Document Type

Honors Capstone Project

Date of Submission

Spring 5-2017

Capstone Advisor

Peter Calvert

Honors Reader

Corey White

Capstone Major

Biology

Capstone College

Arts and Science

Audio/Visual Component

no

Capstone Prize Winner

no

Won Capstone Funding

no

Honors Categories

Sciences and Engineering

Subject Categories

Biotechnology

Abstract

Ciliopathies are a class of genetic diseases which affect the function of primary cilium within multiple organs throughout the body. Although ciliopathies are known to present high morbidity and mortality rates, there are no current cures and only a limited amount of treatments. A universal function of cilia is to regulate cellular activities through the transduction of signals. Disruption of the localization of proteins following the reception of a stimuli can be responsible for the phenotypic effects of dysfunctioning cilia in ciliopathies. In order to address the pathogenesis, we must first understand how proteins move within the cilia, so that we can begin to postulate treatments for ciliopathies. In vision, the light-sensing photoreceptors have a connecting cilium which is disrupted in retinal degeneration. As retinal degeneration is a phenotypic effect of ciliopathies, the inspection of how cilia function to transduce signals, would provide insight on the treatment of this class of diseases. By utilizing transgenic rod photoreceptors from the model organism of Xenopus laevis, we were able to investigate properties of proteins potentially responsible for their translocation via the connecting cilium. Through the manipulation of characteristics generally responsible for cell localization such as charge, hydrophobicity, and size, we were able to determine patterns in the resulting localization of such protein probes. Analysis of these experiments in conjunction with current literature regarding the characteristics of the proteins involved in the phototransduction cascade allowed for a deeper understanding of the applicability to ciliopathy patients. Specifically, my research involved relating the translocation of transducin, phosphodiesterase 6, recoverin, and rhodopsin kinase to the experimental evidence of translocation of genetically engineered protein probes within the rod photoreceptors of Xenopus laevis. It was apparent the presence of the hypothesized characteristics of lipidation, poly-charged regions, and size of the proteins had an effect on their localization via the connecting cilium, however, there appeared to be overwhelming evidence which indicated conformational changes in response to protein-protein interactions within the cascade altered such characteristics, and consequentially their localization. This analysis and literature review provides evidence to suggest for the development of further experimental protein models, which in combination with past results can elucidate the specific influence these characteristics have. Given future experimental models which are able to account for specific conformational changes and protein-protein interactions, the relative roles of protein characteristics could quantitatively describe the role of connecting cilia. By understanding the mechanisms of the phototransduction cascade in regards to the ciliated rods, we may eventually be able to generate probes capable of specific localization for treatment of ciliopathies.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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