The authors state: "In this study, we report that, in the absence of neuronal activity, MeCP2 binds specifically to BDNF promoter III and functions as a negative regulator of BDNF expression. In response to neuronal activity-dependent calcium influx into neurons, MeCP2 becomes phosphorylated and is released from the BDNF promoter, thereby permitting BDNF promoter III-dependent transcription." Reading this statement in isolation, it would be easy to have the impression that MeCP2 works as a negatively acting transcription factor. However, based on the summary of the paper provided above, MeCP2 acts as a _____. (Hint: think chromatin remodeling complex)