Tunneling membrane nanotubes (Tunneling nanotubes,TnTs) are one of the mechanisms of intercellular communication between eukariotic cells and between bacteria. TnTs are tubular protrusions that connect cells and facilitate active transport of organelles, vesicles and cytoplasmic moleculs between cells. In this thesis we studied the presence and location of three selected motor proteins: kinesin 5B, dynein and myosin Va in TnTs of normal urothelial cells (NPU) and cancer urothelial cells (T24). We used a method of correlative phase-contrast and fluorescent microscopy to study the development and morphology of TnTs. We used western blot to show that NPU and T24 cells contain different motor proteins, and determined their location in TnT with immunofluorescence. We proved that TnTs contain different motor proteins and that their presence correlates with the presence of appropriate cytoskeletal elements. We found out that TnTs of NPU and T24 cells differ in the content of motor proteins and direction of active transport. We also showed that different mechanisms of active transport can coexist inside one TnT. We cultured normal urothelial cells and cancer urothelial cells in coculture and proved that there are motor proteins present also in TnT between normal and cancer urothelial cells. The examination of the literature on bacterial TnTs showed that TnTs connect bacteria of the same and different species and that TnTs are crucial in development and maintainance of multicellular bacterial communities and biofilms. Mechanisms of transport in bacterial TnTs are still unknown. This master thesis provides new insights into the mechanisms of intercellular communication with TnTs that will in the future, together with further research, importantly contribute to the development of new approaches for treating cancerous and infectious diseases.
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