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Stability of protein complexes in the cytoskeleton of the eukaryotic flagellum
Pružincová, Martina ; Varga, Vladimír (advisor) ; Čajánek, Lukáš (referee)
The cilium/flagellum is a complex organelle protruding from the cell body and functioning in motility, sensing, and signalling. It is composed of hundreds of protein constituents, the majority of which comprise the flagellar cytoskeleton - the microtubule-based axoneme. Because the flagellum lacks ribosomes, its protein constituents have to be imported from the cell body and delivered to proper locations. Moreover, these proteins have to retain their function over a considerable length of time, despite the mechanical stress caused by flagellar beating and due to environmental exposure. This raises the question whether and where protein turnover occurs. Previously, it was established that Chlamydomonas reinhardtii flagella are dynamic structures (Marshall & Rosenbaum, 2001). In contrast, in the Trypanosoma brucei flagellum axonemal proteins are remarkably stable (Vincensini et al., 2018). However, the questions of axonemal assembly and stability were so far investigated only for a small number of proteins and during relatively short periods. Moreover, in these experiments expression of studied proteins was controlled by non-native regulatory elements. To elucidate the site of incorporation of proteins from all major axonemal complexes and to find out if and where the protein turnover occurs, T....
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Stability of protein complexes in the cytoskeleton of the eukaryotic flagellum
Pružincová, Martina ; Varga, Vladimír (advisor) ; Čajánek, Lukáš (referee)
The cilium/flagellum is a complex organelle protruding from the cell body and functioning in motility, sensing, and signalling. It is composed of hundreds of protein constituents, the majority of which comprise the flagellar cytoskeleton - the microtubule-based axoneme. Because the flagellum lacks ribosomes, its protein constituents have to be imported from the cell body and delivered to proper locations. Moreover, these proteins have to retain their function over a considerable length of time, despite the mechanical stress caused by flagellar beating and due to environmental exposure. This raises the question whether and where protein turnover occurs. Previously, it was established that Chlamydomonas reinhardtii flagella are dynamic structures (Marshall & Rosenbaum, 2001). In contrast, in the Trypanosoma brucei flagellum axonemal proteins are remarkably stable (Vincensini et al., 2018). However, the questions of axonemal assembly and stability were so far investigated only for a small number of proteins and during relatively short periods. Moreover, in these experiments expression of studied proteins was controlled by non-native regulatory elements. To elucidate the site of incorporation of proteins from all major axonemal complexes and to find out if and where the protein turnover occurs, T....
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Microtubule inner proteins
Bočan, Václav ; Libusová, Lenka (advisor) ; Sulimenko, Vadym (referee)
Microtubules are a prominent part of the cytoskeletal network in eukaryotic cells. They are involved in nearly all cellular processes, e.g. in vesicular trafficking, signal transduction, locomotion, or cell morphogenesis. To discharge that many functions, precise regulation of microtubule dynamics and architecture is essential. Such regulation is maintained by various microtubule-associated proteins, which usually bind from the outside. However, several proteins were found to bind in the lumen of microtubules. These microtubule inner proteins were shown to function either as post-translational modifiers of tubulin or stabilizers in time- persistent microtubular structures. A few inner proteins were identified, but our understanding of their attributes is still incomplete. This thesis summarizes current knowledge of microtubule inner proteins. The scope is focused on their enzymatic and structural features. Tubulin acetyltransferase represents the enzymatic MIPs. Possible ways of lumen entry and impact on the tubulin lattice are described. Next, the structural roles of proteins inside microtubules, most prominent in the axoneme, are outlined. The relevance of microtubule inner proteins for cytoskeletal functions, flagellar motility, and future perspectives are discussed at the end.
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