Term | Value | Language |
---|---|---|
dc.contributor.advisor | Prehoda, Kenneth | |
dc.contributor.author | Holly, Ryan | |
dc.date.accessioned | 2020-09-24T17:08:45Z | |
dc.date.available | 2020-09-24T17:08:45Z | |
dc.date.issued | 2020-09-24 | |
dc.identifier.uri | https://scholarsbank.uoregon.edu/xmlui/handle/1794/25588 | |
dc.description.abstract | Animal cells polarize their membranes into discrete functional domains required for a host of cellular processes including asymmetric cell division, epithelial morphogenesis, neuronal polarization, and cell migration. A key regulator of animal cell polarity is the protein kinase, atypical Protein Kinase C (aPKC), whose activity is required for establishing and maintaining membrane polarity. While much is known about how the activity of aPKC polarizes cells, understanding the molecular mechanisms that lead to the regulation and localization of aPKC itself have remained controversial. aPKC’s apical localization depends on three additional proteins: Par-6, Par-3, and Cdc42. The focus of this work has been to understand the interplay between these proteins that lead to polarized aPKC. Par-3 is a regulatory substrate thought to directly target aPKC to the membrane. The first part of this work argues against a previously held view that Par-3 is an inhibitor of aPKC that is not phosphorylated until additional factors activate aPKC kinase activity. I clearly demonstrate that aPKC can indeed phosphorylate Par-3 without any additional inputs and that catalytic efficiency is similar to other known aPKC substrates. Furthermore, I argue that while Par-3 can indeed inhibit aPKC kinase activity, all substrates tested can inhibit kinase activity, questioning the physiological consequences of Par-3 inhibition of aPKC. The second part of this work aims to understand the physical interactions between Par-3 and the Par-complex, and how these interactions might contribute to the regulation of aPKC. At least 5 different interactions have been proposed between Par-3 and the Par-complex. Surprisingly, in vitro domain deletion analysis revealed that none of the previously proposed interactions are required for binding to the fully reconstituted Par-complex. However, through this analysis, I uncovered a novel interaction between the PDZ2 domain of Par-3 and a conserved aPKC PDZ ligand binding motif (PBM) that is required for the apical polarization of aPKC in the Drosophila neuroblast. Overall, the work presented in this dissertation significantly clarifies the controversial mechanisms surrounding the interactions between Par-3 and the Par-complex while defining a novel physical connection that links Par-3 to the Par-complex. This dissertation includes previously published co-authored material. | en_US |
dc.language.iso | en_US | |
dc.publisher | University of Oregon | |
dc.rights | All Rights Reserved. | |
dc.subject | aPKC | en_US |
dc.subject | Cell Polarity | en_US |
dc.subject | Par-3 | en_US |
dc.subject | Par-6 | en_US |
dc.title | Defining the Molecular Mechanisms that Govern Par-3 Mediated Polarization of the Par-Complex | |
dc.type | Electronic Thesis or Dissertation | |
thesis.degree.name | Ph.D. | |
thesis.degree.level | doctoral | |
thesis.degree.discipline | Department of Chemistry and Biochemistry | |
thesis.degree.grantor | University of Oregon |