Figure 2.

The agonist-independent IP production of clones highly responsive to CGP42112A. Bars indicate the levels obtained without doxycycline pretreatment (receptor expression) as a percentage of the levels obtained after pretreatment with 1 ng/ml doxycycline (no receptor expression), normalized to 200,000 sites/cell (except for the first three clones, which were poorly expressed). The amino acid substitutions (one letter amino acid code; Z, stop codon) found to be responsible for much or slightly higher sensitivity to CGP42112A are in bold or underlined, respectively. Results are means ± SEM of three independent experiments. *, different from WT (P < 0.05); †, different from I245T mutant (P < 0.05); ‡, different from F44S-T175A-F182Y-K325Z-L112H mutant (P < 0.05).