Physical interaction of Jab1 with human serotonin 6 G-protein-coupled receptor and their possible roles in cell survival.
The 5-HT(6) receptor (5-HT(6)R) is one of the most recently cloned serotonin receptors, and it plays important roles in Alzheimer disease, depression, and learning and memory disorders. However, unlike the other serotonin receptors, the cellular mechanisms of 5-HT(6)R are poorly elucidated relative to its significance in human brain diseases. Here, using a yeast two-hybrid assay, we found that the human 5-HT(6)R interacts with Jun activation domain-binding protein-1 (Jab1). We also confirmed a physical interaction between 5-HT(6)R and Jab1 using glutathione S-transferase pulldown, fluorescence resonance energy transfer, co-immunoprecipitation, and immunocyto(histo)chemistry assays. The manipulation of Jab1 expression using Jab1 small interference RNA decreased 5-HT(6)R-mediated activity and cell membrane expression of 5-HT(6)R, whereas overexpression of Jab1 produced no significant effect. In addition, we demonstrated that the activation of 5-HT(6)R induced the translocation of Jab1 into the nucleus and increased c-Jun phosphorylation and the interaction between Jab1 and c-Jun. Furthermore, we found that 5-HT(6)R and Jab1 were up-regulated in middle cerebral artery occlusion-induced focal cerebral ischemic rats and in cultured cells exposed to hypoxic insults, suggesting possible protective roles for 5-HT(6)R and Jab1. These findings suggest that Jab1 provides a novel signal transduction pathway for 5-HT(6)R and may play an important role in 5-HT(6)R-mediated behavior changes in the brain.
Yun
Hyung-Mun
HM
Life Sciences Division, Korea Institute of Science and Technology, Seoul 136-791; School of Life Sciences and Biotechnology, Korea University, Seoul 136-701.
Baik
Ja-Hyun
JH
School of Life Sciences and Biotechnology, Korea University, Seoul 136-701.
Kang
Insug
I
College of Medicine, KyungHee University, Seoul 130-702.
Jin
Changbae
C
Doping Control Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
Rhim
Hyewhon
H
Life Sciences Division, Korea Institute of Science and Technology, Seoul 136-791. Electronic address: hrhim@kist.re.kr.
D000818:Animals; D001921:Brain / Q000378:metabolism; D001927:Brain Diseases / Q000378:metabolism; D016466:CHO Cells; D000075686:COP9 Signalosome Complex; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D006224:Cricetinae; D003412:Cricetulus; D005786:Gene Expression Regulation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D007511:Ischemia / Q000473:pathology; D010447:Peptide Hydrolases / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry*; D011985:Receptors, Serotonin / Q000737:chemistry*
D047908:Intracellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled; D011985:Receptors, Serotonin; C097216:serotonin 6 receptor; D010447:Peptide Hydrolases; C501488:COPS5 protein, human; D000075686:COP9 Signalosome Complex