Class A GPCR: Di/Oligomerization of Glycoprotein Hormone Receptors

G protein-coupled receptor (GPCR) dimerization and oligomerization was first described over 2 decades ago, contributing to the recent paradigm shift in GPCR signaling of a simplistic, archetypal view involving single receptors activating specific heterotrimeric G proteins at the cell surface, to one of an increasing complex receptor signaling system. However, our understanding of how dimerization and oligomerization, particularly homomerization, generates functional diversity in GPCR signaling is poorly understood. For the Class A/rhodopsin subfamily of glycoprotein hormone receptors (GpHRs), di/oligomerization has been demonstrated to play a significant role in regulating its signal activity at a cellular and physiological level and even pathophysiologically. Here we will describe and discuss the developments in our understanding of GPCR oligomerization, primarily the role of homomeric receptor complexes, in both health and disease, from the study of this unique and complex subfamily of GPCRs.