Mitotic motors have gained considerable interest as anticancer targets given their often essential functions during mitosis. Furthermore, mitotic motors are thought to represent ideal targets because their functions are believed to be confined to mitosis; thus, only rapidly dividing cells would be susceptible to inhibitors of mitotic motors. The work presented herein challenges the concept of mitotic motors as specific targets of dividing cells by exploring the interphase function of three mitotic motors Kid, Eg5, and MKLP1. Our results demonstrate that all three motors associate with the nucleolus and with the ribosomal subunits. Furthermore, it is demonstrated Eg5 functions to increase the processivity of the ribosome, the first cellular factor to be characterized with that property. Additionally, as loss of Kid results in an increase in focal adhesion proteins throughout the cell and increased protein synthesis in its absence, our data are consistent with a role for Kid in mRNA silencing and transport of mRNAs for site-specific translation. Also, evidence is presented that suggests a role for Kid in ribosome biogenesis and/or ribosomal function, similar to nucleophosmin. Finally, both Kid and Eg5 participate in stress granule dynamics, with Kid and Eg5 functioning in stress granule formation, and Eg5 participating in stress granule coalescence, transport and dissolution. Collectively these findings demonstrate diverse interphase functions for these mitotic motors in nearly all phases of the ribosomes life cycle. These studies not only call into question the potential safety of mitotic motor inhibitors for the treatment of cancer, but also open a new avenue of exploring polypeptide synthesis.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-12072010-180919 |
| Date | 09 December 2010 |
| Creators | Bartoli, Kristen Marie |
| Contributors | Laura J. Niedernhofer, M.D., Ph.D., Saleem A. Khan, Ph.D., William S. Saunders, Ph.D., John L. Woolford, Jr. Ph.D, Stefan Duensing, M.D. |
| 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-12072010-180919/ |
| 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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