Transmembrane peptide 4 and 5 of APJ are essential for its heterodimerization with OX1R

• Published in: Biochemical and biophysical research communications 2020-01, Vol.521 (2), p.408-413
• Main Authors: Wan, Lei, Xu, Fangfang, Liu, Chang, Ji, Bingyuan, Zhang, Rumin, Wang, Peixiang, Wu, Fei, Pan, Yanyou, Yang, Chunqing, Wang, Chunmei, Chen, Jing
• Format: Article
• Language: English
• Subjects: APJ; Co-internalization; GPCR; Heterodimerization; Interface; OX1R
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2019.10.146

Increasing evidence indicates some G protein-coupled receptors function as a heterodimer, which provide a novel target for therapeutics investigation. However, study on the receptor-receptor interaction interface, a potent target on interfering dimer formation, are still limited. Here, using bioluminescence resonance energy transfer (BRET) combined with co-immunoprecipitation (Co-IP), we found a new constitutive GPCR heterodimer, apelin receptor (APJ)-orexin receptor type 1 (OX1R). Both APJ and OX1R co-internalized when constantly subjected to cognate agonist (apelin-13 or orexin-A) specific to either protomer. Combined with BRET and immunostaining, the in vitro synthesized transmembrane peptides (TMs) interfering experiments suggests that TM4 and 5 of APJ act as the interaction interface of the APJ-OX1R heterodimer, and co-internalization could be disrupted by these peptides as well. Our study not only provide new evidence on GPCR heterodimerization, but address a novel heterodimerization interface, which can be severed as a potential pharmacological target. •APJ and OX1R could form a constitutive heterodimer.•Transmembrane peptides 4 and 5 serve as the interaction interface of the dimer.•Both protomers co-internalize when subject to agonist specific to either protomer.