DOI
https://doi.org/10.25772/1Y7B-3D64
Defense Date
2017
Document Type
Thesis
Degree Name
Master of Science
Department
Physiology and Biophysics
First Advisor
Dr. Lei Zhou
Abstract
SH3 and multiple ankyrin repeat domains 3 (SHANK3) is a multidomain scaffold protein that is highly augmented in the postsynaptic density (PSD) of excitatory glutamatergic synapses within the central and peripheral nervous systems. SHANK3 links neurotransmitter receptors, ion channels, and other critical membrane proteins to intracellular cytoskeleton and signal transduction pathways. Mutations in SHANK3 are linked with a number neuropsychiatric disorders including autism spectrum disorders (ASDs). Intellectual disability, impaired memory and learning, and epilepsy are some of the deficits commonly associated with ASDs that result from mutations in SHANK3. Interestingly, these symptoms show some clinical overlap with presentations of human neurological disorders involving hyperpolarization-activated cyclin nucleotide-gated (HCN) channels. In fact, it has recently been demonstrated in human neurons that SHANK3 haploinsufficiency causes Ih-channel dysfunction, and that SHANK3 has a physical interaction with HCN channels via its ANKYRIN repeat domain. These insights suggest that SHANK3 may play important roles in HCN channel expression and function, and put forward the idea that HCN channelopathies may actually encourage some of the symptoms observed in patients with SHANK-deficiency related ASDs. In this study, we provide preliminary data that suggests the ANK domain of SHANK3 interacts with COOH portion of HCN1. We also exploited the differences between two mouse models of autism to show that a subset of SHANK3 isoforms may be involved in the proper expression and function of HCN channels. We found that HCN2 expression is significantly decreased in a mouse model lacking all major isoforms of SHANK3 (exons 13-16 deleted; Δ13-16), while HCN2 expression is unaltered in a mouse model only lacking SHANK3a and SHANK3b (exons 4-9 deleted; Δ4-9). Surprisingly, we also found that HCN4 expression is altered in SHANK3Δ13-16, but not SHANK3Δ4-9. Taken together, our results show HCN channelopathy as a major downstream carrier of SHANK3 deficiency.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
8-4-2017
Included in
Biochemistry Commons, Genetics Commons, Molecular Biology Commons