Accéder au contenu
Merck

Spatial bias in cAMP generation determines biological responses to PTH type 1 receptor activation.

Science signaling (2021-10-06)
Alex D White, Karina A Peña, Lisa J Clark, Christian Santa Maria, Shi Liu, Frédéric G Jean-Alphonse, Ji Young Lee, Saifei Lei, Zhiqiang Cheng, Chia-Ling Tu, Fei Fang, Nicholas Szeto, Thomas J Gardella, Kunhong Xiao, Samuel H Gellman, Ivet Bahar, Ieva Sutkeviciute, Wenhan Chang, Jean-Pierre Vilardaga
RÉSUMÉ

The parathyroid hormone (PTH) type 1 receptor (PTHR) is a class B G protein–coupled receptor (GPCR) that regulates mineral ion, vitamin D, and bone homeostasis. Activation of the PTHR by PTH induces both transient cell surface and sustained endosomal cAMP production. To address whether the spatial (location) or temporal (duration) dimension of PTHR-induced cAMP encodes distinct biological outcomes, we engineered a biased PTHR ligand (PTH7d) that elicits cAMP production at the plasma membrane but not at endosomes. PTH7d stabilized a unique active PTHR conformation that mediated sustained cAMP signaling at the plasma membrane due to impaired β-arrestin coupling to the receptor. Experiments in cells and mice revealed that sustained cAMP production by cell surface PTHR failed to mimic the pharmacological effects of sustained endosomal cAMP production on the abundance of the rate-limiting hydroxylase catalyzing the formation of active vitamin D, as well as increases in circulating active vitamin D and Ca2+ and in bone formation in mice. Thus, similar amounts of cAMP generated by PTHR for similar lengths of time in different cellular locations, plasma membrane and endosomes, mediate distinct physiological responses. These results unveil subcellular signaling location as a means to achieve specificity in PTHR-mediated biological outcomes and raise the prospect of rational drug design based upon spatiotemporal manipulation of GPCR signaling.

MATÉRIAUX
Référence du produit
Marque
Description du produit

Sigma-Aldrich
Cocktail d'inhibiteurs de protéases, for use in purification of Histidine-tagged proteins, DMSO solution
Millipore
Anticorps monoclonal anti-HA−agarose antibody produced in mouse, clone HA-7, purified immunoglobulin, PBS suspension
Sigma-Aldrich
Forskolin, Coleus forskohlii