In the brain, many pathophysiological events are accompanied by acidification of the extracellular environment. Unsurprisingly, neurons often show robust electrophysiological responses during such changes in extracellular pH. Acid sensing ion channels (ASICs) mediate the vast majority of these currents and the last few years have seen a substantial increase in our understanding of ASIC neurobiology. Because of this research, ASICs have been implicated in cell death following stroke, in pain, in fear related memory and in drug addiction amongst other disorders. However, we have not seen a corresponding surge in our understanding of how ASICs operate at a molecular level. Without such knowledge, we cannot translate our growing awareness of neurobiology into useful treatments. The candidate will combine his expertise in electrophysiology and fluorescence with new training in cryo-electron microscopy (cryo-EM) to bridge the gap between ASIC neurobiology and biophysics. This will be done through three Aims. During Specific Aim 1 in the K phase, the candidate will obtain high resolution cryo-EM structures of ASIC1a apo and desensitized states. New training in protein purification will be provided from Dr. Jayaraman and ASIC-specific advice from Dr. Gonzales. Dr. Serysheva will provide expert instruction in cryo-EM imaging and 3D reconstruction to a level where the candidate can perform the experiments independently. These structures will provide the first glimpse of the apo state and determine if steady-state desensitization (provoked by pH's near 7) is the same conformation as desensitization following activation (pH's near 5). The R phase will begin with Aim 2 where the candidate and his trainees will use concatenated subunits to determine the stoichiometry of activation and establish if conformational changes are concerted across subunits.
In Aim 3, the candidate and his trainees will obtain high resolution cryo-EM images of heteromeric ASICs, the predominant population in the brain. This combination of functional information and structural data will help fulfill the candidates two near term goals of contributing essential insight into th fundamental operation of ASICs and emerging as a leader in the field of ASIC gating. Moreover, these studies will provide preliminary data to develop a competitive R01 application focusing on ASIC heteromeric structure and function. This K99/R00 award will also better position the candidate to satisfy the long term goals of rendering the effect of ASIC mutations or manipulations predictable and to help drive efforts to develop more selective and useful pharmacological agents.

Public Health Relevance

Acute insults to the brain's normal operation, such as stroke, traumatic injury or seizures, trigger the acidification of the extracellular environment. Acid Sensing Ion Channels (ASICs) are the primary sensors of this acidification and their aberrant activation increases the accompanying cellular damage. Here we will study the molecular details of how ASICs are activated and desensitized with a view to guiding drug development efforts.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Transition Award (R00)
Project #
4R00NS094761-03
Application #
9477168
Study Section
Special Emphasis Panel (NSS)
Program Officer
Silberberg, Shai D
Project Start
2017-07-01
Project End
2020-06-30
Budget Start
2017-07-01
Budget End
2018-06-30
Support Year
3
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Rochester
Department
Pharmacology
Type
School of Medicine & Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Chen, Jinjun; Li, Lingyong; Chen, Shao-Rui et al. (2018) The ?2?-1-NMDA Receptor Complex Is Critically Involved in Neuropathic Pain Development and Gabapentin Therapeutic Actions. Cell Rep 22:2307-2321
Coombs, Ian D; MacLean, David M; Jayaraman, Vasanthi et al. (2017) Dual Effects of TARP ?-2 on Glutamate Efficacy Can Account for AMPA Receptor Autoinactivation. Cell Rep 20:1123-1135
Dolino, Drew M; Chatterjee, Sudeshna; MacLean, David M et al. (2017) The structure-energy landscape of NMDA receptor gating. Nat Chem Biol 13:1232-1238