Heterodimerization of human apelin and kappa opioid receptors: roles in signal transduction.
Apelin receptor (APJ) and kappa opioid receptor (KOR) are members of the family A of G protein-coupled receptors (GPCRs). These two receptors are involved in the central nervous system regulation of the cardiovascular system. Here, we explore the possibility of heterodimerization between APJ and KOR and investigate their novel signal transduction characteristics. Co-immunoprecipitation (Co-IP), co-localization and bioluminescence resonance energy transfer (BRET) assays confirmed the heterodimerization of APJ and KOR. In APJ and KOR stably transfected HEK293 cells, treatment with APJ ligand apelin-13 or KOR ligand dynorphinA (1-13) resulted in higher phosphorylation levels of extracellular-regulated kinases 1/2 (ERK1/2) compared to HEK293 cells transfected with either APJ or KOR alone. The siRNA knockdown of either APJ or KOR receptor in human umbilical vein endothelial cells (HUVECs) resulted in significant reduction of the apelin-13 induced ERK activation. Additionally both forskolin (FSK)-induced cAMP levels and cAMP response element reporter activities were significantly reduced, whereas the serum response element luciferase (SRE-luc) reporter activity was significantly upregulated. Moreover, the ERK phosphorylation and SRE-luc activity were abrogated by the protein kinase C (PKC) inhibitor. These results demonstrate for the first time that human APJ forms a heterodimer with KOR and leads to increased PKC and decreased protein kinase A activity leading to a significant increase in cell proliferation, which may translate to the regulation of diverse biological actions and offers the potential for the development of more selective and tissue specific drug therapies.
School of life science, Shandong Agricultural University, Taian, 271018, China. tsmclyl@126.com
Yalin
Y
Li
Jing
J
Chen
Bo
B
Bai
Hui
H
Du
Youwang
Y
Liu
Haiqing
H
Liu
D000073861:Apelin; D049109:Cell Proliferation; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004399:Dynorphins / Q000378:metabolism / Q000502:physiology; D004789:Enzyme Activation; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism / Q000502:physiology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism / Q000502:physiology*; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D055503:Protein Multimerization; D017473:Receptors, Opioid, kappa / Q000378:metabolism*; D015398:Signal Transduction
C115436:APLN protein, human; D000073861:Apelin; D036341:Intercellular Signaling Peptides and Proteins; D017473:Receptors, Opioid, kappa; D005576:Colforsin; D004399:Dynorphins; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3