Microtubule Motors: Intracellular Transport, Cell Division, Ciliary Movement, and Nuclear Migration

2016 ◽  
pp. 1212-1216
Author(s):  
Anthony J. Wynshaw-Boris
Keyword(s):  
Cell Division ◽  
Intracellular Transport ◽  
Nuclear Migration ◽  
Ciliary Movement ◽  
Microtubule Motors

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

scholarly journals Plasmodium Kinesin-8X associates with mitotic spindles and is essential for oocyst development during parasite proliferation and transmission

2019 ◽  
Author(s):  
Mohammad Zeeshan ◽  
Fiona Shilliday ◽  
Tianyang Liu ◽  
Steven Abel ◽  
Tobias Mourier ◽  
...  
Keyword(s):  
Life Cycle ◽  
Cell Division ◽  
Gene Targeting ◽  
Intracellular Transport ◽  
Regulation Of Gene Expression ◽  
Microtubule Depolymerization ◽  
Expression Of Genes ◽  
Genome Wide ◽  
Spindle Dynamics ◽  
Chromosome Alignment

AbstractKinesin-8 proteins are microtubule motors that are often involved in regulation of mitotic spindle length and chromosome alignment. They move towards the ends of spindle microtubules and regulate the dynamics of these ends due, at least in some species, to their microtubule depolymerization activity. Plasmodium spp. exhibit an atypical endomitotic cell division in which chromosome condensation and spindle dynamics are not well understood in the different proliferative stages. Genome-wide homology analysis of Plasmodium spp. revealed the presence of two Kinesin-8 motor proteins (Kinesin-8X and Kinesin-8B). Here we have studied the biochemical properties of Kinesin-8X and its role in parasite proliferation. In vitro, Kinesin-8X showed motile and depolymerization activities like other Kinesin-8 motors. To understand its role in cell division, we have used protein tagging and live cell imaging to define the location of Plasmodium Kinesin-8X during all proliferative stages of the P berghei life cycle. Furthermore, we have used gene targeting to analyse the function of Kinesin-8X. The results reveal a spatio-temporal involvement of Kinesin-8X in spindle dynamics and its association with both mitotic and meiotic spindles and the putative microtubule organising centre (MTOC). Deletion of the Kinesin-8X gene showed that this protein is required for endomitotic division during oocyst development and is therefore necessary for parasite replication within the mosquito gut, and for transmission to the vertebrate host. Consistently, transcriptome analysis of Δkinesin-8X parasites reveals modulated expression of genes involved mainly in microtubule-based processes, chromosome organisation and the regulation of gene expression supporting a role in cell division.Author SummaryKinesins are microtubule-based motors that play key roles in intracellular transport, cell division and motility. Members of the Kinesin-8 family contribute to chromosome alignment during cell division in many eukaryotes. However, the roles of kinesins in the atypical cell division in Plasmodium, the causative agent of malaria, is not known. In contrast to many other eukaryotes, Plasmodium proliferates by endomitosis, in which genome replication and division occur within a nucleus bounded by a persistent nuclear envelope. We show that the Plasmodium genome encodes only nine kinesins and we further investigate the role of Kinesin-8X throughout the Plasmodium life cycle using biochemical and gene targeting approaches. We show that Plasmodium Kinesin-8X has microtubule-based motility and depolymerization activity. We also show that Kinesin-8X is probably localized on putative MTOCs and spindles during cell division in most of the stages of P. berghei life cycle. By gene deletion we demonstrate that Kinesin-8X is essential for normal oocyst development and sporozoite formation. Genome-wide RNA analysis of Δkinesin-8X parasites reveals modulated expression of genes involved in microtubule-based processes. Overall, the data suggest that Kinesin-8X is a molecular motor that plays essential roles during endomitosis in oocyst development in the mosquito, contributing to parasite transmission.

Lis1, the Drosophila homolog of a human lissencephaly disease gene, is required for germline cell division and oocyte differentiation

Development ◽  
1999 ◽  
Vol 126 (20) ◽  
pp. 4477-4488 ◽  
Author(s):  
Z. Liu ◽  
T. Xie ◽  
R. Steward
Keyword(s):  
Cell Division ◽  
Neuronal Migration ◽  
Nuclear Migration ◽  
Germline Cell ◽  
Causal Gene ◽  
Membrane Cytoskeleton ◽  
Drosophila Homolog ◽  
Congenital Brain Malformation ◽  
Development Analysis ◽  
Oocyte Differentiation

Lissencephaly is a severe congenital brain malformation resulting from incomplete neuronal migration. One causal gene, LIS1, is homologous to nudF, a gene required for nuclear migration in A. nidulans. We have characterized the Drosophila homolog of LIS1 (Lis1) and show that Lis1 is essential for fly development. Analysis of ovarian Lis1 mutant clones demonstrates that Lis1 is required in the germline for synchronized germline cell division, fusome integrity and oocyte differentiation. Abnormal packaging of the cysts was observed in Lis1 mutant clones. Our results indicate that LIS1 is important for cell division and differentiation and the function of the membrane cytoskeleton. They support the notion that LIS1 functions with the dynein complex to regulate nuclear migration or cell migration.

Asymmetric cell division and differentiation; fern spore germination as a model. II. Ultrastructural studies

1985 ◽  
Vol 86 ◽  
pp. 227-230
Author(s):  
Alix R. Bassel
Keyword(s):  
Cell Division ◽  
Metal Binding ◽  
Asymmetric Cell Division ◽  
Red Light ◽  
Nuclear Migration ◽  
Silver Stain ◽  
Metal Binding Sites ◽  
Ultrastructural Studies ◽  
Fern Spore Germination

SynopsisThe germination of Onoclea spores is a model system with many advantages for the study of asymmetric cell division and cellular differentiation. Our results suggest that both microtubules and a lipophilic site are important in the nuclear migration to one end of the spore prior to asymmetric cell division. A metalbinding region containing pore-like structures in the proximal face of the spore coat may be a source of the inherent polarity of the spore. The pattern of endogenous metal binding during germination has been characterised using a sulphide-silver stain. Metal-binding sites are described in a differentiating system in which polarity is imposed externally using polarised red light. The possibility of a role of ion gradients in determining the direction of nuclear migration is discussed.

scholarly journals A live-cell marker to visualize the dynamics of stable microtubules

2021 ◽  
Author(s):  
Klara I Jansen ◽  
Mithila Burute ◽  
Lukas C Kapitein
Keyword(s):  
Cell Division ◽  
Intracellular Transport ◽  
Living Cells ◽  
Live Cell ◽  
Organelle Transport ◽  
Cellular Organization ◽  
Cell Marker ◽  
Post Translational Modifications ◽  
And Function

The microtubule (MT) cytoskeleton underlies processes such as intracellular transport and cell division. Immunolabeling for post-translational modifications of tubulin has revealed the presence of different MT subsets, which are believed to differ in stability and function. Whereas dynamic MTs can readily be studied using live-cell plus-end markers, the dynamics of stable MTs have remained obscure due to a lack of tools to directly visualize these MTs in living cells. Here, we present a live-cell marker to visualize stable MTs and explore their dynamics. We demonstrate that a rigor mutant of kinesin-1 binds selectively to acetylated MTs without affecting MT organization and organelle transport. These MTs are long-lived, do not depolymerize upon nocadozale-treatment or laser-based severing, and display rich dynamics, including undulation, looping and sliding. This marker will help to explore how different MT subsets contribute to cellular organization and transport.

scholarly journals Not just a pretty cargo carrier: the other face of kinesins

2018 ◽  
Vol 40 (2) ◽  
pp. 22-25
Author(s):  
Claire Friel
Keyword(s):  
Cell Division ◽  
Large Family ◽  
The Other ◽  
Cellular Functions ◽  
Microtubule Motors ◽  
Kinesin Superfamily

If you've only ever heard of one kinesin, it's likely to be one that walks along microtubules and carries cargo around in the cell. However, this type of kinesin is only part of the kinesin story. The ‘kinesin superfamily’ is a large family of microtubule motors and members of the superfamily are critical to a variety of cellular functions. This article focuses on a class of kinesins that regulate the growth and shrinkage dynamics of microtubules. These kinesins orchestrate the construction and maintenance of microtubule structures required temporarily by cells, such as the apparatus that separates replicate chromosomes during cell division.

scholarly journals Assembly and regulation of γ-tubulin complexes

Open Biology ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 170266 ◽  
Author(s):  
Dorian Farache ◽  
Laurent Emorine ◽  
Laurence Haren ◽  
Andreas Merdes
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Intracellular Transport ◽  
Eukaryotic Cells ◽  
Cellular Structures ◽  
Activator Proteins ◽  
Multiprotein Complexes ◽  
Microtubule Organizing Centres ◽  
Different Types ◽  
Ring Complexes

Microtubules are major constituents of the cytoskeleton in all eukaryotic cells. They are essential for chromosome segregation during cell division, for directional intracellular transport and for building specialized cellular structures such as cilia or flagella. Their assembly has to be controlled spatially and temporally. For this, the cell uses multiprotein complexes containing γ-tubulin. γ-Tubulin has been found in two different types of complexes, γ-tubulin small complexes and γ-tubulin ring complexes. Binding to adaptors and activator proteins transforms these complexes into structural templates that drive the nucleation of new microtubules in a highly controlled manner. This review discusses recent advances on the mechanisms of assembly, recruitment and activation of γ-tubulin complexes at microtubule-organizing centres.

Atypical Rho GTPases RhoD and Rif integrate cytoskeletal dynamics and membrane trafficking

2014 ◽  
Vol 395 (5) ◽  
pp. 477-484 ◽  
Author(s):  
Pontus Aspenström
Keyword(s):  
Cell Migration ◽  
Cell Division ◽  
Membrane Trafficking ◽  
Rho Gtpases ◽  
Intracellular Transport ◽  
Cell Contraction ◽  
Cell Behaviour ◽  
Master Regulators ◽  
Cellular Processes ◽  
Cytoskeletal Dynamics

Abstract The Rho GTPases are essential regulators of basic cellular processes, including cell migration, cell contraction and cell division. Most studies still involve just the three canonical members, RhoA, Rac1 and Cdc42, although the Rho GTPases comprise at least 20 members. The aim of this review is to highlight some of the recent advances in our knowledge regarding the less-studied Rho members, with the focus on RhoD and Rif. The phenotypic alterations to cell behaviour that are triggered by RhoD and Rif suggest that they have unique impacts on cytoskeletal dynamics that distinguish them from the well-studied members of the Rho GTPases. In addition, RhoD has a role in the regulation of intracellular transport of vesicles. Taken together, the available data indicate that RhoD and Rif have functions as master regulators in the integration of cytoskeletal reorganisation and membrane trafficking.

scholarly journals Drosophila tubulin-binding cofactor B is required for microtubule network formation and for cell polarity

2012 ◽  
Vol 23 (18) ◽  
pp. 3591-3601 ◽  
Author(s):  
Alexandre D. Baffet ◽  
Béatrice Benoit ◽  
Jens Januschke ◽  
Jennifer Audo ◽  
Vanessa Gourhand ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Polarity ◽  
Intracellular Transport ◽  
Network Formation ◽  
Follicle Cells ◽  
Microtubule Network ◽  
Tubulin Binding ◽  
Associated Proteins ◽  
Dependent Cell

Microtubules (MTs) are essential for cell division, shape, intracellular transport, and polarity. MT stability is regulated by many factors, including MT-associated proteins and proteins controlling the amount of free tubulin heterodimers available for polymerization. Tubulin-binding cofactors are potential key regulators of free tubulin concentration, since they are required for α-β–tubulin dimerization in vitro. In this paper, we show that mutation of the Drosophila tubulin-binding cofactor B (dTBCB) affects the levels of both α- and β-tubulins and dramatically destabilizes the MT network in different fly tissues. However, we find that dTBCB is dispensable for the early MT-dependent steps of oogenesis, including cell division, and that dTBCB is not required for mitosis in several tissues. In striking contrast, the absence of dTBCB during later stages of oogenesis causes major defects in cell polarity. We show that dTBCB is required for the polarized localization of the axis-determining mRNAs within the oocyte and for the apico-basal polarity of the surrounding follicle cells. These results establish a developmental function for the dTBCB gene that is essential for viability and MT-dependent cell polarity, but not cell division.

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