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Significantion of sumoylation for infection by selected viruses replicated in the cell nucleus
Sejpková, Marie ; Forstová, Jitka (advisor) ; Frydrýšková, Klára (referee)
This work introduces association between viruses and host cell with respect to sumoylation process. The main aim is referring to influence of this modification both on virus replication strategy and cell cycle. Sumoylation is essential process for cell regulation interfering with general regulation pathways including those performed by e.g. p53 or PML bodies and also epigenetic changes of chromatin. For viruses, sumoylation means stabilization of viral proteins and better timing each phase of viral cycle through viral protein. One point of view is competition of cell and virus for SUMO machinery. Viruses take advantage of sumoylation for inhibition antiviral defense of cells, regulation cell cycle mainly in apoptosis induction and in general for more successful infection. There are cumulating evidence of new proteins and phenomena connected with sumoylation mechanisms as well as viruses exploiting sumoylation for their benefit. Utilization and abuse of sumoylation by viruses point to future possibilities of cell manipulation and virus ability to intervene to this still relatively poorly understood type of cell regulation.
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The role of the Smc5/6 complex in DNA viral infection
Protivová, Eliška ; Huerfano Meneses, Sandra (advisor) ; Pokorná, Karolína (referee)
The Smc5/6 complex is an eukaryotic protein complex that, together with Smc1/3 cohesin and Smc2/4 condensin, is involved in ensuring genome stability. It contributes to this by participating in the organization and maintenance of chromosomal structures as well as in the response to DNA damage. In addition, the Smc5/6 complex has been shown to play an important role in viral infection. This thesis focuses on the mechanisms of interaction of the Smc5/6 complex with viral DNA genomes, DNA intermediate genomes and viral proteins. In the case of HBV of the Hepadnaviridae family, Smc5/6 acts as a restriction factor. The same is true for HSV-1 of the Herpesviridae family, viruses of the Papillomaviridae family and HIV-1 of the Retroviridae family. An interaction of the Smc5/6 complex with the JC virus of the Polyomaviridae family has also been discovered. Nevertheless, the meaning of this interaction remains elusive. Some of the above-mentioned viruses can prevent this restriction. In detail, HBx protein of HBV mediates proteasomal degradation of the Smc5/6 complex or Vpr protein of HIV-1 induces degradation of the SLF2 protein, which is responsible for the Smc5/6 localization on HIV-1 DNA intermediate genomes. Keywords: Smc5/6 complex, DNA repair, ATPase, sumoylation, DNA viruses, viruses with a DNA...
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Study of the posttrans lation al modifications of phosducin
Šimůnek, Jiří ; Obšil, Tomáš (advisor) ; Alblová, Miroslava (referee)
The aim of this diploma thesis was to study the role of posttranslational modifications of phosducin and their role in the interaction with the 14-3-3 protein as well as the influence of the complex formation on these modifications. Phosducin is a 33kDa protein commonly present in photoreceptor cells of the retina as well as other tissues. Despite many experiments, its physiological functions are still elusive. It has been speculated that fosducin plays an important regulatory role in visual phototransduction pathway, regulation of blood pressure and expression of G-proteins. The phosducin function is regulated through binding to the 14-3-3 protein, a regulatory protein involved in many biochemical processes. Phosducins binding to 14-3-3 protein requires phosphorylation of two serine residues Ser-54 and Ser-73 within the N-terminal domain of phosducin. However, the role of the 14-3-3 protein binding in the regulation of phosducin function is still unclear. In this diploma thesis proteins 14-3-3ζ∆C and phosducin (mutation Q52K) were successfully expressed and purified. The effect of the complex formation on phosducin posttranslational modifications was investigated using limited proteolysis and dephosphorylation. These experiments revealed that the complex formation significantly slowed down both...
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Significantion of sumoylation for infection by selected viruses replicated in the cell nucleus
Sejpková, Marie ; Forstová, Jitka (advisor) ; Frydrýšková, Klára (referee)
This work introduces association between viruses and host cell with respect to sumoylation process. The main aim is referring to influence of this modification both on virus replication strategy and cell cycle. Sumoylation is essential process for cell regulation interfering with general regulation pathways including those performed by e.g. p53 or PML bodies and also epigenetic changes of chromatin. For viruses, sumoylation means stabilization of viral proteins and better timing each phase of viral cycle through viral protein. One point of view is competition of cell and virus for SUMO machinery. Viruses take advantage of sumoylation for inhibition antiviral defense of cells, regulation cell cycle mainly in apoptosis induction and in general for more successful infection. There are cumulating evidence of new proteins and phenomena connected with sumoylation mechanisms as well as viruses exploiting sumoylation for their benefit. Utilization and abuse of sumoylation by viruses point to future possibilities of cell manipulation and virus ability to intervene to this still relatively poorly understood type of cell regulation.
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