Single-Molecule Array (Simoa) Technology as a Highly Sensitive Screening Tool for Protein–Protein Interactions

Transcription factor
(TF) interactions are generally considered
to be weak and transient, which enables the dynamic assembly and disassembly
of transcription complexes. While advantageous for modulating cellular
physiology, requiring rapid adaptation, these characteristics make
it challenging to identify and study TF interactions using conventional
methodologies. To overcome this issue, we have adapted an ultrasensitive
single-molecule array (Simoa) assay, typically used for biomarker
detection, to screen for and identify TF–TF interactions. Leveraging
Simoa-based digital ELISA, we have screened the human transcription
factor library for interaction partners of ARX (aristaless-related
homeobox), a transcription factor associated with a wide spectrum
of neurodevelopmental disorders. Our successful application of Simoa
technology to a high-throughput screening for protein interaction
partners opens up new opportunities to study transcription factor–transcription
factor interactions, especially those that have been elusive to detect.