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You searched for +publisher:"University of Nevada – Las Vegas" +contributor:("Nora Caberoy"). Showing records 1 – 3 of 3 total matches.

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University of Nevada – Las Vegas

1. Ibarra, Rebeca Lea. The San1 Ubiquitin Ligase Functions Preferentially with Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control.

Degree: MS, Chemistry and Biochemistry, 2016, University of Nevada – Las Vegas

Protein quality control (PQC) is a critical process wherein misfolded or damaged proteins are cleared from the cell to maintain protein homeostasis. In eukaryotic cells, the removal of misfolded proteins is primarily accomplished by the ubiquitin-proteasome system (UPS). In the UPS, ubiquitin-conjugating enzymes and ubiquitin ligases append poly-ubiquitin chains onto misfolded protein substrates signaling for their degradation. The kinetics of protein ubiquitylation are paramount since a balance must be achieved between the rapid removal of misfolded proteins versus providing sufficient time for protein chaperones to attempt refolding. To uncover the molecular basis for how PQC substrate ubiquitylation rates are controlled, the reaction catalyzed by nuclear ubiquitin ligase San1 was reconstituted in vitro. Our results demonstrate that San1 can function with 2 ubiquitin-conjugating enzymes, Cdc34 and Ubc1. While Cdc34 and Ubc1 are both sufficient for promoting San1 activity, San1 functions preferentially with Ubc1, including when both Ubc1 and Cdc34 are present. Notably, a homogeneous peptide that mimics a misfolded PQC substrate was developed and enabled quantification of the kinetics of San1-catalyzed ubiquitylation reactions. We discuss how these results may have broad implications for the regulation of PQC-mediated protein degradation. Advisors/Committee Members: Gary Kleiger, Ernesto Abel-Santos, Hong Sun, Nora Caberoy.

Subjects/Keywords: Biochemistry; Chemistry

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APA (6th Edition):

Ibarra, R. L. (2016). The San1 Ubiquitin Ligase Functions Preferentially with Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control. (Masters Thesis). University of Nevada – Las Vegas. Retrieved from https://digitalscholarship.unlv.edu/thesesdissertations/2783

Chicago Manual of Style (16th Edition):

Ibarra, Rebeca Lea. “The San1 Ubiquitin Ligase Functions Preferentially with Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control.” 2016. Masters Thesis, University of Nevada – Las Vegas. Accessed June 20, 2019. https://digitalscholarship.unlv.edu/thesesdissertations/2783.

MLA Handbook (7th Edition):

Ibarra, Rebeca Lea. “The San1 Ubiquitin Ligase Functions Preferentially with Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control.” 2016. Web. 20 Jun 2019.

Vancouver:

Ibarra RL. The San1 Ubiquitin Ligase Functions Preferentially with Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control. [Internet] [Masters thesis]. University of Nevada – Las Vegas; 2016. [cited 2019 Jun 20]. Available from: https://digitalscholarship.unlv.edu/thesesdissertations/2783.

Council of Science Editors:

Ibarra RL. The San1 Ubiquitin Ligase Functions Preferentially with Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control. [Masters Thesis]. University of Nevada – Las Vegas; 2016. Available from: https://digitalscholarship.unlv.edu/thesesdissertations/2783


University of Nevada – Las Vegas

2. Treat, Michael David. The Caspase Cascade during Hibernation in the Golden-Mantled Ground Squirrel, Spermophilus lateralis.

Degree: PhD, Life Sciences, 2018, University of Nevada – Las Vegas

In several human pathologies like heart attack, stroke, neurodegenerative diseases, and autoimmune disorders, widespread cell death, or apoptosis, is a major cause of organ dysfunction and death. Hibernating golden-mantled ground squirrels, Spermophilus lateralis, experience numerous conditions during the winter that are known to be pro-apoptotic in other mammal systems (e.g. extreme hypothermia, ischemia and reperfusion, acidosis, increased reactive oxygen species, bone and muscle disuse). However, studies suggest that hibernators may invoke a protective phenotype to limit widespread cell damage and loss during the hibernation season. Could regulating apoptosis provide protection against the harmful conditions experienced during the hibernation season? Could the lessons learned from studying the mechanisms of hibernation provide insights into new therapies for human pathologies? To address potential apoptotic regulation, I systematically examined a class of crucial apoptotic regulators, the caspase cascade (caspases 1-12), for evidence of apoptotic signaling and regulation during hibernation. Caspases comprise a family of cysteine-aspartate proteases that, upon proteolytic processing and activation, participate in a complex signaling cascade involved in apoptosis and inflammation. Using ground squirrel liver, I determined the availability and activation status of caspases with western blots, performed caspase-specific enzymatic activity assays, and analyzed multiple caspase-mediated cellular events for indications of downstream caspase signaling during hibernation. Surprisingly, I found the canonical apoptotic executioner caspases 3 and 6, as well as inflammatory caspases 11 and 12, appeared activated during hibernation. Caspase activation typically has dramatic effects on enzymatic activity. For instance, in other systems, when caspase 3, the key executioner of apoptosis, is processed into the active 17 kDa (p17) fragment, caspase 3 enzymatic activity can increase >10,000X compared to the procaspase form. Therefore, caspase 3 activation is thought to commit a cell to apoptosis. I found caspase 3 p17 increased ~2X during hibernation which may indicate significant apoptotic commitment. Did these seemingly winter-activated caspases display increased activity? Using in vitro enzymatic assays, I found no indications of dramatically increased caspase activity. To better understand the implications of seeming caspase activation during hibernation, I used a systems-level approach to analyze several events downstream of caspase activation. I looked for indications of caspase 3 activity via degradation of the inhibitor of caspase-activated DNAse (ICAD), inactivation of DNA repair enzyme poly (ADP-ribose) polymerase (PARP), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) activity. Caspase 6 activity was determined via nuclear lamin A cleavage and inflammatory caspase activity was analyzed through IL-1 and IL-18 cleavage as well as serum transaminase levels. Despite the pro-apoptotic conditions of… Advisors/Committee Members: Frank van Breukelen, Andrew Andres, Nora Caberoy, Jeffery Shen, Jefferson Kinney.

Subjects/Keywords: Biology; Cell Biology; Molecular Biology

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APA (6th Edition):

Treat, M. D. (2018). The Caspase Cascade during Hibernation in the Golden-Mantled Ground Squirrel, Spermophilus lateralis. (Doctoral Dissertation). University of Nevada – Las Vegas. Retrieved from https://digitalscholarship.unlv.edu/thesesdissertations/3335

Chicago Manual of Style (16th Edition):

Treat, Michael David. “The Caspase Cascade during Hibernation in the Golden-Mantled Ground Squirrel, Spermophilus lateralis.” 2018. Doctoral Dissertation, University of Nevada – Las Vegas. Accessed June 20, 2019. https://digitalscholarship.unlv.edu/thesesdissertations/3335.

MLA Handbook (7th Edition):

Treat, Michael David. “The Caspase Cascade during Hibernation in the Golden-Mantled Ground Squirrel, Spermophilus lateralis.” 2018. Web. 20 Jun 2019.

Vancouver:

Treat MD. The Caspase Cascade during Hibernation in the Golden-Mantled Ground Squirrel, Spermophilus lateralis. [Internet] [Doctoral dissertation]. University of Nevada – Las Vegas; 2018. [cited 2019 Jun 20]. Available from: https://digitalscholarship.unlv.edu/thesesdissertations/3335.

Council of Science Editors:

Treat MD. The Caspase Cascade during Hibernation in the Golden-Mantled Ground Squirrel, Spermophilus lateralis. [Doctoral Dissertation]. University of Nevada – Las Vegas; 2018. Available from: https://digitalscholarship.unlv.edu/thesesdissertations/3335

3. Reynolds, Lauren A. The Effects of Starvation Selection on Drosophila Melanogaster Life History and Development.

Degree: PhD, Biological Science, 2013, University of Nevada – Las Vegas

In nature, animals may endure periods of famine to complete their life cycles. Starvation stress will increase in populations as climates around the world change. To predict how populations may respond to such a stress, laboratory experimentation becomes essential. The evolutionary process of adaptation, its innovations and their trade-offs, can be studied in populations experiencing starvation stress. For this purpose outbred populations ofDrosophila melanogasterwere selected for starvation resistance in the laboratory. After 60+ generations of starvation selection the starvation-selected flies have gone from surviving 2-3 days without food to 12-14 days without food. How this amazing feat of resistance is achieved in these flies is the subject of this dissertation.Drosophilahave three mechanisms for increasing their starvation resistance. 1) Increase energy reserves, 2) decrease rate of energy use, and 3) require less energy to maintain life. Here I examined each of these strategies in the starvation-selected flies. Starvation-selected flies store nearly 3 times the amount of lipids considered normal and use those lipids at a slower rate by having lowered their metabolic rate. These findings support the use of mechanisms 1 and 2 to survive starvation stress; however no evidence supporting mechanism 3 was discovered. The lipids, so important for surviving starvation, were found to be accumulated during larval development. The storage of such large amounts of lipids may also be causing a trade-off between storage of different energetic nutrients. Acquiring starvation resistance has affected other life history traits negatively. Fecundity is low in starvation-selected flies, and egg-to-puparium development is extended by at least 24 hours, decreasing the overall fitness of the starvation-selected fly populations. This extension in development is of particular interest, because the lipid stores used to resist starvation are accumulated during larval development; an extension in development may contribute to extra lipid stores. The delay in larval development is most likely due to a delay in the hormonal cascade responsible for regulating development. Larval development time was shortened significantly in flies fed 20-hydroxyecdysone (20E) early, but lipid content was only reduced by a small amount in the starvation-selected flies. Development time therefore contributes to lipid stores to some extent, but lipid metabolism during development must also play a significant role. The delay in the hormonal cascade responsible for regulating development, and no change in the rate of mass accumulation, in combination are consistent with a model developed inManduca sextathat selection for starvation resistance is positively selecting for longer development time and larger body size. This evolutionary model may have promise as a model for studying and predicting evolutionary mechanisms indrosophilaas well. Overall the starvation-selected flies provide an excellent model for investigating starvation… Advisors/Committee Members: Allen G. Gibbs, Andrew Andres, Laurel Raftery, Nora Caberoy, Amei Amei.

Subjects/Keywords: Biology; Ecology and Evolutionary Biology; Evolution; Physiology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Reynolds, L. A. (2013). The Effects of Starvation Selection on Drosophila Melanogaster Life History and Development. (Doctoral Dissertation). University of Nevada – Las Vegas. Retrieved from https://digitalscholarship.unlv.edu/thesesdissertations/1876

Chicago Manual of Style (16th Edition):

Reynolds, Lauren A. “The Effects of Starvation Selection on Drosophila Melanogaster Life History and Development.” 2013. Doctoral Dissertation, University of Nevada – Las Vegas. Accessed June 20, 2019. https://digitalscholarship.unlv.edu/thesesdissertations/1876.

MLA Handbook (7th Edition):

Reynolds, Lauren A. “The Effects of Starvation Selection on Drosophila Melanogaster Life History and Development.” 2013. Web. 20 Jun 2019.

Vancouver:

Reynolds LA. The Effects of Starvation Selection on Drosophila Melanogaster Life History and Development. [Internet] [Doctoral dissertation]. University of Nevada – Las Vegas; 2013. [cited 2019 Jun 20]. Available from: https://digitalscholarship.unlv.edu/thesesdissertations/1876.

Council of Science Editors:

Reynolds LA. The Effects of Starvation Selection on Drosophila Melanogaster Life History and Development. [Doctoral Dissertation]. University of Nevada – Las Vegas; 2013. Available from: https://digitalscholarship.unlv.edu/thesesdissertations/1876

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