PT  - JOURNAL ARTICLE
AU  - Jorgensen, Rasmus
AU  - Holliday, Nicholas D.
AU  - Hansen, Jakob L.
AU  - Vrecl, Milka
AU  - Heding, Anders
AU  - Schwartz, Thue W.
AU  - Elling, Christian E.
TI  - Characterization of G-Protein Coupled Receptor Kinase Interaction with the Neurokinin-1 Receptor Using Bioluminescence Resonance Energy Transfer
AID  - 10.1124/mol.107.038877
DP  - 2008 Feb 01
TA  - Molecular Pharmacology
PG  - 349--358
VI  - 73
IP  - 2
4099  - http://molpharm.aspetjournals.org/content/73/2/349.short
4100  - http://molpharm.aspetjournals.org/content/73/2/349.full
SO  - Mol Pharmacol2008 Feb 01; 73
AB  - 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. The American Society for Pharmacology and Experimental Therapeutics