Pathway candidateNCBI-verifiedprotein-coding

NPC1

NPC intracellular cholesterol transporter 1

NCBI Gene: 4864 Ensembl GeneCards UniProt: O15118

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

NPC1 is in the library because it belongs to the lipid homeostasis family. No study, report or commentary in the corpus names it, so a variant in NPC1 is not, by itself, evidence of anything related to post-drug syndromes.

Gene summary

A protein-coding gene on chromosome 18 (lipid and cholesterol homeostasis). Encodes a large protein that resides in the limiting membrane of endosomes and lysosomes and mediates intracellular cholesterol trafficking via binding of cholesterol to its N-terminal domain. It is predicted to have a cytoplasmic C-terminus, 13 transmembrane domains, and 3 large loops in the lumen of the endosome - the last loop being at the N-terminus.

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

Protein reference (UniProt)

Protein: NPC intracellular cholesterol transporter 1
Function: Intracellular cholesterol transporter which acts in concert with NPC2 and plays an important role in the egress of cholesterol from the endosomal/lysosomal compartment. Unesterified cholesterol that has been released from LDLs in the lumen of the late endosomes/lysosomes is transferred by NPC2 to the cholesterol-binding pocket in the N-terminal domain of NPC1. Cholesterol binds to NPC1 with the hydroxyl group buried in the binding pocket. Mediates cholesterol transfer from lysosomes to endoplasmic reticulum by tethering endosomal/lysosomal compartments and endoplasmic reticulum membrane contact sites where it interacts with sterol transport protein GRAMD1B. Binds oxysterol with higher affinity than cholesterol. May play a role in vesicular trafficking in glia, a process that may be crucial for maintaining the structural and functional integrity of nerve terminals (Probable). Inhibits cholesterol-mediated mTORC1 activation throught its interaction with SLC38A9.
Subcellular location: Late endosome membrane; Lysosome membrane.
Associated conditions: Niemann-Pick disease C1 (NPC1).

Source: UniProtKB/Swiss-Prot O15118, 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

Cholesterol is the obligate precursor of all steroid hormones; lipid handling sets substrate supply for steroidogenesis and neurosteroid synthesis.

Written for the whole lipid homeostasis family, not for NPC1 specifically.

Mentioned in 0 corpus records

No corpus record names NPC1 directly yet. It is in the library because it sits in a pathway the corpus tracks (Lipid homeostasis).

Also in lipid and cholesterol homeostasis

All 19 genes

Browse by family on the gene families page.

Gene summary

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

Protein reference (UniProt)

Protein: NPC intracellular cholesterol transporter 1
Function: Intracellular cholesterol transporter which acts in concert with NPC2 and plays an important role in the egress of cholesterol from the endosomal/lysosomal compartment. Unesterified cholesterol that has been released from LDLs in the lumen of the late endosomes/lysosomes is transferred by NPC2 to the cholesterol-binding pocket in the N-terminal domain of NPC1. Cholesterol binds to NPC1 with the hydroxyl group buried in the binding pocket. Mediates cholesterol transfer from lysosomes to endoplasmic reticulum by tethering endosomal/lysosomal compartments and endoplasmic reticulum membrane contact sites where it interacts with sterol transport protein GRAMD1B. Binds oxysterol with higher affinity than cholesterol. May play a role in vesicular trafficking in glia, a process that may be crucial for maintaining the structural and functional integrity of nerve terminals (Probable). Inhibits cholesterol-mediated mTORC1 activation throught its interaction with SLC38A9.
Subcellular location: Late endosome membrane; Lysosome membrane.
Associated conditions: Niemann-Pick disease C1 (NPC1).