Age-dependent decrease in the interaction of β-tubulin with estrogen receptor alpha transactivation domain in mouse brain

In the previous paper, we reported that four proteins of 100 kDa, 80 kDa, 68 kDa and 50 kDa from the mouse brain interacted with estrogen receptor (ER) α-transactivation domain (TAD) and 68 kDa protein showed age and sex dependent changes. Here, we describe the identification of 50 kDa protein as β-tubulin and changes in its interaction with age and sex in mouse brain. It is a microtubule-associated protein which binds to activation function (AF)-1 region of ERα-TAD and is involved in estrogen signaling. The extent of interaction of mouse ERα-TAD with β-tubulin was higher in adult female as compared to old female and adult male. However, the expression of β-tubulin showed no significant change with age and sex. Such age and sex dependent alteration in the interaction of β-tubulin might account for the estrogen-mediated brain functions during aging.