# Sodium Influx Assay for Measurement of TRPM7 Channel Activity in Intact Cells

> **NIH NIH R21** · WRIGHT STATE UNIVERSITY · 2020 · $221,000

## Abstract

T lymphocyte activation and proliferation is essential for the human adaptive immune response. It is well
established that calcium and magnesium signaling pathways play a crucial role in this process and their
impairments result in various forms of immunodeficiency. Several players involved in calcium and magnesium
influx have been identified at the molecular level. One of them, TRPM7, a protein with dual ion channel and
serine/threonine kinase function is permeable to both calcium and magnesium. TRPM7 is required for T-cell
development and activation of macrophages. Until now TRPM7 channel function has been studied primarily
with patch-clamp electrophysiology. Detailed understanding of TRPM7 involvement in immune cellular
signaling has been hampered by the lack of specific drug modulators of this channel. In order to develop
effective high throughput drug screening assays for this purpose, novel ways of detecting channel activity in
intact cells are necessary. This proposal is a proof-of-concept study of an intact cell fluorescence-based Na+
influx assay for measuring TRPM7 channel activity and its adaptation to high throughput format. The assay
takes advantage of the biophysical properties of TRPM7 channels, specifically, drastic changes in current-voltage relation upon changes in extracellular divalent cation (Ca2+ or Mg2+) concentrations. Channel activity
will be evaluated using intracellular Na+ concentrations as a readout. TRPM7 conduction and gating mutants
identified electrophysiologically, will be used for Na+ influx assay validation. The Na+ flux assay will allow us to
compare cellular Na+ changes in response to overexpression and mutagenesis of TRPM7. At the conclusion of
the proposed studies we will have developed new tools for high throughput cell-based assays of TRPM7 for
use in drug discovery.

## Key facts

- **NIH application ID:** 10057778
- **Project number:** 1R21AI144337-01A1
- **Recipient organization:** WRIGHT STATE UNIVERSITY
- **Principal Investigator:** Juliusz Ashot Kozak
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $221,000
- **Award type:** 1
- **Project period:** 2020-06-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10057778

## Citation

> US National Institutes of Health, RePORTER application 10057778, Sodium Influx Assay for Measurement of TRPM7 Channel Activity in Intact Cells (1R21AI144337-01A1). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/10057778. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*