Date of Award
Spring 2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Molecular Biophysics and Biochemistry
First Advisor
Paulsen, Candice
Abstract
Roughly one third of Americans suffer from chronic pain and inflammation, yet so far little progress has been made to develop new pain remedies beyond non-steroidal anti-inflammatory agents and opioids, which often harbor deleterious side-effects. The identification and mechanistic analysis of pain-initiating receptors in peripheral nociceptor neurons is therefore an attractive approach to develop new analgesic and anti-inflammatory therapeutics. Transient receptor potential (TRP) ion channels are the largest group of receptors expressed in nociceptor neurons and are capable of transducing noxious thermal and chemical stimuli into cation influx that triggers pain signaling. My thesis work focuses on one such TRP channel, TRP “Ankyrin” 1 (TRPA1). In this dissertation, I describe a novel mechanism we uncovered for TRPA1 gain-of-function via a R919* truncation mutation associated with CRAMPT syndrome. Using functional and biochemical assays, we reveal that the R919* mutant co-assembles with WT TRPA1 into functional heteromeric channels. The R919* mutant hyperactivates channels by enhancing their agonist sensitivity and calcium permeability, which could account for the observed neuronal hypersensitivity-hyperexcitability symptoms. This work reveals important structural characteristics of TRPA1, and uncovers how TRPA1 can contribute to disease states in different tissue systems. During my doctoral studies I have also laid the groundwork for determining crucial regulatory processes at the distal disordered C-terminus (DDC), a region of TRPA1 spanning 41 amino acids that is structurally unresolved and largely overlooked in our field. I find that a cluster of highly conserved acidic residues within the DDC are crucial to TRPA1 activity, plasma membrane trafficking, and Ca2+- mediated regulation. Our lab has identified a novel calmodulin (CaM) binding site within the TRPA1 DDC, and I posit that CaM binding may modulate other conserved residues within the DDC to facilitate functional regulation of TRPA1. In all, the work put forth in this dissertation paves multiple avenues toward unveiling long-sought mechanisms of TRPA1 regulation and illuminating new strategies for treating TRPA1-related pathologies.
Recommended Citation
Bali, Avnika Prasad, "A “Spicy” Molecular Mechanism of TRPA1 Hyperactivation Conferred by a Disease Mutant and Insights into C-terminal Regulatory Components" (2024). Yale Graduate School of Arts and Sciences Dissertations. 1364.
https://elischolar.library.yale.edu/gsas_dissertations/1364
