Date of Award
Spring 2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Molecular Biophysics and Biochemistry
First Advisor
Paulsen, Candice
Abstract
Transient receptor potential (TRP) channels are sensory receptors expressed throughout the peripheral nervous system that help shape how we respond to our environment. TRPA1 has been identified as a key component in the transition from acute to chronic pain and inflammation making it a prime target for development of novel analgesics. Calcium has been shown to regulate TRPA1 by rapidly potentiating channel activity followed by rapid desensitization. While the effects of calcium on TRPA1 activity have been well-described, the mechanisms governing these calcium effects have been difficult to elucidate. Work described within this thesis details the discovery of a novel calmodulin (CaM) binding site (CaMBS) that is required for rapid desensitization of TRPA1. The CaMBS is located within the distal, disordered C-terminus and is evolutionarily conserved across vertebrate TRPA1 orthologs. Mutagenesis of the CaMBS results in total loss of CaM binding under basal cellular conditions and leads to channel hyperactivity through a dramatic slowing of calcium-mediated desensitization. CaM operates as an auxiliary subunit of TRPA1 that is necessary for proper channel function and regulation. This represents a step forward in understanding calcium regulation of TRPA1 activity and necessitates a closer look at previously proposed sites of calcium-mediated regulation. A calcium binding site was identified between two transmembrane helices of TRPA1 (S2-S3 CBS) and proposed to regulate both potentiation and desensitization, and a different CaM binding domain (CaMBD) was also proposed to regulate both potentiation and desensitization. This thesis work suggests a model of TRPA1 calcium regulation where the CaMBS is the main driver of calcium-mediated desensitization, the CaMBD is an ancillary site with smaller effects on desensitization, and the S2-S3 CBS primarily serves functions in structural role.
Recommended Citation
Sanders, Justin, "Uncovering a Critical Role for Calmodulin in Calcium-Dependent Regulation of the Nociceptor TRPA1" (2024). Yale Graduate School of Arts and Sciences Dissertations. 1465.
https://elischolar.library.yale.edu/gsas_dissertations/1465
