Characterization of G-Protein Coupled Receptor Kinase Interaction with the Neurokinin-1 Receptor Using Bioluminescence Resonance Energy Transfer

• Published in: Molecular pharmacology 2008-02, Vol.73 (2), p.349-358
• Main Authors: Jorgensen, Rasmus, Holliday, Nicholas D., Hansen, Jakob L., Vrecl, Milka, Heding, Anders, Schwartz, Thue W., Elling, Christian E.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Cell Line; Energy Transfer - physiology; G-Protein-Coupled Receptor Kinases - analysis; G-Protein-Coupled Receptor Kinases - metabolism; Humans; Luminescent Proteins - analysis; Luminescent Proteins - metabolism; Molecular Sequence Data; Protein Binding - physiology; Receptors, Neurokinin-1 - analysis; Receptors, Neurokinin-1 - metabolism; Renilla
• ISSN: 0026-895X; 1521-0111
• DOI: 10.1124/mol.107.038877

To analyze the interaction between the neurokinin-1 (NK-1) receptor and G-protein coupled receptor kinases (GRKs), we performed bioluminescence resonance energy transfer2 (BRET2) measurements between the family A NK-1 receptor and GRK2 and GRK5 as well as their respective kinase-inactive mutants. We observed agonist induced interaction of both GRK5 and GRK2 with the activated NK-1 receptor. In saturation experiments, we observed GRK5 to interact with the activated receptor in a monophasic manner while GRK2 interacted in a biphasic manner with the low affinity phase corresponding to receptor affinity for GRK5. Agonist induced GRK5 interaction with the receptor was dependent on intact kinase-activity, whereas the high affinity phase of GRK2 interaction was independent of kinase activity. We were surprised to find that the BRET2 saturation experiments indicated that before receptor activation, the full-length NK-1 receptor, but not a functional C-terminal tail-truncated receptor, is preassociated with GRK5 in a relatively low-affinity state. We demonstrate that GRK5 can compete for agonist induced GRK2 interaction with the NK-1 receptor, whereas GRK2 does not compete for receptor interaction with GRK5. We suggest that GRK5 is preassociated with the NK-1 receptor and that GRK5, rather than GRK2, is a key player in competitive regulation of GRK subtype specific interaction with the NK-1 receptor.