Protein structure and functions are tightly regulated. Studying the integration of multiple
modifications in single systems is a novel approach. Hisactophilin protein from Dictyostelium
discoideum, is an actin binding protein that serves to induce formation of actin filaments and is
regulated by protonation and myristoylation. Utilizing hisactophilin as a model, I determined the
effect of pH and myristoyl-switching on actin binding and filament induction using fluorescence
spectroscopy, light scattering, and time-course electron microscopy. Results revealed the
accessible myristoyl group slows binding and the rate of actin polymerization compared to when
the group is sequestered. Hisactophilin induces pH-dependent actin aggregates before
reorganizing them into filaments and bundles. Hisactophilin mutants impact initial actin binding
and the kinetics of the aggregated state. I determined the cooperativity of myristoylation and
protonation as interdependent protein regulatory mechanisms, their impact on actin binding and
proposed a novel mechanism for actin polymerization as a result of these integrated regulators. / NSERC
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OGU.10214/5264 |
| Date | 09 January 2013 |
| Creators | McRorie, Paul Alexander |
| Contributors | Dawson, John |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | http://creativecommons.org/licenses/by/2.5/ca/ |
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