Kinase experiment:

TAF1 binding assays are conducted using the EPIgeneous Binding Domain kit B. Binding is determined by the displacement of an acetylated biotin peptide from a GST-tagged TAF1 protein using HTRF with a Eu3+-conjugated GST antibody donor and streptavidin-conjugated acceptor. Compounds (CeMMEC1) are dispensed into assay plates, ProxiPlate-384 Plus using an Echo 525 Liquid Handler. Binding assays are conducted in a final volume of 20 μL with 5 nM TAF1-GST, 50 nM peptide (SGRGK (ac)GGK (ac)GLGK (ac)GGAK (ac)RHRK (biotin)-acid), 6.25 nM Streptavidin-XL665, 1:200 Anti-GST-Eu3+ cryptate and 0.1% DMSO. Assay reagents are dispensed into plates using a Multidrop combi and incubated at room temperature for 3 h. Fluorescence is measured using a PHERAstar microplate reader using the HTRF module with dual emission protocol (A = excitation of 320 nm, emmission of 665 nm, and B = excitation of 320 nm, emission of 620 nm). Raw data are processed to give an HTRF ratio (channel A/B × 10,000), which is used to generate IC50 curves[1].

Cell experiment:

Cells are seeded on clear flat-bottom 96-well or 384-well plates and treated with the indicated compounds (CeMMEC1) for the specified conditions. Live-cell imaging pictures are taken with the Operetta High Content Screening System, 20× objective and nonconfocal mode[1].

CeMMEC1 is an inhibitor of BRD4, and also has high affinity for TAF1, with an IC50 of 0.9 uM for TAF1, and a Kd of 1.8 uM for TAF1 (2).

CeMMEC1 is an inhibitor of BRD4, and also has high affinity for TAF1, with an IC50 of 0.9 uM for TAF1, and a Kd of 1.8 uM for TAF1 (2) and slso shows high affinity for the bromodomains of CREBBP, EP300, BRD9. CeMMEC1 (1, 10, 20 uM) decreases the number of THP1 cells in S phase in a dose manner. CeMMEC1 also induces apoptosis. CeMMEC1 in combination with (S)-JQ1 displays potently impaired cell viability than treatment alone[1].

References:
[1]. Sdelci S, et al. Mapping the chemical chromatin reactivation landscape identifies BRD4-TAF1 cross-talk. Nat Chem Biol. 2016 Jul;12(7):504-10.