Tunelske membranske nanocevke (TnT, angl. Tunneling nanotubes) omogočajo medcelično komunikacijo med evkariontskimi celicami in tudi med bakterijami. TnT so cevasti izrastki, ki povezujejo celice in omogočajo izmenjavo organelov, veziklov in citoplazemskih molekul. V nalogi smo raziskali prisotnost in lokacijo motornih proteinov kinezina 5B, dineina in miozina Va v TnT normalnih urotelijskih celic (NPU) in rakavih urotelijskih celic (T24). Nastanek in morfologijo TnT smo spremljali s korelativno faznokontrastno-fluorescenčno mikroskopijo. Z metodo prenosa western smo preverjali prisotnost motornih proteinov v celicah NPU in T24, z metodo imunooznačevanja pa njihovo lokacijo v TnT. Dokazali smo, da so izbrani motorni proteini prisotni v TnT celic NPU in T24 in da njihova prisotnost sovpada s prisotnostjo pripadajočih citoskeletnih elementov. Pokazali smo, da se TnT celic NPU in T24 razlikujejo v vsebnosti motornih proteinov in smeri aktivnega transporta, ter da lahko znotraj iste TnT sočasno obstaja več mehanizmov aktivnega transporta. Celice NPU in T24 smo gojili tudi v kokulturi in dokazali, da so motorni proteini prisotni tudi v TnT med normalnimi in rakavimi celicami. Pregled literature je pokazal, da bakterijske TnT nastajajo med bakterijami iste ali različnih vrst in da imajo ključno vlogo pri nastanku in vzdrževanju večceličnih bakterijskih združb in biofilmov. Mehanizmi transporta po bakterijskih TnT so še slabo raziskani. Z magistrsko nalogo smo prispevali nova spoznanja o mehanizmih medcelične komunikacije s TnT, ki bodo, skupaj z nadaljnimi raziskavami, pripomogla k razvoju novih načinov zdravljenja rakavih in infekcijskih obolenj. 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.