PIGW: Phosphatidylinositol Glycan Anchor Biosynthesis Class W
A key enzyme in GPI anchor biosynthesis, associated with inherited glycosylphosphatidylinositol (GPI) deficiency and developmental disorders.
Gene Information Card
| Symbol | PIGW |
|---|---|
| Full Name | Phosphatidylinositol Glycan Anchor Biosynthesis Class W |
| Gene Type | Protein coding |
| Chromosomal Location | 17q12 |
| NCBI Gene ID | 284098 ncbi.nlm.nih.gov/gene/284098 |
| Ensembl ID | ENSG00000178896 |
| UniProt ID | Q7Z7B1 |
| OMIM ID | 610137 |
| HGNC ID | 20213 |
| Aliases | GPI7, MGC26594 |
Description
PIGW encodes an inositol acyltransferase that catalyzes the second step of glycosylphosphatidylinositol (GPI) anchor biosynthesis, specifically the acylation of inositol. This modification is essential for the attachment of GPI anchors to proteins, which are critical for cell surface expression and function. Mutations in PIGW cause a form of inherited GPI deficiency (GPIBD11) characterized by intellectual disability, seizures, and facial dysmorphism.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Glycosylphosphatidylinositol Biosynthesis Defect 11 (GPIBD11) | Loss-of-function mutations impair GPI anchor synthesis, reducing cell surface GPI-anchored proteins. | OMIM #616025; ClinVar; multiple case reports (e.g., Chiyonobu et al., 2014) |
| Intellectual disability with seizures | Deficient GPI anchoring disrupts neuronal protein function, leading to neurodevelopmental phenotypes. | ClinVar; literature (e.g., Ng et al., 2012) |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.5 | Medium |
| Brain (cerebellum) | 8.2 | Low |
| Kidney | 7.1 | Low |
| Liver | 5.3 | Low |
| Heart | 4.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 10.2 | Embryonic kidney cells |
| K562 | 6.5 | Leukemia cells |
| HepG2 | 5.9 | Liver cancer cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.263A>G (p.Tyr88Cys) | Missense | Rare | Loss of function; reduced GPI-AP expression |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of function; no protein product |
| c.256C>T (p.Arg86Trp) | Missense | Rare | Loss of function; impaired enzyme activity |
Mutation functional classification
Loss of Function (LOF)
Most reported PIGW mutations are loss-of-function, leading to reduced GPI anchor synthesis and decreased cell surface GPI-anchored proteins.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • membrane (GO:0016020) | • GPI anchor biosynthetic process (GO:0006506) |
| • acyltransferase activity (GO:0016746) | • inositol acylation (GO:0008375) |
Pathways
• GPI anchor biosynthesis (KEGG: hsa00563)
• Metabolism of GPI-anchored proteins (Reactome: R-HSA-162710)
Protein Summary
PIGW is a 504-amino acid transmembrane protein localized to the endoplasmic reticulum. It functions as an inositol acyltransferase, adding a palmitoyl group to inositol during GPI anchor synthesis. This modification is required for subsequent steps of GPI anchor assembly. Defects in PIGW lead to incomplete GPI anchors and reduced cell surface expression of GPI-anchored proteins, particularly affecting neural development.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PIGW Knockout HEK293 Cell Line | EDJ-KQ14763 | Human | 284098 | Details Get a Quote |
| PIGW Knockout A-549 Cell Line | EDJ-KQ45157 | Human | 284098 | Details Get a Quote |
| PIGW Knockout HCT 116 Cell Line | EDJ-KQ45158 | Human | 284098 | Details Get a Quote |
| PIGW Knockout HeLa Cell Line | EDJ-KQ45159 | Human | 284098 | Details Get a Quote |
