Proteomic identification of the GPER1 interactome

The G-protein coupled estrogen receptor GPER1 is thought to mediate rapid estrogen signaling at the membrane. Despite considerable efforts over the last years, its physiological ligand(s), interactors, and regulators are still very poorly understood. This is particularly problematic at a time when the inducibility of GPER1 activity has been challenged. We therefore investigated both activity and interactome of GPER1. We could confirm that GPER1 can behave as a constitutivley active signaling protein. Using proximity labelling and immunoprecipitation coupled to mass spectrometry, we explored the GPER1 interactome. Intersecting the results of the two proteomic approaches and validating some candidate interactors, we generate a GPER1 a resource, which may be useful for further functional studies in the future.