• MeSH
• buňky sekrece   MeSH
• cytoplazma MeSH
• fluorescenční mikroskopie MeSH
• Saccharomyces MeSH

Infection of non-enveloped polyomaviruses depends on an intact microtubular network. Here we focus on mouse polyomavirus (MPyV). We show that the dynamics of MPyV cytoplasmic transport reflects the characteristics of microtubular motor-driven transport with bi-directional saltatory movements. In cells treated with microtubule-disrupting agents, localization of MPyV was significantly perturbed, the virus was retained at the cell periphery, mostly within membrane structures resembling multicaveolar complexes, and at later times post-infection, only a fraction of the virus was found in Rab7-positive endosomes and multivesicular bodies. Inhibition of cytoplasmic dynein-based motility by overexpression of dynamitin affected perinuclear translocation of the virus, delivery of virions to the ER and substantially reduced the numbers of infected cells, while overexpression of dominant-negative form of kinesin-1 or kinesin-2 had no significant impact on virus localization and infectivity. We also found that transport along microtubules was important for MPyV-containing endosome sequential acquisition of Rab5, Rab7 and Rab11 GTPases. However, in contrast to dominant-negative mutant of Rab7 (T22N), overexpression of dominant-negative mutant Rab11 (S25N) did not affect the virus infectivity. Altogether, our study revealed that MPyV cytoplasmic trafficking leading to productive infection bypasses recycling endosomes, does not require the function of kinesin-1 and kinesin-2, but depends on functional dynein-mediated transport along microtubules for translocation of the virions from peripheral, often caveolin-positive compartments to late endosomes and ER - a prerequisite for efficient delivery of the viral genome to the nucleus.

• MeSH
• buněčné linie MeSH
• endocytóza * MeSH
• endoplazmatické retikulum metabolismus   virologie   MeSH
• endozomy metabolismus   virologie   MeSH
• mikrotubulární proteiny metabolismus   MeSH
• mikrotubuly metabolismus   MeSH
• molekulární motory metabolismus   MeSH
• myši MeSH
• Polyomavirus metabolismus   MeSH
• viabilita buněk MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Microtubules (MTs) are essential for many processes in plant cells. MT-associated proteins (MAPs) influence MT polymerization dynamics and enable them to perform their functions. The molecular chaperone Hsp90 has been shown to associate with MTs in animal and plant cells. However, the role of Hsp90-MT binding in plants has not yet been investigated. Here, we show that Hsp90 associates with cortical MTs in tobacco cells and decorates MTs in the phragmoplast. Further, we show that tobacco Hsp90_MT binds directly to polymerized MTs in vitro. The inhibition of Hsp90 by geldanamycin (GDA) severely impairs MT re-assembly after cold-induced de-polymerization. Our results indicate that the plant Hsp90 interaction with MTs plays a key role in cellular events, where MT re-organization is needed.

• MeSH
• benzochinony farmakologie   MeSH
• fylogeneze MeSH
• makrocyklické laktamy farmakologie   MeSH
• mikrotubuly účinky léků   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• polymerizace účinky léků   MeSH
• proteiny tepelného šoku HSP90 chemie   izolace a purifikace   metabolismus   MeSH
• rekombinantní proteiny izolace a purifikace   metabolismus   MeSH
• repetitivní sekvence aminokyselin MeSH
• rostlinné proteiny metabolismus   MeSH
• rýže (rod) účinky léků   metabolismus   MeSH
• sekvence aminokyselin MeSH
• tabák cytologie   účinky léků   metabolismus   MeSH
• transport proteinů účinky léků   MeSH
• tubulin metabolismus   MeSH
• vazba proteinů účinky léků   MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cell production and differentiation for the acquisition of specific functions are key features of living systems. The dynamic network of cellular microtubules provides the necessary platform to accommodate processes associated with the transition of cells through the individual phases of cytogenesis. Here, we show that the plant hormone cytokinin fine-tunes the activity of the microtubular cytoskeleton during cell differentiation and counteracts microtubular rearrangements driven by the hormone auxin. The endogenous upward gradient of cytokinin activity along the longitudinal growth axis in Arabidopsis thaliana roots correlates with robust rearrangements of the microtubule cytoskeleton in epidermal cells progressing from the proliferative to the differentiation stage. Controlled increases in cytokinin activity result in premature re-organization of the microtubule network from transversal to an oblique disposition in cells prior to their differentiation, whereas attenuated hormone perception delays cytoskeleton conversion into a configuration typical for differentiated cells. Intriguingly, cytokinin can interfere with microtubules also in animal cells, such as leukocytes, suggesting that a cytokinin-sensitive control pathway for the microtubular cytoskeleton may be at least partially conserved between plant and animal cells.

• MeSH
• Arabidopsis genetika   růst a vývoj   MeSH
• buněčná diferenciace * MeSH
• cytokininy genetika   metabolismus   MeSH
• kořeny rostlin genetika   růst a vývoj   MeSH
• mikrotubuly genetika   metabolismus   MeSH
• proliferace buněk * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: The presence of mitochondria is a distinguishing feature between prokaryotic and eukaryotic cells. It is currently accepted that the evolutionary origin of mitochondria coincided with the formation of eukaryotes and from that point control of mitochondrial inheritance was required. Yet, the way the mitochondrial presence has been maintained throughout the eukaryotic cell cycle remains a matter of study. Eukaryotes control mitochondrial inheritance mainly due to the presence of the genetic component; still only little is known about the segregation of mitochondria to daughter cells during cell division. Additionally, anaerobic eukaryotic microbes evolved a variety of genomeless mitochondria-related organelles (MROs), which could be theoretically assembled de novo, providing a distinct mechanistic basis for maintenance of stable mitochondrial numbers. Here, we approach this problem by studying the structure and inheritance of the protist Giardia intestinalis MROs known as mitosomes. RESULTS: We combined 2D stimulated emission depletion (STED) microscopy and focused ion beam scanning electron microscopy (FIB/SEM) to show that mitosomes exhibit internal segmentation and conserved asymmetric structure. From a total of about forty mitosomes, a small, privileged population is harnessed to the flagellar apparatus, and their life cycle is coordinated with the maturation cycle of G. intestinalis flagella. The orchestration of mitosomal inheritance with the flagellar maturation cycle is mediated by a microtubular connecting fiber, which physically links the privileged mitosomes to both axonemes of the oldest flagella pair and guarantees faithful segregation of the mitosomes into the daughter cells. CONCLUSION: Inheritance of privileged Giardia mitosomes is coupled to the flagellar maturation cycle. We propose that the flagellar system controls segregation of mitochondrial organelles also in other members of this supergroup (Metamonada) of eukaryotes and perhaps reflects the original strategy of early eukaryotic cells to maintain this key organelle before mitochondrial fusion-fission dynamics cycle as observed in Metazoa was established.

• MeSH
• databáze genetické MeSH
• Giardia lamblia * genetika   MeSH
• mitochondriální dynamika MeSH
• mitochondrie genetika   MeSH
• organely MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Stress-activated plant mitogen-activated protein (MAP) kinase pathways play roles in growth adaptation to the environment by modulating cell division through cytoskeletal regulation, but the mechanisms are poorly understood. We performed protein interaction and phosphorylation experiments with cytoskeletal proteins, mass spectrometric identification of MPK6 complexes and immunofluorescence analyses of the microtubular cytoskeleton of mitotic cells using wild-type, mpk6-2 mutant and plants overexpressing the MAP kinase-inactivating phosphatase, AP2C3. We showed that MPK6 interacted with γ-tubulin and co-sedimented with plant microtubules polymerized in vitro. It was the active form of MAP kinase that was enriched with microtubules and followed similar dynamics to γ-tubulin, moving from poles to midzone during the anaphase-to-telophase transition. We found a novel substrate for MPK6, the microtubule plus end protein, EB1c. The mpk6-2 mutant was sensitive to 3-nitro-l-tyrosine (NO2 -Tyr) treatment with respect to mitotic abnormalities, and root cells overexpressing AP2C3 showed defects in chromosome segregation and spindle orientation. Our data suggest that the active form of MAP kinase interacts with γ-tubulin on specific subsets of mitotic microtubules during late mitosis. MPK6 phosphorylates EB1c, but not EB1a, and has a role in maintaining regular planes of cell division under stress conditions.

• MeSH
• anafáze účinky léků   MeSH
• aparát dělícího vřeténka účinky léků   metabolismus   MeSH
• Arabidopsis cytologie   účinky léků   enzymologie   MeSH
• butadieny farmakologie   MeSH
• cytokineze účinky léků   MeSH
• extracelulárním signálem regulované MAP kinasy metabolismus   MeSH
• fosforylace účinky léků   MeSH
• fyziologický stres * účinky léků   MeSH
• kinetochory účinky léků   metabolismus   MeSH
• meristém cytologie   účinky léků   metabolismus   MeSH
• mikrotubuly účinky léků   metabolismus   MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• nitrily farmakologie   MeSH
• nitrosace účinky léků   MeSH
• proliferace buněk účinky léků   MeSH
• proteiny asociované s mikrotubuly metabolismus   MeSH
• proteiny huseníčku metabolismus   MeSH
• rostlinné buňky účinky léků   metabolismus   MeSH
• segregace chromozomů účinky léků   MeSH
• telofáze účinky léků   MeSH
• tubulin metabolismus   MeSH
• tyrosin analogy a deriváty   farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Highly conserved α- and β-tubulin heterodimers assemble into dynamic microtubules and perform multiple important cellular functions such as structural support, pathway for transport and force generation in cell division. Tubulin exists in different forms of isotypes expressed by specific genes with spatially- and temporally-regulated expression levels. Some tubulin isotypes are differentially expressed in normal and neoplastic cells, providing a basis for cancer chemotherapy drug development. Moreover, specific tubulin isotypes are overexpressed and localized in the nuclei of cancer cells and/or show bioenergetic functions through the regulation of the permeability of mitochondrial ion channels. It has also become clear that tubulin isotypes are involved in multiple cellular functions without being incorporated into microtubule structures. Understanding the mutations of tubulin isotypes specifically expressed in tumors and their post-translational modifications might help to identify precise molecular targets for the design of novel anti-microtubular drugs. Knowledge of tubulin mutations present in tubulinopathies brings into focus cellular functions of tubulin in brain pathologies such as Alzheimer's disease. Uncovering signaling pathways which affect tubulin functions during antigen-mediated activation of mast cells presents a major challenge in developing new strategies for the treatment of inflammatory and allergic diseases. γ-tubulin, a conserved member of the eukaryotic tubulin superfamily specialized for microtubule nucleation is a target of cell cycle and stress signaling. Besides its microtubule nucleation role, γ-tubulin functions in nuclear and cell cycle related processes. This special issue "Tubulin: Structure, Functions and Roles in Disease" contains eight articles, five of which are original research papers and three are review papers that cover diverse areas of tubulin biology and functions under normal and pathological conditions.

• MeSH
• Alzheimerova nemoc genetika   metabolismus   patologie   MeSH
• lidé MeSH
• mikrotubuly genetika   metabolismus   patologie   MeSH
• mutace MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• nádory genetika   metabolismus   MeSH
• protein - isoformy MeSH
• tubulin genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• úvodní články MeSH
• úvodníky MeSH

• MeSH
• entomologie MeSH
• fyziologie buňky MeSH
• hematologie MeSH
• kompartmentace buňky MeSH
• nádorové procesy MeSH
• Publikační typ
• kongresy MeSH

• Konspekt
• Biologické vědy
• NLK Obory
• biologie
• biologie
• onkologie