TCDB is operated by the Saier Lab Bioinformatics Group
« See all members of the family


1.A.9.2.3
The 5-hydroxytryptamine (serotonin) receptor-3A receptor/cation-selective ion channel, 5-HT3AR, of 454 aas.  The channel is activated by the binding of serotonin to an extracellular orthosteric site, located at the interface of two adjacent receptor subunits. A variety of compounds modulate agonist-evoked responses of 5-HT3ARs and other Cys-loop receptors by binding to distinct allosteric sites (Lansdell et al. 2014).  Alternative intersubunit pathways may exist for ion translocation at the interface between the extracellular and the transmembrane domains, in addition to the one along the channel main axis. An arginine triplet located in the intracellular domain may determine the characteristic low conductance properties of the channel (Di Maio et al. 2015). The 12 Å resolution structure of the protein in a lipid bilayer (cryo EM) reveals topological features (Kudryashev et al. 2016).  A  chimeric receptor consisting of the extracellular domain of the 5-HT3A receptor and the transmembrane domain of a prokaryotic homologue, ELIC has been constructed (Price and Lummis 2018). The resulting receptor responds to 5-HT. Partial agonists and competitive antagonists activate and inhibit the chimera. Examination of a range of receptor modulators including ethanol, thymol, 5-hydroxyindole, and 5-chloroindole suggest that these compounds act via the transmembrane domain, except for 5-hydroxyindole, which can compete with 5-HT at the orthosteric binding site (Price and Lummis 2018).

Accession Number:Q70Z44
Protein Name:5-hydroxytryptamine receptor 3D
Length:454
Molecular Weight:50191.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:4
Location1 / Topology2 / Orientation3: Cell membrane1 / Multi-pass membrane protein2
Substrate ions

Cross database links:

External Searches:

  • Search: DB with
  • BLAST ExPASy (Swiss Institute of Bioinformatics (SIB) BLAST)
  • CDD Search (Conserved Domain Database)
  • Search COGs (Clusters of Orthologous Groups of proteins)
  • 2° Structure (Network Protein Sequence Analysis)

Analyze:

Predict TMSs (Predict number of transmembrane segments)
Window Size: Angle:  
Window Size: Angle:  
FASTA formatted sequence
1:	MQKHSPGPPA LALLSQSLLT TGNGDTLIIN CPGFGQHRVD PAAFQAVFDR KAIGPVTNYS 
61:	VATHVNISFT LSAIWNCYSR IHTFNCHHAR PWHNQFVQWN PDECGGIKKS GMATENLWLS 
121:	DVFIEESVDQ TPAGLMASMS IVKATSNTIS QCGWSASANW TPSISPSMDR ARAWRRMSRS 
181:	FQIHHRTSFR TRREWVLLGI QKRTIKVTVA TNQYEQAIFH VAIRRRCRPS PYVVNFLVPS 
241:	GILIAIDALS FYLPLESGNC APFKMTVLLG YSVFLLMMND LLPATSTSSH ASLVAPLALM 
301:	QTPLPAGVYF ALCLSLMVGS LLETIFITHL LHVATTQPLP LPRWLHSLLL HCTGQGRCCP 
361:	TAPQKGNKGP GLTPTHLPGV KEPEVSAGQM PGPGEAELTG GSEWTRAQRE HEAQKQHSVE 
421:	LWVQFSHAMD ALLFRLYLLF MASSIITVIC LWNT