Historical Perspectives: From Monomers to Dimers and Beyond, an Exciting Journey in the World of G Protein-Coupled Receptors

G protein-coupled receptors (GPCR)s are the largest family of proteins in the human genome, and for a long time they were thought to be monomeric in nature. Nowadays, this belief seems rather eccentric, and the concept of lonely GPCRs wandering around the cell membrane has been replaced by a different view in which GPCRs have instead a very active social life, with promiscuous coupling among, but not limited to, their family members. This short chapter summarizes the major steps that have led scientists to change their convictions, from strong supporters of GPCR individualism to enthusiastic appreciators of GPCR camaraderie. A fascinating journey started more than 40 years ago that keeps and will continue to fascinate and excite the scientific community for years to come.