Expression of Trk A and Src and their interaction with ERβ ligand binding domain show age and sex dependent alteration in mouse brain.

Following the binding of estrogen to estrogen receptor (ER)β ligand binding domain (LBD) and its interaction with the target genes, a host of nuclear proteins is recruited to regulate the expression of specific genes(s). It is not known which proteins interact with ERβLBD and whether they vary with age and sex in the brain. Therefore, using pull down assay, immunoprecipitation and immunoblotting, we report that cell signaling molecules Trk A and Src interacted with ERβLBD, and showed alteration in the level of interaction and expression in the brain of AKR strain young (6 weeks), adult (25 weeks) and old (70 weeks) mice of both sexes. Trk A showed decreasing interaction with age, and lower expression in adult as compared to young and old males, whereas female mice exhibited decline in both interaction and expression as a function of age. On the other hand, Src interaction with ERβLBD decreased, but its expression increased with age in males, whereas the interaction and expression was lower in adult but higher in old as compared to young females. These findings suggest the implication of Trk A and Src in ERβ mediated brain functions and related disorders during aging.