OmiHtrA2 is a highly conserved mammalian serine protease that belongs to the HtrA family of proteins. Omi shares homology with the bacterially expressed heat shock protease HtrA, which functions as a protease at higher temperatures and a chaperone at lower temperatures. Additionally, Omi shares sequence similarity with the mammalian homologs L56/HtrA1 and PRSP/HtrA3. Omi was first isolated as an interacting protein of Mxi2, an alternatively spliced form of the p38 stress-activated kinase, using a modified yeast two-hybrid system. Omi localizes in the mitochondria and in response to apoptotic stimuli the mature form of this protein translocates to the cytoplasm. In the cytoplasm Omi participates in both the caspase-dependent as well as caspase-independent apoptosis. Additionally, recent studies suggest that Omi may have another unique function, maintaining homeostasis within the mitochondria. In an effort to further elucidate the function of Omi, a yeast two-hybrid screening was performed to isolate novel interacting proteins. This screening identified a novel protein (HOPS), as a specific interactor of Omi. The predicted amino acid sequence of this protein does not provide any information about its potential function in mammalian cells. However, experiments show that HOPS is cleaved in vitro by Omi. Furthermore, in response to apoptotic stimuli, HOPS is also degraded in vivo. This study suggests that HOPS could be a physiological substrate of Omi that is cleaved and removed during apoptosis.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd-1244 |
| Date | 01 January 2004 |
| Creators | Stratico, Valerie Anne |
| 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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