# Activity-dependent probes for spatially-defined proteomics

> **NIH NIH DP2** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2023 · $875,294

## Abstract

Project Summary
Uncovering the molecular properties of functionally-defined neural ensembles is essential for understanding
how these networks give rise to circuit function and animal behavior. This proposal aims to develop and deploy
new molecular technologies that will enable the sub-cellular tagging and enrichment of proteins in activated
subgroups of neurons in the brain. Linking protein expression to neural function at a large and unbiased scale
is currently not possible with existing technologies. Thus the research program proposed here will fill a critical
unmet gap in the molecular toolbox for neuroscientists. While prior technologies have focused on gaining
genetic access to the genome or transcriptome of activated neurons, the approach here will identify the actual
proteins expressed in specific subcellular compartments of functionally-relevant neurons. This is a key
distinction, as gene expression alone cannot reveal to the actual physical location and expression patterns of
translated proteins – which are the ultimate molecules that carry out the specific biochemical functions of our
cells. To enable this goal, new activity-dependent proximity labeling probes will be developed using protein
engineering. These probes will be improved and optimized through high-throughput screens performed in
cultured cells, and then adapted for use in mammalian neurons. Concurrently, the probes will be tested and
characterized in the mouse brain to improve and benchmark their function. To demonstrate their utility, the
activity-dependent probes will be used to tag the proteins that are present in neurons undergoing high neural
activity in response to a behavioral drug experience in mice. 5-MeO-DMT is a hallucinogenic drug that in
humans has been associated with therapeutic potential for treating neuropsychiatric diseases. Neurons
activated by 5-MeO-DMT will be labeled by the activity-dependent probes, and their spatial distribution
throughout the brain will be examined using the fluorescent read-out of the new molecular enzyme. In addition,
the probes will also tag the proteins that are present in these activated neurons, allowing the enrichment and
unbiased profiling of these molecules using liquid chromatography mass spectrometry (proteomics). The sub-
cellular proteome of these neurons will provide essential biological insight into the mechanism of
hallucinogenic drugs, in addition to providing potential downstream targets for new drug discovery and
development. More broadly, the new probes will be distributed freely to the neuroscience community to enable
the study of protein expression in functionally-relevant populations of neurons.

## Key facts

- **NIH application ID:** 10686705
- **Project number:** 1DP2MH136588-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Christina Kim
- **Activity code:** DP2 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $875,294
- **Award type:** 1
- **Project period:** 2023-09-01 → 2025-01-15

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10686705

## Citation

> US National Institutes of Health, RePORTER application 10686705, Activity-dependent probes for spatially-defined proteomics (1DP2MH136588-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10686705. Licensed CC0.

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