National Repository of Grey Literature 25 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The role of anillin in the growth cone of neurons
Tomášová, Štěpánka ; Libusová, Lenka (advisor) ; Vinopal, Stanislav (referee)
During embryonal development, axons of newly differentiated neurons need to properly interconnect and create a functional neuronal network. To achieve this, the cell requires a growth cone. The growth cone is a highly dynamic structure at the end of growing axons that serves both as the navigator and the propeller. Crosstalk between actin and microtubules is vital for proper axonal pathfinding. But the exact mechanism of this cooperation remains unknown. This diploma thesis investigates the possible role of a candidate scaffolding protein called anillin in this process. Anillin has been studied in two human cell lines. SH-SY5Y neuroblastoma cell line was used for overexpression and siRNA knock-down experiments. Anillin overexpression led to perturbed neurite morphology and growth cone dynamics in SH-SY5Y cells, whereas cells with lower anillin expression had fewer neurites. Next, neurons differentiated from human iPSC (induced pluripotent stem cells) expressing endogenous fluorescently tagged anillin were studied. Local dynamic high concentration spots of anillin have been observed at the base of cell protrusions of differentiating neurons. These anillin flares appeared during cell migration, early neurite initiation, and in newly created growth cones. These results suggest that anillin plays a...
Actin and the ARP 2/3 complex in the nucleus
Němcová, Barbora ; Bellinvia, Erica (advisor) ; Hála, Michal (referee)
The eukaryotic actin cytoskeleton is required for numerous cellular processes, including cell shape, development and movement, gene expression and signal transduction, and response to biotic and abiotic stress. Actin constitutes a wide family of proteins that are major components of the cytoskeleton. Actin is one of the most abundant proteins in living organisms. Actin has essential functions both in the cytoplasm and in the nucleus, where it has been linked to key nuclear processes. Recent studies have shown that actin is actively transported from the cytoplasm to the nucleus, where it regulates transcriptional aktivity, regulates RNA polymerases, is involved in chromatin remodeling and repair damaged DNA. The presence of typical actin filaments in the nucleus has not been demonstrated directly.but nuclear actin occurs in many forms such as actin rods, short actin polymers, actin monomers, or actin complexes with profilin or cofilin. Most eukaryotic cells also contain at least eleven actin-related proteins (ARPs). Although many ARPs are cytoskeletal, recent biochemical and genetic work has demonstrated that some ARPs function largely or entirely in the nucleus. Nuclear ARPs are recognized as novel key regulators of genome function, and affect not only the remodeling of chromatin but also the...
Cytoskeleton-membrane protein interaction network in sperm
Adamová, Zuzana ; Komrsková, Kateřina (advisor) ; Tolde, Ondřej (referee)
In order to fertilize the egg, sperm cell undergoes several subsequent maturation processes. The final one called acrosome reaction is an exocytosis of acrosome vesicle, which is filled with lytic enzymes. Acrosome reaction is crucial for penetration of the sperm cell through the egg surroundings, especially zona pellucida, as well as for reorganization of a membrane protein composition on its surface. This rearrangement leads to the exposure of proteins essential for fertilization, mainly for gamete recognition, binding and fusion in specific compartments of the sperm head. One of such protein is CD46, which is located in the acrosomal membrane of an intact sperm and after acosomal exocytosis it relocates to the equatorial segment of a sperm head, which is known to be the initial site of interaction of sperm with the egg plasma membrane. The relocation of CD46 is disrupted by inhibition of actin, which reorganization within sperm head is known to play a role in onset of acrosome reaction, however, the precise mechanism of CD46 interaction with actin in sperm is unknown. In this thesis, ezrin - a crosslinker of membrane proteins and actin - has been studied in context of CD46 and its relocation across the sperm head. Analysis of the immunofluorescent detection of ezrin revealed its mutual...
Interakce viru klíšťové encefalitidy s cytoskeletem hostitelských buněk
This thesis is focused on the role of host cytoskeleton, primarily microtubules and microfilaments, during tick-borne encephalitis virus infection in human neuroblastoma cell line SK-N-SH and tick cell line IRE/CTVM19. The importance of cytoskeletal integrity and dynamics to the viral replication cycle were examined using specific chemical inhibitors showing the virus utilizes studied structures in both cell lines. Immunofluorescence microscopy revealed structural changes in the actin cytoskeleton during late infection in SK-N-SH cells. Moreover, differences in expression of cytoskeleton-associated genes in both cell lines were compared. Several genes with up-regulated expression in SK-N-SH cells were identified during late infection.
Characterization of WASH complex member protein SWIP
Humhalová, Tereza ; Libusová, Lenka (advisor) ; Lánský, Zdeněk (referee)
WASH complex regulates actin dynamics on endosomes by activating the Arp2/3 complex, which subsequently induces generation of branched actin patches. WASH complex is required for proper recycling of many important transmembrane proteins. Although the general physiological function of WASH complex is known, the role of its single subunits have not yet been adequately specified. This work focuses on one of these subunits - protein SWIP. This protein maintains vesicular localization of some WASH complex subunits in the slime mold Dictyostelium discoideum and a point mutation in its sequence causes a severe neurodegenerative disease - autosomal recessive intellectual disorder (ARID). Our results show that SWIP truncation results in its inability to incorporate into WASH complex. However, the C-terminal part of SWIP is able to localize onto intracellular vesicles, which are not WASH complex positive. We have also studied the impact of ARID-causing SWIP mutation, and we show, that it does neither change the protein's ability to bind the complex nor the overall localization of WASH complex.
The role of cytoskeleton in endosomal fusion and fission
Získalová, Tereza ; Libusová, Lenka (advisor) ; Tolde, Ondřej (referee)
Cytoskeleton plays a key role in endocytic process. Vesicules move along microtubules to target membranes. Microtubules also partake in the formation of endosomal tubules, from which recyclated vesicules are splitted off. Actin network has in endocytosis multi-ple effect as well. In the case of membrane fusion is its role both, positive and negative, for it creates mechanical force which facilitates the fusion in last stage. By contrast, in the first stage, it acts as a physical barrier, which needs to be removed. Actin also actively participates in fission of vesicules. Actin network and microtubules are thus interconnected with endocytic pathway in time and space. Right functional connection of the cytoskeleton with dynamics of endocytic vesicles is driven by many regulatory proteins. Among important regulators of actin network belong for example proteins of Arp2/3, WASH complex, WASP or Rab and Rho proteins. Powered by TCPDF (
Role of translational elongation factors in dynamics of stress granules.
Hlaváček, Adam ; Hašek, Jiří (advisor) ; Janderová, Blanka (referee)
eIF5A seems to be involved in both, translation initiation and elongation. It was also reported to affect assembly of P-bodies. Given similarities of P-bodies with stress granules (SGs) we decided to test the role of eIF5A in dynamics of heat-induced SGs and its implications for the cell recovery. For the evaluation of eIF5A function in SGs formation was used the temperature- sensitive (ts) mutant eIF5A-3 (C39Y/G118D) cultivated under permissive temperature 25řC and Rpg1-GFP fusion protein as a marker of SGs. The cells were exposed to robust heat shock at 46řC for 10 minutes. The ability of the mutant cells to recover was tested by propidium iodine staining and colony forming units plating. We found that the eIF5A-3 mutant forms heat-induced SGs more loosely aggregated, indicating that the fully functional eIF5A is necessary for SGs assembly. However, it does not seem to affect the rate of SGs dissolution. Survival tests indicate that eIF5A-3 mutant cells are susceptible to dying in a similar way as WT cells; nevertheless, their ability to resume proliferation is significantly better. We also observed a loss of the ts phenotype of the eIF5A-3 mutant. This loss cannot be explained by reversion of mutated eIF5A sequence into normal. Probable cause lies in the adaptive evolution. Our results indicate role of...
Invasive structures of cancer cells in 3D environment
Lyková, Dominika ; Tolde, Ondřej (advisor) ; Libusová, Lenka (referee)
The ability of cells to migrate through tissue barriers plays an important role in physiological and pathological processes including immune response or invasiveness of cancer cells. The cells generate cytoplasmic protrusions called podosomes and invadopodia, collectively known as invadosomes or podosome-type adhesions (PTA), which are thought to be the key structures of cell invasion, especially of cancer cells during metastasis. Invadosomes are F-actin rich cell-matrix contacts with capability to degrade extracellular matrix components and are observed both in normal cells (such as monocytic cells, endothelial cells and smooth muscle cells) and in cancer cells. This bachelor thesis is focused on those in cancer cells, their initiation, regulation, function and morphology in 3D and in vivo and their requirement for tumor metastasis.
Molecular mechanisms of cell polarity and morphogenesis in moss Physcomitrella patens
D'Agostino, Viktoria ; Žárský, Viktor (advisor) ; Soukup, Aleš (referee)
Plant cells are able to establish polarity and expand by tip growth. Polarized cells often embrace functions important for plant viability. The process of tip growth requires actin cytoskeleton in collaboration with a number of accessory proteins. The position of the intensively expanding region is provided by microtubules and the function of signalling proteins. Polarized secretion regulates the structural properties and subsequently the shape of the cell wall. Some components of the secretory and signalling pathways are highly conserved among eukaryotes, others are found exclusively in the plant kingdom. Though much has been discovered in yeast and animal cells, many mechanisms in plants are yet to be revealed. Model systems performing tip growth, such as root hairs, pollen tubes and protonema cells, enable comparison and thus a complementary overview of the various processes.
Interplay of cytoskeleton and secretory pathway during exocytosis in plant cells
Aldorfová, Klára ; Sekereš, Juraj (advisor) ; Vosolsobě, Stanislav (referee)
Cytoskeleton is known to participate in exocytosis of yeast and animal cells. The role of plant cytoskeleton during exocytosis has not been fully understood yet. However, both actin and microtubules evidently contributes to the secretion of specific cargo proteins or cell wall components. Plant cytoskeleton influences the dynamics of exocytosis through various functions. First, secretory vesicles are delivered near the plasma membrane. Second, microtubules were shown to mark the place of exocytosis. Third, cytoskeleton is able to prevent membrane fusion by simple separation of compartments. Fourth, cytoskeleton potentially mediates the interaction between molecules of secretory apparatus. Secretion of certain cargo molecules appears to be dependent on different cytoskeleton types and the exocytosis seems to be specifically regulated in each tissue. This thesis aims to describe interplay of cytoskeleton and secretory pathway on the example of tip growth and to predict future direction of research on secretory pathway based on cellulose synthase secretory data.

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