Seroatlas · Human Serome Atlas

PIGX

GPI alpha-1,4-mannosyltransferase I, stabilizing subunit

Also known as: FLJ20522, PIGX_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
Q8TBF5
Gene
PIGX
Ensembl
ENSG00000163964
Chromosome
3
Canonical length
258 aa
Protein class
Metabolic proteins, Predicted intracellular proteins, Predicted membrane proteins
Subcellular location
Nucleoplasm,Plasma membrane,Cytosol

OverviewNCBI Gene

This gene encodes a type I transmembrane protein in the endoplasmic reticulum (ER). The protein is an essential component of glycosylphosphatidylinositol-mannosyltransferase I, which transfers the first of the four mannoses in the GPI-anchor precursors during GPI-anchor biosynthesis. Studies in rat indicate that the protein is translated from a non-AUG translation initiation site. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2009]

Canonical amino-acid sequenceUniProt

258 residues, UniProt reviewed canonical sequence.

>Q8TBF5|PIGX
     1  MAARVAAVRA AAWLLLGAAT GLTRGPAAAF TAARSDAGIR AMCSEIILRQ EVLKDGFHRD
    61  LLIKVKFGES IEDLHTCRLL IKQDIPAGLY VDPYELASLR ERNITEAVMV SENFDIEAPN
   121  YLSKESEVLI YARRDSQCID CFQAFLPVHC RYHRPHSEDG EASIVVNNPD LLMFCDQEFP
   181  ILKCWAHSEV AAPCALENED ICQWNKMKYK SVYKNVILQV PVGLTVHTSL VCSVTLLITI
   241  LCSTLILVAV FKYGHFSL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PIGX can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Other membrane
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.39
Highest tissue expression
20 nTPM

Expression across tissuesHPA

Tissue

  • choroid plexus: 20 nTPM
  • cerebral cortex: 19 nTPM
  • parathyroid gland: 18 nTPM
  • basal ganglia: 18 nTPM
  • hypothalamus: 18 nTPM
  • midbrain: 18 nTPM

Single-cell type

  • neutrophils: 81 nCPM
  • mast cells: 78 nCPM
  • megakaryocyte-erythroid progenitors: 78 nCPM
  • esophageal basal cells: 68 nCPM
  • megakaryocyte progenitors: 67 nCPM
  • hematopoietic stem cells: 66 nCPM

Immune cell

  • eosinophil: 88 nTPM
  • basophil: 40 nTPM
  • neutrophil: 19 nTPM
  • non-classical monocyte: 12 nTPM
  • intermediate monocyte: 11 nTPM
  • NK-cell: 8.7 nTPM

Brain region

  • choroid plexus: 29 nTPM
  • hypothalamus: 23 nTPM
  • white matter: 22 nTPM
  • spinal cord: 21 nTPM
  • midbrain: 21 nTPM
  • thalamus: 21 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.16
gnomAD pLI
0
gnomAD missense Z
1.16
DepMap mean gene effect
0
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 13% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Cellular components

Protein domainsUniProt · Pfam · InterPro

  • Glycosylphosphatidylinositol-mannosyltransferase I, PIG-X/PBN1
  • Phosphatidylinositol-glycan biosynthesis class X protein
  • PIG-X / PBN1

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of PIGX in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads PIGX as an antibody target. Whether an autoantibody or antibody against PIGX could matter depends on whether native PIGX is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PIGX is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label PIGX as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PIGX. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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