Membrane G-protein coupled estrogen receptor that binds to 17-beta-estradiol (E2) with high affinity, leading to rapid and transient activation of numerous intracellular signaling pathways. Plays a role in the embryonic development of sensory and motor neurons. Specifically induces apoptosis and reduces proliferation of brain cells. Involved in maintenance of meiotic arrest in oocytes. Binds 17-beta-estradiol (E2) in plasma membranes with high affinity and displays rapid kinetics of association and dissociation. Homodimer. Heterodimer (By similarity). Colocalized with cadherin at the plasma membrane. Expressed in brain regions that are known to control reproduction and sex behavior. Expressed in ovary, muscle and intestine. Expressed in early germ cells of the testis, including the spermatogonia, spermatocytes, and somatic cells such as Sertoli cells. Expressed throughout early embryonic development from 0 hours post-fertilization (hpf) to 72 hpf. Expressed in blastomeres at 4 hpf. Expressed in the central nervous system at 18 hpf. Expressed in head including the anterior diencephalon, midbrain and hindbrain at 24 hpf. Expressed in trigeminal ganglia as well as in the heart, pancreas and intestinal bulb between 36 and 72 hpf (at protein level). Morpholino knockdown of the protein leads to growth retardation and developmental deformity. Belongs to the G-protein coupled receptor 1 family.