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Three Unconventional Kinesins Exhibit Novel Microtubule Interactions:The Characterization of Kar3Cik1, Kar3Vik1, and Nod

Sproul, Lisa Raenae (2007) Three Unconventional Kinesins Exhibit Novel Microtubule Interactions:The Characterization of Kar3Cik1, Kar3Vik1, and Nod. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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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.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Sproul, Lisa
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairGilbert, Susanspg1@pitt.eduSPG1
Committee MemberWalczak, Claire
Committee MemberRosenberger,
Committee MemberGrabowski, Paulapag4@pitt.eduPAG4
Committee MemberSaunders, Williamwsaund@pitt.eduWSAUND
Date: 26 January 2007
Date Type: Completion
Defense Date: 31 August 2006
Approval Date: 26 January 2007
Submission Date: 7 December 2006
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Biological Sciences
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: cik1; drosophila; kar3; kinesin; microtubules; molecular motors; nod; vik1; yeast
Other ID:, etd-12072006-155435
Date Deposited: 10 Nov 2011 20:08
Last Modified: 15 Nov 2016 13:53


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