Doctor of Philosophy / Biochemistry and Molecular Biophysics Interdepartmental Program / Gerald R. Reeck / Armet is a bifunctional protein that is apparently universally distributed among
multicellular animal species, vertebrate and invertebrate alike. A member of the Unfolded
Protein Response, (UPR) Armet promotes survival in cells that are under endoplasmic-reticulum
(ER) stress. I have carried out biophysical studies on human Armet looking for compounds that
bind to Armet and hence could reduce its anti-apoptotic function, thus potentially joining the
growing class of pro-apoptotic drugs. Performed primarily with 1H-15N HSQC NMR, ligand
studies showed that approximately 60 of the 158 residues are potentially involved with binding.
The 60 residues are distributed throughout both domains and the linker suggesting multi-domain
interaction with the ligand. Circular dichroism studies showed heat denaturation in a two-step
unfolding process with independent unfolding of both domains of Armet with Tm values near
68°C and 83 C with the C-terminal domain unfolding first, as verified by 1H-15N HSQC NMR
measurements.
I also provide the first identification of UPR transcripts in pea aphids, Acyrthosiphon
pisum, the genetic model among aphids. I measured transcript abundance with hope of finding
future transcriptional targets for pest mitigation. I identified 74 putative pea aphid UPR
components, and all but three of the components have higher transcript levels in aphids feeding
on plants than those that fed on diets. This activated UPR state is attributed to the need for saliva
proteins for plant feeding.
Because aphids are agriculturally significant pests, and saliva is pivotal to their feeding
on host plants, genes that encode saliva proteins may be targets for pest mitigation. Here I have
sought the aphid’s saliva proteome by combining results obtained in several laboratories by
proteomic and transcriptomic approaches on several aphid species. With these data I constructed
a tentative saliva proteome for the pea aphid by compiling, collating, and annotating the data
from several laboratories. I used RNA-seq to verify the transcripts in pea aphid salivary glands,
thus expanding the proposed saliva proteome from approximately 50 components to around 130
components, I found that transcripts of saliva proteins are upregulated during plant feeding
compared to diet feeding.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/35218 |
| Date | January 1900 |
| Creators | Balthazor, James |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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