Prostaglandin F receptor-alternative splice variant heterodimer (FP-altFP heterodimer)

The Prostaglandin F receptor-alternative splice variant heterodimer, commonly known as the FP-altFP heterodimer or the prostamide receptor, is a specialized G protein-coupled receptor complex formed by the association of the wild-type Prostaglandin F (FP) receptor and its truncated splice variants, particularly altFP4 (2, 3). While the monomeric FP receptor is the primary target for Prostaglandin F2α, this heterodimeric complex exhibits a unique pharmacological sensitivity to prostamides, such as bimatoprost, which are ethanolamide derivatives of prostaglandins (6, 7). The formation of this complex is thought to create a specific binding pocket that accommodates the bulky ethanolamide group of prostamides, a feature not present in the standard FP receptor (2, 13). Biologically, this receptor complex is expressed in ocular tissues like the ciliary smooth muscle and trabecular meshwork, where it plays a critical role in regulating the outflow of aqueous humor to maintain intraocular pressure (2, 16). It is the primary therapeutic target for bimatoprost in the treatment of open-angle glaucoma and ocular hypertension (1, 13). Beyond its ocular role, the receptor is also found in hair follicles, where its activation contributes to the increased eyelash growth and darkening observed as common side effects of prostamide therapy (5).

Other names

Prostamide receptorBimatoprost receptorFP/altFP4 heterodimerFP-altFP receptor complexProstamide-sensitive receptor

Agonist binding to the heterodimer complex triggers Gq-mediated signaling, leading to increased uveoscleral and trabecular outflow of aqueous humor, which reduces intraocular pressure.