Pathway candidateNCBI-verifiedprotein-coding

HTR4

5-hydroxytryptamine receptor 4

NCBI Gene: 3360 Ensembl GeneCards UniProt: Q13639

Pathway candidate — not linked to PFS or PSSD by any record here

HTR4 is in the library because it belongs to the neurotransmission family. No study, report or commentary in the corpus names it, so a variant in HTR4 is not, by itself, evidence of anything related to post-drug syndromes.

Gene summary

A protein-coding gene on chromosome 5 (neurotransmission). This gene is a member of the family of serotonin receptors, which are G protein coupled receptors that stimulate cAMP production in response to serotonin (5-hydroxytryptamine). The gene product is a glycosylated transmembrane protein that functions in both the peripheral and central nervous system to modulate the release of various neurotransmitters.

Source: NCBI Gene, accessed 2026-10-07.

Protein reference (UniProt)

Protein: 5-hydroxytryptamine receptor 4
Function: G protein-coupled receptor for 5-hydroxytryptamine (serotonin), a biogenic hormone that functions as a neurotransmitter, a hormone and a mitogen. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of downstream effectors. HTR4 is coupled to G(s) G alpha proteins and mediates activation of adenylate cyclase activity.
Subcellular location: Cell membrane; Endosome membrane.
Tissue specificity: Isoform 5-HT4(A): Expressed in ileum, brain, and atrium, but not in the ventricle. Isoform 5-HT4(E): Mainly expressed in atria and cardiac ventricle. Isoform 5-HT4(I): Expressed in all cardiovascular tissues analyzed.

Source: UniProtKB/Swiss-Prot Q13639, release 2026_03, licensed CC BY 4.0. This is the protein’s normal biology, not evidence about post-drug syndromes; associated conditions are inherited disorders of the gene, not PFS, PSSD or PRSD.

Why its pathway is in the library

Monoamine, GABA, glutamate, and cholinergic systems are the direct pharmacologic targets of SSRIs/SNRIs (PSSD) and the downstream effectors of neurosteroid signaling (PFS).

Written for the whole neurotransmission family, not for HTR4 specifically.

Mentioned in 0 corpus records

No corpus record names HTR4 directly yet. It is in the library because it sits in a pathway the corpus tracks (Neurotransmission).

Also in neurotransmission

All 54 genes

Browse by family on the gene families page.

Gene summary

Source: NCBI Gene, accessed 2026-10-07.

Protein reference (UniProt)

Protein: 5-hydroxytryptamine receptor 4
Function: G protein-coupled receptor for 5-hydroxytryptamine (serotonin), a biogenic hormone that functions as a neurotransmitter, a hormone and a mitogen. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of downstream effectors. HTR4 is coupled to G(s) G alpha proteins and mediates activation of adenylate cyclase activity.
Subcellular location: Cell membrane; Endosome membrane.
Tissue specificity: Isoform 5-HT4(A): Expressed in ileum, brain, and atrium, but not in the ventricle. Isoform 5-HT4(E): Mainly expressed in atria and cardiac ventricle. Isoform 5-HT4(I): Expressed in all cardiovascular tissues analyzed.