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Mammalian septins in cellular processes
Hrbáč, Patrik ; Libusová, Lenka (advisor) ; Zelená, Marie (referee)
Septins are cytoskeletal GTP-binding proteins with unique properties that can be found in species ranging from single-cell eukaryotes to mammals with the exclsuion of vascular plants. Septins are well conserved across species in both their structure and function. They are located in the cytoplasm, where they can assemble into filaments and higher order structures. Moreover, septins can interact with membranes, actin filaments, microtubules, and various proteins. Changes in septin expression often result in numerous defects in cellular processes and are, therefore, linked to a multitude of diseases. For that reason, mammalian septins appear to be of clinical importance. With the ever-increasing number of discovered cellular roles, septins are becoming a point of interest for many and the amount of information known about them grows rapidly. In this review, I attempt to summarise knowledge about the structure, assembly and function of mammalian septins, as well as their possible practical use.
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Functional study of the SUF pathway in the cell of Monocercomonoides exilis and Paratrimastix pyriformis
Zelená, Marie ; Hampl, Vladimír (advisor) ; Verner, Zdeněk (referee)
The synthesis of iron-sulfur clusters is an essential cellular process, which depends on complex biosynthetic pathways. In model eukaryotes, these pathways are the ISC pathway in the mitochondria and the CIA pathway in the cytosol. A recent genome and transcriptome analysis showed, that an amitochondriate protist Monocercomonoides exilis lacks the canonical ISC pathway, which has been replaced by a bacterial SUF pathway. A close free-living relative of M. exilis, Paratrimastix pyriformis possesses a mitochondrion-related organelle, yet also possesses a SUF pathway instead of ISC. The acquisition of the SUF pathway has been suggested as the primordial cause for mitochondrial loss in M. exilis, which is the first documented eukaryotic organism without a mitochondrion. The SUF pathway has been the subject of numerous studies in bacteria, however, its role as the core provider of iron-sulfur clusters for eukaryotic cells has been reported in merely a handful of eukaryotes and was based predominantly on genomic data. This thesis focuses on the putative ATPase SufC and the putative scaffold protein SufB. Both proteins were successfully produced in recombinant forms. SufC has been found to possess ATPase activity in vitro, which was increased upon interaction with SufB. The conditions for theATPase...
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Iron-sulphur cluster synthesis in anaerobic protists
Zelená, Marie ; Hampl, Vladimír (advisor) ; Mach, Jan (referee)
Iron-sulpur clusters are small ubiquitous cofactors of proteins present in all cells. These proteins participate in many important processes such as gene expression or respiratory chain. In vivo synthesis of iron-sulphur clusters requires complex biosynthetic pathways. In eukaryotic cells these pathways are localized inside mitochondria and plastids and in the cytosol. Cytosolic synthesis depends on a product of the mitochondrial pathway. Mitochondria of anaerobic protists in most cases went through reductive evolution, which is associated with the reduction of mitochondrial iron-sulphur cluster biosynthetic pathway. In many cases, these organisms acquired alternative pathways via lateral gene transfer, which act either as a complement to the mitochondrial pathway, or as its complete functional substitution. Replacement of the mitochondrial pathway might have been a key event for secondary loss of mitochondria. Key words: Iron-sulphur clusters, anaerobic protists, ISC, CIA, SUF, mitochondrion
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