AIB1 shows variation in interaction with ERβTAD and expression as a function of age in mouse brain

Estrogen mediates its multiple functions in the brain through the recruitment of a number of interacting proteins. In this paper, we report the identification of 160 kD interacting nuclear protein of estrogen receptor (ER)β-transactivation domain (TAD) as amplified in breast cancer 1(AIB1) by pull down assay, immunoblotting, far-western analysis and immunoprecipitation. Further we show the age dependent interaction and expression of AIB1 in the brain of young (6 weeks), adult (25 weeks) and old (70 weeks) AKR strain mice of both sexes. The immunoprecipitation data revealed higher interaction of AIB1 in young than adult and old male mice. In contrast, the interaction was low in young, increased in adult but decreased in old female. However, immunoblotting showed age related increase in the expression of AIB1 in both male and female mice. Further, the level of interaction of AIB1 with ERβTAD in young and old male was significantly higher than female of same age, whereas the expression of AIB1 in adult and old female was significantly higher than male of same age. These data suggest that such age dependent variation in the interaction of AIB1 with ERβTAD and its expression may be helpful to regulate estrogen-mediated gene functions during aging and neurodegenerative diseases.