TABLE 3

Binding affinities (Ki) and EC50 values of ligand-induced BRET for MT2 homodimers in HEK 293 cells

MT2-Rluc and MT2-YFP receptors were expressed at a 1:3 ratio (∼80 fmol/mg of protein) and 125I-MLT competition binding experiments and BRET measurements were performed as described under Materials and Methods and in Fig. 3. Data are means ± S.E. of at least three independent experiments each performed in triplicate.

Ligands Ki EC50Emax
nM nM %
Melatonin 0.27 ± 0.01 26 ± 7.75 173 ± 20
S20098 0.06 ± 0.05 14.2 ± 13.6 143 ± 9
S22153 3 ± 1.90 47 ± 24 147 ± 18
S20928 60 ± 0.10 368 ± 234 126 ± 6
4P-PDOT 0.35 ± 0.31 40.4 ± 12 146 ± 3
Luzindole 7.23 ± 4.5 126 ± 57.2 150 ± 8
S24773 5.70 ± 1.7 32.7 ± 16.4 161 ± 6
2-iodomelatonin 0.16 ± 0.03 4.4 ± 1.95 113 ± 3