Subcellular localization of estrogen receptor beta in mouse hippocampus

While estrogen receptors have been known to represent estrogen-dependent transcription factors as part of the nuclear receptor family, a putative membrane-bound form of estrogen receptors has been suggested. Since estrogen receptor beta (ERbeta) is reportedly abundant in the hippocampus and other regions of the central nervous system, subcellular localization of ERbeta in mouse hippocampus was investigated. ERbeta was predominantly found in nuclear, synaptosomal and synaptic membrane fractions, particularly this last fraction. Immunocytochemical investigation using the NG108-15 neuroblastoma-glioma hybridoma cell line indicated that ERbeta is predominantly localized in cell membranes and nuclei. These results suggest that ERbeta localizes on synaptic membranes and may represent an important regulator of intracellular signal transduction from membrane to cytosol in hippocampal neurons.