title: Identification and functional characterisation of 5-HT4 receptor in sea cucumber Apostichopus japonicus (Selenka).
abstract: Serotonin (5-HT) is an important neurotransmitter and neuromodulator that controls a variety of sensory and motor functions through 5-HT receptors (5-HTRs). The 5-HT4R subfamily is linked to Gs proteins, which activate adenylyl cyclases (ACs), and is involved in many responses in peripheral organs. In this study, the 5-HT4R from Apostichopus japonicus (Aj5-HT4R) was identified and characterised. The cloned full-length Aj5-HT4R cDNA is 1,544 bp long and contains an open reading frame 1,011 bp in length encoding 336 amino acid proteins. Bioinformatics analysis of the Aj5-HT4R protein indicated this receptor was a member of class A G protein coupled receptor (GPCR) family. Further experiments using Aj5-HT4R-transfected HEK293 cells demonstrated that treatment with 5-HT triggered a significant increase in intracellular cAMP level in a dose-dependent manner and induced a rapid internalisation of Aj5-HT4R fused with enhanced green fluorescent protein (Aj5-HT4R-EGFP) from the cell surface into the cytoplasm. In addition, the transcriptional profiles of Aj5-HT4R in aestivating A. japonicas and phosphofructokinase (AjPFK) in 5-HT administrated A. japonicus have been analysed by real-time PCR assays. Results have led to a basic understanding of Aj5-HT4R in A. japonicus, and provide a foundation for further exploration of the cell signaling and regulatory functions of this receptor.
authors.affiliation: National Engineering Research Center of Marine Facilities Aquaculture, Marine Science College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China.
authors.forename: Tianming
authors.initials: T
authors.lastname: Wang
authors.affiliation: National Engineering Research Center of Marine Facilities Aquaculture, Marine Science College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Institute of Biochemistry, College of LifeSciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China.
authors.forename: Naiming
authors.initials: N
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong 266071, People's Republic of China.
authors.forename: Lina
authors.initials: L
authors.lastname: Sun
authors.affiliation: National Engineering Research Center of Marine Facilities Aquaculture, Marine Science College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China.
authors.forename: Zhenming
authors.initials: Z
authors.lastname: Lv
authors.affiliation: National Engineering Research Center of Marine Facilities Aquaculture, Marine Science College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China.
authors.forename: Changwen
authors.initials: C
authors.lastname: Wu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D057809:HEK293 Cells; D006801:Humans; D012333:RNA, Messenger / Q000378:metabolism; D044422:Receptors, Serotonin, 5-HT4 / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D047528:Stichopus / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D044422:Receptors, Serotonin, 5-HT4; D000242:Cyclic AMP