OR6F1

Model summary

A human seven-helix chemosensory receptor that detects extracellular odorant molecules and converts their binding into intracellular signaling through heterotrimeric G proteins. Embedded in the plasma membrane as a multi-pass protein, it uses a rhodopsin-like transmembrane core to stabilize active conformations that recruit and activate G proteins, triggering second-messenger pathways that drive neuronal responses underlying smell. Its mechanism centers on ligand-triggered conformational changes within the seven-helix bundle that enable efficient signal initiation and termination at the cell surface.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture.

   The core transmembrane engine is IPR017452 (GPCR, rhodopsin-like, 7TM domain, residues 41–290), which encodes the canonical seven-helix bundle that transduces extracellular ligand binding into intracellular G protein activation. This structural core is embedded within multiple rhodopsin-like GPCR family signatures: IPR000276 (G protein-coupled receptor, rhodopsin-like family) appears in several positions—[26–50], [59–80], [104–126], [199–222], and [272–298]—marking conserved motifs across the N-terminus and intracellular loops that coordinate G protein coupling and arrestin interactions. Two olfactory-focused family signatures, IPR000725 (Olfactory receptor family, residues 31–303) and IPR047132 (Olfactory receptor subfamily 6C-like, residues 5–305), specify that this rhodopsin-like scaffold is tuned for odorant recognition and olfactory signaling. The ordered layout—an N-terminal extracellular region feeding into a 7TM bundle and intracellular loop network—causes ligand-triggered conformational switching that recruits heterotrimeric G proteins.

2. 02

   From this architecture, the molecular function resolves as a GPCR that binds protein partners to transmit signals.

   The rhodopsin-like 7TM fold and olfactory receptor family membership together enforce a mechanism in which extracellular odorant binding stabilizes an active state that binds and activates heterotrimeric G proteins; this supports GO:0005515 protein binding by necessitating direct coupling to Gα/βγ and regulatory adaptors.

3. 03

   This GPCR-driven activation propagates intracellular cascades, placing the protein squarely in GO:0007165 signal transduction.

   Because the receptor is an olfactory-type GPCR specialized for volatile ligand detection, its activity initiates the sensory pathway formalized as GO:0007606 sensory perception of chemical stimulus. The causal chain is: odorant binding in the extracellular pocket triggers helix rearrangements in the 7TM core, which in turn catalyze GDP-GTP exchange on Gα and launch second-messenger production.

4. 04

   Cellular location follows directly from the 7TM architecture and olfactory receptor identity.

   The multi-pass topology and signal initiation require residence in the plasma membrane, aligning with GO:0005886 plasma membrane and the experimentally grounded description as a cell-membrane, multi-pass protein. The absence of soluble domains and the presence of multiple membrane-spanning helices reinforce this membrane-embedded operational site.

5. 05

   Mechanistically, I hypothesize that the receptor resides in olfactory neuron membranes where it binds odorants via a hydrophobic pocket formed by the 7TM bundle.

   Ligand-induced rearrangements expose intracellular surfaces that capture olfactory-enriched G proteins (e.g., Gαolf), initiating cAMP signaling that opens cyclic nucleotide-gated channels and converts chemical cues into electrical signals. Likely interaction partners include Gαolf (GNAL), Gβ and Gγ subunits, receptor-transporting proteins that chaperone trafficking to the membrane, and arrestin/GRK modules that terminate signaling. Together, these interactions define a membrane-localized signal transducer that converts extracellular odorant occupancy into intracellular second-messenger waves and neuronal responses.