poorly studied. One such lineage, the diplomonads, a group of binucleate heterotrophic flagellates, has been studied mainly due to the impact of Giardia intestinalis, an intestinal, diarrhea-causing parasite in humans and animals. Here we describe the development of a stable transfection system for use in Spironucleus salmonicida, a diplomonad that causes systemic spironucleosis in salmonid fish. We designed vectors in cassette format carrying epitope tags for localization (3×HA [where HA is hemagglutinin], 2× Escherichia coli OmpF linker and mouse langerin fusion sequence [2×OLLAS], 3×MYC) and purification of proteins (2× Strep-Tag II-FLAG tandem-affinity purification tag or streptavidin binding peptide-glutathione S-transferase [SBP-GST]) under the control of native or constitutive promoters. Three selectable gene markers, puromycin acetyltransferase (pac), blasticidin S-deaminase (bsr), and neomycin phosphotransferase (nptII), were successfully applied for the generation of stable transfectants. Site-specific integration on the S. salmonicida chromosome was shown to be possible using the bsr resistance gene. We epitope tagged six proteins and confirmed their expression by Western blotting. Next, we demonstrated the utility of these vectors by recording the subcellular localizations of the six proteins by laser scanning confocal microscopy. Finally, we described the creation of an S. salmonicida double transfectant suitable for colocalization studies. The transfection system described herein and the imminent completion of the S. salmonicida genome will make it possible to use comparative genomics as an investigative tool to explore specific, as well as general, diplomonad traits, benefiting research on both Giardia and Spironucleus.
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25
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Fisch C, Dupuis-Williams P. [The rebirth of the ultrastructure of cilia and flagella]. Biol Aujourdhui 2012; 205:245-67. [PMID: 22251859 DOI: 10.1051/jbio/2011023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Indexed: 11/14/2022]
Abstract
The sensory and motility functions of eukaryotic cilia and flagella are essential for cell survival in protozoans and for cell differentiation and homoeostasis in metazoans. Ciliary biology has benefited early on from the input of electron microscopy. Over the last decade, the visualization of cellular structures has greatly progressed, thus it becomes timely to review the ultrastructure of cilia and flagella. Briefly touching upon the typical features of a 9+2 axoneme, we dwell extensively on the transition zone, the singlet zone, the ciliary necklace, cap and crown. The relation of the singlet zone to sensory and/or motile function, the link of the ciliary cap to microtubule dynamics and to ciliary beat, the involvement of the ciliary crown in ovocyte and mucosal propulsion, and the role of the transition zone/the ciliary necklace in axonemal stabilization, autotomy and as a diffusion barrier will all be discussed.
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Affiliation(s)
- Cathy Fisch
- ATIGE Centriole et Pathologies Associées, INSERM/UEVE U829, 91000 Évry, France.
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26
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Konno A, Setou M, Ikegami K. Ciliary and flagellar structure and function--their regulations by posttranslational modifications of axonemal tubulin. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 294:133-70. [PMID: 22364873 DOI: 10.1016/b978-0-12-394305-7.00003-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Eukaryotic cilia and flagella are evolutionarily conserved microtubule-based organelles protruding from the cell surface. They perform dynein-driven beating which contributes to cell locomotion or flow generation. They also play important roles in sensing as cellular antennae, which allows cells to respond to various external stimuli. The main components of cilia and flagella, α- and β-tubulins, are known to undergo various posttranslational modifications (PTMs), including phosphorylation, palmitoylation, tyrosination/detyrosination, Δ2 modification, acetylation, glutamylation, and glycylation. Recent identification of tubulin-modifying enzymes, especially tubulin tyrosine ligase-like proteins which perform tubulin glutamylation and glycylation, has demonstrated the importance of tubulin modifications for the assembly and functions of cilia and flagella. In this chapter, we review recent work on PTMs of ciliary and flagellar tubulins in conjunction with discussing the basic knowledge.
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Affiliation(s)
- Alu Konno
- Department of Cell Biology and Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
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27
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Abstract
Eukaryotic cilia and flagella perform motility and sensory functions which are essential for cell survival in protozoans, and to organism development and homoeostasis in metazoans. Their ultrastructure has been studied from the early beginnings of electron microscopy, and these studies continue to contribute to much of our understanding about ciliary biology. In the light of the progress made in the visualization of cellular structures over the last decade, we revisit the ultrastructure of cilia and flagella. We briefly describe the typical features of a 9+2 axoneme before focusing extensively on the transition zone, the ciliary necklace, the singlet zone, the ciliary cap and the ciliary crown. We discuss how the singlet zone is linked to sensory and/or motile function, the contribution of the ciliary crown to ovocyte and mucosal propulsion, and the relationship between the ciliary cap and microtubule growth and shortening, and its relation to ciliary beat. We further examine the involvement of the transition zone/the ciliary necklace in axonemal stabilization, autotomy and as a diffusion barrier.
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28
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Naber N, Larson A, Rice S, Cooke R, Pate E. Multiple conformations of the nucleotide site of Kinesin family motors in the triphosphate state. J Mol Biol 2011; 408:628-42. [PMID: 21277856 DOI: 10.1016/j.jmb.2011.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 12/04/2010] [Accepted: 01/03/2011] [Indexed: 10/18/2022]
Abstract
Identifying conformational changes in kinesin family motors associated with nucleotide and microtubule (MT) binding is essential to determining an atomic-level model for force production and motion by the motors. Using the mobility of nucleotide analog spin probes bound at the active sites of kinesin family motors to monitor conformational changes, we previously demonstrated that, in the ADP state, the open nucleotide site closes upon MT binding [Naber, N., Minehardt, T. J., Rice, S., Chen, X., Grammer, J., Matuska, M., et al. (2003). Closing of the nucleotide pocket of kinesin family motors upon binding to microtubules. Science, 300, 798-801]. We now extend these studies to kinesin-1 (K) and ncd (nonclaret disjunctional protein) motors in ATP and ATP-analog states. Our results reveal structural differences between several triphosphate and transition-state analogs bound to both kinesin and ncd in solution. The spectra of kinesin/ncd in the presence of SLADP•AlFx/BeFx and kinesin, with the mutation E236A (K-E236A; does not hydrolyze ATP) bound to ATP, show an open conformation of the nucleotide pocket similar to that seen in the kinesin/ncd•ADP states. In contrast, the triphosphate analogs K•SLAMPPNP and K-E236A•SLAMPPNP induce a more immobilized component of the electron paramagnetic resonance spectrum, implying closing of the nucleotide site. The MT-bound states of all of the triphosphate analogs reveal two novel spectral components. The equilibrium between these two components is only weakly dependent on temperature. Both components have more restricted mobility than observed in MT-bound diphosphate states. Thus, the closing of the nucleotide pocket when the diphosphate state binds to MTs is amplified in the triphosphate state, perhaps promoting accelerated ATP hydrolysis. Consistent with this idea, molecular dynamics simulations show a good correlation between our spectroscopic data, X-ray crystallography, and the electron microscopy of MT-bound triphosphate-analog states.
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Affiliation(s)
- Nariman Naber
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
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29
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Life with eight flagella: flagellar assembly and division in Giardia. Curr Opin Microbiol 2010; 13:480-90. [PMID: 20580308 DOI: 10.1016/j.mib.2010.05.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 05/26/2010] [Accepted: 05/27/2010] [Indexed: 11/23/2022]
Abstract
Flagellar movement in Giardia, a common intestinal parasitic protist, is crucial to its survival in the host. Each axoneme is unique in possessing a long, cytoplasmic portion as well as a membrane-bound portion. Intraflagellar transport (IFT) is required for the assembly of membrane-bound regions, yet the cytoplasmic regions may be assembled by IFT-independent mechanisms. Steady-state axoneme length is maintained by IFT and by intrinsic and active microtubule dynamics. Following mitosis and before their segregation, giardial flagella undergo a multigenerational division cycle in which the parental eight flagella migrate and reposition to different cellular locations; eight new flagella are assembled de novo. Each daughter cell thus inherits four mature and four newly synthesized flagella.
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30
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31
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32
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Abstract
Giardia intestinalis, a common parasitic protist, possesses a complex microtubule cytoskeleton critical for cellular function and transitioning between the cyst and trophozoite life cycle stages. The giardial microtubule cytoskeleton is comprised of highly dynamic and stable structures. Novel microtubule structures include the ventral disc that is essential for the parasite's attachment to the intestinal villi to avoid peristalsis. The completed Giardia genome combined with new molecular genetic tools and live imaging will aid in the characterization and analysis of cytoskeletal dynamics in Giardia. Fundamental areas of giardial cytoskeletal biology remain to be explored and knowledge of the molecular mechanisms of cytoskeletal functioning is needed to better understand Giardia's unique biology and pathogenesis.
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Affiliation(s)
- Scott C Dawson
- Department of Microbiology, One Shields Avenue, UC Davis, Davis, CA 95616, USA
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33
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The mechanisms of kinesin motor motility: lessons from the monomeric motor KIF1A. Nat Rev Mol Cell Biol 2009; 10:877-84. [PMID: 19935670 DOI: 10.1038/nrm2807] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Most kinesins move processively along microtubules by using energy derived from ATP hydrolysis. Almost all of the intermediate structures of this ATPase reaction cycle have been solved for the monomeric kinesin 3 family motor KIF1A. Based on this structural information, we propose a common mechanism of kinesin motility, focusing on the regulation of kinesin motility through their interaction with microtubules and by their 'neck-linker' region, which connects their motor domain to cargo and kinesin partner heads.
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34
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Dual acylation accounts for the localization of {alpha}19-giardin in the ventral flagellum pair of Giardia lamblia. EUKARYOTIC CELL 2009; 8:1567-74. [PMID: 19684283 DOI: 10.1128/ec.00136-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A Giardia-specific protein family denominated as alpha-giardins, represents the major protein component, besides tubulin, of the cytoskeleton of the human pathogenic parasite Giardia lamblia. One of its members, alpha19-giardin, carries an N-terminal sequence extension of MGCXXS, which in many proteins serves as a target for dual lipid conjugation: myristoylation at the glycine residue after removal of the methionine and palmitoylation at the cysteine residue. As the first experimental evidence of a lipid modification, we found alpha19-giardin to be associated with the membrane fraction of disrupted trophozoites. After heterologous coexpression of alpha19-giardin with giardial N-myristoyltransferase (NMT) in Escherichia coli, we found the protein in a myristoylated form. Additionally, after heterologous expression together with the palmitoyl transferase Pfa3 in Saccharomyces cerevisiae, alpha19-giardin associates with the membrane of the main vacuole. Immunocytochemical colocalization studies on wild-type Giardia trophozoites with tubulin provide evidence that alpha19-giardin exclusively localizes to the ventral pair of the giardial flagella. A mutant in which the putatively myristoylated N-terminal glycine residue was replaced by alanine lost this specific localization. Our findings suggest that the dual lipidation of alpha19-giardin is responsible for its specific flagellar localization.
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Muthukrishnan G, Zhang Y, Shastry S, Hancock WO. The processivity of kinesin-2 motors suggests diminished front-head gating. Curr Biol 2009; 19:442-7. [PMID: 19278641 DOI: 10.1016/j.cub.2009.01.058] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 01/19/2009] [Accepted: 01/20/2009] [Indexed: 11/15/2022]
Abstract
Kinesin-2 motors, which are involved in intraflagellar transport and cargo transport along cytoplasmic microtubules, differ from motors in the canonical kinesin-1 family by having a heterodimeric rather than homodimeric structure and possessing a three amino acid insertion in their neck linker domain. To determine how these structural features alter the chemomechanical coupling in kinesin-2, we used single-molecule bead experiments to measure the processivity and velocity of mouse kinesin-2 heterodimer (KIF3A/B) and the engineered homodimers KIF3A/A and KIF3B/B and compared their behavior to Drosophila kinesin-1 heavy chain (KHC). Single-motor run lengths of kinesin-2 were 4-fold shorter than those of kinesin-1. Extending the kinesin-1 neck linker by three amino acids led to a similar reduction in processivity. Furthermore, kinesin-2 processivity varied inversely with ATP concentration. Stochastic simulations of the kinesin-1 and kinesin-2 hydrolysis cycles suggest that "front-head gating," in which rearward tension prevents ATP binding to the front head when both heads are bound to the microtubule, is diminished in kinesin-2. Because the mechanical tension that underlies front-head gating must be transmitted through the neck linker domains, we propose that the diminished coordination in kinesin-2 is a result of its longer and, hence, more compliant neck linker element.
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Affiliation(s)
- Gayatri Muthukrishnan
- Department of Bioengineering, The Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802, USA
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Carpenter ML, Cande WZ. Using morpholinos for gene knockdown in Giardia intestinalis. EUKARYOTIC CELL 2009; 8:916-9. [PMID: 19377039 PMCID: PMC2698301 DOI: 10.1128/ec.00041-09] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 04/02/2009] [Indexed: 11/20/2022]
Abstract
We used translation-blocking morpholinos to reduce protein levels in Giardia intestinalis. Twenty-four hours after electroporation with morpholinos targeting either green fluorescent protein or kinesin-2b, levels of these proteins were reduced by 60%. An epitope-tagged transgene can also be used as a reporter for morpholino efficacy with targets lacking specific antibodies.
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Affiliation(s)
- Meredith L Carpenter
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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Hariharan V, Hancock WO. Insights into the Mechanical Properties of the Kinesin Neck Linker Domain from Sequence Analysis and Molecular Dynamics Simulations. Cell Mol Bioeng 2009; 2:177-189. [PMID: 21544223 DOI: 10.1007/s12195-009-0059-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The 14-18 amino acid kinesin neck linker domain links the core motor to the coiled-coil dimerization domain. One puzzle is that the neck linker appears too short for the 4 nm distance each linker must stretch to enable an 8 nm step - when modeled as an entropic spring, high inter-head forces are predicted when both heads are bound to the microtubule. We addressed this by analyzing the length of the neck linker across different kinesin families and using molecular dynamics simulations to model the extensibility of Kinesin-1 and Kinesin-2 neck linkers. The force-extension profile from molecular dynamics agrees with the Worm Like Chain (WLC) model for Kinesin-1 and supports the puzzling prediction that extending the neck linker 4 nm requires forces multiple times the motor stall force. Despite being 3 amino acids longer, simulations suggest that extending the Kinesin-2 neck linker by 4 nm requires similarly high forces. A possible resolution to this dilemma is that helix α-6 may unwind to enable the two-head bound state. Finally, simulations suggest that cis/trans isomerization of a conserved proline residue in Kinesin-2 accounts for the differing predictions of molecular dynamics and the WLC model, and may contribute to motor regulation in vivo.
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Affiliation(s)
- Venkatesh Hariharan
- Department of Bioengineering, The Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802
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Abstract
In unicellular and multicellular eukaryotes, fast cell motility and rapid movement of material over cell surfaces are often mediated by ciliary or flagellar beating. The conserved defining structure in most motile cilia and flagella is the '9+2' microtubule axoneme. Our general understanding of flagellum assembly and the regulation of flagellar motility has been led by results from seminal studies of flagellate protozoa and algae. Here we review recent work relating to various aspects of protist physiology and cell biology. In particular, we discuss energy metabolism in eukaryotic flagella, modifications to the canonical assembly pathway and flagellum function in parasite virulence.
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