My dissertation work was focused to characterize three members of the Kinesin superfamily in vitro. Kinesins are required in the cell for the correct localization and directed transport of proteins, DNA, RNA and cellular organelles. The three molecular motors of the kinesin superfamily studied here are Kar3Cik1, Kar3Vik1 and Nod. These three kinesins are unconventional in that they do not motor to the microtubule plus end transporting cargo over long distances, like Kinesin-1.
Kar3Cik1 and Kar3Vik1 are Saccharomyces cerevisiae Kinesin-14s, exhibiting minus end directionality characteristic of Kinesin-14s. Kar3Cik1 is essential for meiosis and for karyogamy, or mating in yeast. Kar3Cik1 also has non-essential roles in mitosis. Kar3Vik1 plays an important role at the spindle pole body during yeast mitosis. My work has shown that the two heterodimers interact with the microtubule in very different ways. Cik1 targets Kar3 to microtubule plus ends and enhances the Kar3-instrinsic depolymerizing ability. In contrast Vik1 binds the microtubule in addition to the Kar3 motor domain and depresses the Kar3 depolymerizing ability. Both of these functions correlate with the in vivo phenotypes and suggest different mechanisms of action for the two heterodimers.
Nod is a Drosophila melanogaster orphan kinesin proposed to provide a polar ejection force to stabilize chromosomes at the metaphase plate in meiosis. Our work characterized Nod as a kinesin that regulates microtubule dynamics by binding to the microtubule plus end and promoting microtubule polymerization. These results provide a mechanistic explanation for the polar ejection force observed in vivo.
My dissertation work has provided knowledge about the many ways in which different kinesins can interface with and regulate microtubule dynamics.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-12072006-155435 |
| Date | 26 January 2007 |
| Creators | Sproul, Lisa Raenae |
| Contributors | Claire Walczak, Paula Grabowski, John Rosenberger, Susan Gilbert, William Saunders |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-12072006-155435/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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