OCBIM_22008529mg (SLC6A4 / SERT) - Review Notes

Gene Identity

• UniProt: A0A0L8FU48 (unreviewed TrEMBL entry)
• Gene model: OCBIM_22008529mg from O. bimaculoides genome PMID:26268193
• Protein: Sodium-dependent serotonin transporter (507 AA)
• PANTHER family: PTHR11616 (Sodium/chloride dependent transporter)
• PANTHER subfamily: PTHR11616:SF279 (Sodium-dependent serotonin transporter)
• InterPro: IPR000175 (Na/ntran_symport)
• Pfam: PF00209 (SNF - Sodium:neurotransmitter symporter family)

Key Literature

Edsinger & Dolen 2018 (PMID:30245101)

"A Conserved Role for Serotonergic Neurotransmission in Mediating Social Behavior in Octopus"
- Landmark paper demonstrating MDMA induces prosocial behavior in O. bimaculoides
- Identified the octopus SERT gene (Slc6A4) in the genome and showed conservation of MDMA binding site
- "MDMA enhances acute prosocial behaviors in Octopus bimaculoides"
- "the evolutionary conservation of the serotonin transporter (SERT, encoded by the Slc6A4 gene) binding site of MDMA in the O. bimaculoides genome"
- Octopuses on MDMA spent more time near social stimulus, exhibited tactile exploration
- Three-chambered social approach task paradigm used

Albertin et al. 2015 (PMID:26268193)

"The octopus genome and the evolution of cephalopod neural and morphological novelties"
- Source of the O. bimaculoides genome assembly containing OCBIM_22008529mg gene model
- 2.7 Gb genome with ~33,000 protein-coding genes

Protein Features (from UniProt)

• Signal peptide: 1-17
• 10 transmembrane helices predicted (Phobius)
• Na+ binding sites at positions 214, 246, 311, 314
• Disulfide bond: C77-C86
• Keywords: membrane, sodium, transport, metal-binding

GO Annotations from UniProt (not in QuickGO GOA)

The GOA TSV is empty, but UniProt DR lines list IEA/TreeGrafter annotations:
- GO:0043005 neuron projection (C, IEA:TreeGrafter)
- GO:0005886 plasma membrane (C, IEA:TreeGrafter)
- GO:0098793 presynapse (C, IEA:GOC)
- GO:0046872 metal ion binding (F, IEA:UniProtKB-KW)
- GO:0051378 serotonin binding (F, IEA:TreeGrafter)
- GO:0005335 serotonin:sodium:chloride symporter activity (F, IEA:TreeGrafter)
- GO:0006865 amino acid transport (P, IEA:TreeGrafter)

Deep Research Status

• OpenAI deep research failed (template variable error)
• Falcon deep research failed (template variable error)
• Manual research conducted via PubMed MCP

Cephalopod Serotonin Context

Based on PubMed searches for "cephalopod serotonin behavior":
- Serotonin is present in cephalopod nervous systems and plays roles in learning/memory (PMID:35107842)
- 5-HT modulates synaptic plasticity in the octopus vertical lobe (learning/memory center)
- Antidepressants (SSRIs like fluoxetine) affect behavior in cuttlefish (PMID:31610357)
- Serotonin is an evolutionarily ancient neurotransmitter system