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Dissertation
Characterizing the APC/C-AMA1-substrate complex and its role in regulating meiotic progression
Doctor of Philosophy (Ph.D.), Drexel University
Aug 2005
DOI:
https://doi.org/10.17918/00009595
Abstract
The anaphase promoting complex/cyclosome (APC/C) is one of two main multi-subunit ubiquitin ligase (E3) complexes involved in the ubiquitylation pathway during mitosis and meiosis. By targeting the degradation of key proteins, the cell ensures its irreversible progression through mitosis and meiosis. The focus of this thesis is on Ama1p, a meiosis-specific activator of the APC/C, which acts to recruit specific meiotic proteins to the E3 ligase for ubiquitylation and subsequent degradation. To understand how the APC/C works during meiosis, we undertook analysis as to how Ama1p recognizes both the APC/C and its substrates. The known determinants for APC/C binding were not essential for Ama1p to bind to the E3 ligase complex, but were required for APC/CAmal activity. In addition, the amino terminus contains an uncharacterized region that is required for APC/C binding, but not activation, suggesting a model in which binding of Ama1p to APC/C is uncoupled from APC/C activation. Substrate specificity is also determined by the highly divergent amino-terminus of Ama1p. However, analysis of a chimeric Ama1/Hct1 protein revealed that the N-terminus region can only partially activate the APC/C, suggesting the amino terminus is sufficient for the downregulation of substrates during meiosis; however the C-terminal domain is important for other Ama1p functions. Studies with Cdc20p as a substrate of APC/CAmal reveals that its D1 destruction box motif is important for its own downregulation during meiosis, but other novel uncharacterized degradation determinants may be involved. Gaining knowledge about assembly of the APC/C-Amal-substrate complex and the mechanisms involved in regulating its temporal activities will lead to invaluable insights of how the cell controls meiotic progression.
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Details
- Title
- Characterizing the APC/C-AMA1-substrate complex and its role in regulating meiotic progression
- Creators
- Grace Sim Yuen Tan
- Contributors
- Katrina F. Cooper (Advisor) - Drexel University, Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xi, 110, [20] pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Biochemistry and Molecular Biology; College of Medicine; Drexel University
- Other Identifier
- 991021888954604721