Pathway candidateNCBI-verifiedprotein-coding

ABCB9

ATP binding cassette subfamily B member 9

NCBI Gene: 23457 Ensembl GeneCards UniProt: Q9NP78

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

ABCB9 is in the library because it belongs to the drug transporters family. No study, report or commentary in the corpus names it, so a variant in ABCB9 is not, by itself, evidence of anything related to post-drug syndromes.

Gene summary

A protein-coding gene on chromosome 12 (drug and xenobiotic transporters). The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes.

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

Protein reference (UniProt)

Protein: ABC-type oligopeptide transporter ABCB9
Function: ATP-dependent low-affinity peptide transporter which translocates a broad spectrum of peptides from the cytosol to the lysosomal lumen for degradation. Displays a broad peptide length specificity from 6-mer up to at least 59-mer peptides with an optimum of 23-mers. Binds and transports smaller and larger peptides with the same affinity. Favors positively charged, aromatic or hydrophobic residues in the N- and C-terminal positions whereas negatively charged residues as well as asparagine and methionine are not favored.
Subcellular location: Lysosome membrane.
Tissue specificity: Highly expressed in testis, and at moderate levels in brain, spinal cord, and thyroid. Not expressed in monocytes but strongly expressed during differentiation of monocytes to dendritic cells and macrophages.

Source: UniProtKB/Swiss-Prot Q9NP78, 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

Transporters set systemic exposure to finasteride/SSRIs and clear conjugated steroid metabolites — directly relevant to both drug pharmacokinetics and Powers' clearance-centered PFS mechanism.

Written for the whole drug transporters family, not for ABCB9 specifically.

Mentioned in 0 corpus records

No corpus record names ABCB9 directly yet. It is in the library because it sits in a pathway the corpus tracks (Drug transporters).

Also in drug and xenobiotic transporters

All 62 genes

Browse by family on the gene families page.

Gene summary

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

Protein reference (UniProt)

Protein: ABC-type oligopeptide transporter ABCB9
Function: ATP-dependent low-affinity peptide transporter which translocates a broad spectrum of peptides from the cytosol to the lysosomal lumen for degradation. Displays a broad peptide length specificity from 6-mer up to at least 59-mer peptides with an optimum of 23-mers. Binds and transports smaller and larger peptides with the same affinity. Favors positively charged, aromatic or hydrophobic residues in the N- and C-terminal positions whereas negatively charged residues as well as asparagine and methionine are not favored.
Subcellular location: Lysosome membrane.
Tissue specificity: Highly expressed in testis, and at moderate levels in brain, spinal cord, and thyroid. Not expressed in monocytes but strongly expressed during differentiation of monocytes to dendritic cells and macrophages.