title: Intermolecular cross-talk between NTR1 and NTR2 neurotensin receptor promotes intracellular sequestration and functional inhibition of NTR1 receptors.
abstract: G-protein-coupled receptors (GPCR) are now regarded as being able to acquire heterodimer conformations affecting their pharmacology, signaling and trafficking. In co-immunoprecipitation studies using differentially epitope-tagged receptors, we herein provide direct evidence for heterodimerization of human neurotensin type 1 receptor (hNTR1) and type 2 receptor (hNTR2). Using chimeric constructs, we also identified the hNTR2 transmembrane 2 (TM2) to TM4 region as crucial for the formation of the dimerization interface. At the functional level, we demonstrated that the co-expression of hNTR2 suppressed hNTR1-mediated adenylate cyclase/cAMP and phospholipase C activation. Finally, confocal microscopy revealed that whereas tagged hNTR1 expressed alone were localized to the plasma membrane, co-expression of hNTR2 caused the retention of hNTR1 in sub-cellular compartments, indicating that heterodimerization with hNTR2 interferes with the proper recruitment of hNTR1 to the plasma membrane. Overall, this study proposes a novel function of NTR2 in the regulation of NTR1 activity.
authors.affiliation: Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Jae Ryoung
authors.initials: JR
authors.lastname: Hwang
authors.forename: Min Woo
authors.initials: MW
authors.lastname: Baek
authors.forename: Jeonggu
authors.initials: J
authors.lastname: Sim
authors.forename: Heung-Sik
authors.initials: HS
authors.lastname: Choi
authors.forename: Ji Man
authors.initials: JM
authors.lastname: Han
authors.forename: You Lim
authors.initials: YL
authors.lastname: Kim
authors.forename: Jong-Ik
authors.initials: JI
authors.lastname: Hwang
authors.forename: Hyuk Bang
authors.initials: HB
authors.lastname: Kwon
authors.forename: Nicolas
authors.initials: N
authors.lastname: Beaudet
authors.forename: Philippe
authors.initials: P
authors.lastname: Sarret
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Seong
mesh_terms: D000818:Animals; D002460:Cell Line; D006367:HeLa Cells; D006801:Humans; D025941:Protein Interaction Mapping; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D051381:Rats; D018028:Receptors, Neurotensin / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*
chemical_list: C490985:NTSR2 protein, human; D018028:Receptors, Neurotensin; C114036:neurotensin type 1 receptor