2. Academic Validation
  3. ATM-SPARK: A GFP phase separation-based activity reporter of ATM

ATM-SPARK: A GFP phase separation-based activity reporter of ATM

  • Sci Adv. 2023 Mar;9(9):eade3760. doi: 10.1126/sciadv.ade3760.
Xiaoquan Li 1 2,  Chan-I Chung 1 2,  JunJiao Yang 1 2,  Sibapriya Chaudhuri 3,  Pamela N Munster 3,  Xiaokun Shu 1 2
Affiliations

Affiliations

  • 1 Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA.
  • 2 Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
  • 3 Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA, USA.
PMID: 36857446 DOI: 10.1126/sciadv.ade3760
Abstract

The kinase ataxia telangiectasia mutated (ATM) plays a key role in the DNA damage response (DDR). It is thus essential to visualize spatiotemporal dynamics of ATM activity during DDR. Here, we designed a robust ATM activity reporter based on phosphorylation-inducible green Fluorescent protein phase separation, dubbed ATM-SPARK (separation of phases-based activity reporter of kinase). Upon ATM activation, it undergoes phase separation via multivalent interactions, forming intensely bright droplets. The reporter visualizes spatiotemporal dynamics of endogenous ATM activity in living cells, and its signal is proportional to the amount of DNA damage. ATM-SPARK also enables high-throughput screening of biological and small-molecule regulators. We identified the protein Phosphatase 4 that blocks ATM activity. We also identified BGT226 as a potent ATM Inhibitor with a median inhibitory concentration of ~3.8 nanomolars. Furthermore, BGT226 sensitizes Cancer cells to the radiomimetic drug neocarzinostatin, suggesting that BGT226 might be combined with radiotherapeutic treatment. ATM-SPARK achieves large dynamic range, bright fluorescence, and simple signal pattern.

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