Transport of intracellular cargo is an important and dynamic process required for cell maintenance and survival. Dynein is the motor protein that carries organelles and vesicles from the cell periphery to the cell center along the microtubule network. Dynactin is a protein that activates dynein for this transport process. Together, dynein and dynactin forms a motor protein complex that is essential for transport processes in all the vertebrate cells. Using fluorescent microscope based live cell imaging techniques and kymograph analyses, I studied dynein/dynactin disruptions on the intracellular transport in two different cell systems. In one set of experiments, effects of dynein heavy chain (DHC) mutations on the vesicular motility were characterized in the fungus model system Neurospora crassa. I found that many DHC mutations had a severe transport defect, while one mutation linked to neurodegeneration in mice had a subtle effect on intracellular transport of vesicles. In a different set of experiments in mammalian tissue culture CAD cells, I studied the effects of dynactin knockdown and dynein inhibition on mitochondrial motility. My results indicated that reductions in dynactin levels decrease the average number of mitochondrial movements and surprisingly, increase the mitochondrial run lengths. Also, I determined that the dynein inhibitory drug Ciliobrevin causes changes in mitochondrial morphology and decreases the number of mitochondrial movements inside cells. Overall, my research shows that distinct disruptions in the dynein and dynactin motor complex alters intracellular motility, but in different ways. So far, my studies have set the ground work for future experiments to analyze the motility mechanism of motor proteins having mutations that lead to neurodegenerative disorders.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd-3845 |
| Date | 01 January 2013 |
| Creators | Nandini, Swaran |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations |
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