Indiana University-Purdue University Indianapolis (IUPUI) / The voltage-gated sodium channels (VGSCs) are critical determinants of
neuronal excitability. They set the threshold for action potential generation. The
VGSC isoform Nav1.6 participates in various physiological processes and
contributes to distinct pathological conditions, but how Nav1.6 function is
differentially regulated in different cell types and subcellular locations is not
clearly understood. Some VGSC isoforms are subject to S-palmitoylation and
exhibit altered functional properties in different S-palmitoylation states. This
dissertation investigates the role of S-palmitoylation in Nav1.6 regulation and
explores the consequences of S-palmitoylation in modulating neuronal excitability
in physiological and pathological conditions.
The aims of this dissertation were to 1) provide biochemical and
electrophysiological evidence of Nav1.6 regulation by S-palmitoylation and
identify specific S-palmitoylation sites in Nav1.6 that are important for excitability
modulation, 2) determine the biophysical consequences of epilepsy-associated
mutations in Nav1.6 and employ computational models for excitability prediction
and 3) test the modulating effects of S-palmitoylation on aberrant Nav1.6 activity
incurred by epilepsy mutations.
To address these aims, an acyl-biotin exchange assay was used for Spalmitoylation
detection and whole-cell electrophysiology was used for channel
characterization and excitability examination. The results demonstrate that 1)
Nav1.6 is biochemically modified and functionally regulated by S-palmitoylation in
an isoform- and site-specific manner and altered S-palmitoylation status of the
channel results in substantial changes of neuronal excitability, 2) epilepsy associated Nav1.6 mutations affect different aspects of channel function, but may
all converge to gain-of-function alterations with enhanced resurgent currents and
increased neuronal excitability and 3) S-palmitoylation can target specific Nav1.6
properties and could possibly be used to rescue abnormal channel function in
diseased conditions. Overall, this dissertation reveals S-palmitoylation as a new
mechanism for Nav1.6 regulation. This knowledge is critical for understanding
the potential role of S-palmitoylation in isoform-specific regulation for VGSCs and
providing potential targets for the modulation of excitability disorders. / 2022-05-06
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/22733 |
| Date | 04 1900 |
| Creators | Pan, Yanling |
| Contributors | Meyer, Jason S., Cummins, Theodore R., Hudmon, Andy, Jin, Xiaoming, Obukhov, Alexander G. |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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