Seroatlas · Human Serome Atlas

PLAC9

Placenta-specific protein 9

Also known as: PLAC9_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q5JTB6
Gene
PLAC9
Ensembl
ENSG00000189129
Chromosome
10
Canonical length
97 aa
Protein class
Predicted intracellular proteins, Predicted secreted proteins
Secretome location
Secreted - unknown location

OverviewNCBI Gene

Predicted to be located in extracellular region. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

97 residues, UniProt reviewed canonical sequence.

>Q5JTB6|PLAC9
     1  MRPLLCALTG LALLRAAGSL AAAEPFSPPR GDSAQSTACD RHMAVQRRLD VMEEMVEKTV
    61  DHLGTEVKGL LGLLEELAWN LPPGPFSPAP DLLGDGF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PLAC9 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
Secreted
Secreted
Yes
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.57
Highest tissue expression
216 nTPM

Expression across tissuesHPA

Tissue

  • choroid plexus: 216 nTPM
  • blood vessel: 134 nTPM
  • heart muscle: 124 nTPM
  • adipose tissue: 109 nTPM
  • breast: 85 nTPM
  • vagina: 76 nTPM

Single-cell type

  • leydig cells: 782 nCPM
  • fibroblasts: 635 nCPM
  • peritubular myoid cells: 617 nCPM
  • retinal pigment epithelial cells: 541 nCPM
  • vascular smooth muscle cells: 424 nCPM
  • pericytes: 299 nCPM

Immune cell

  • eosinophil: 1 nTPM
  • neutrophil: 0.5 nTPM
  • MAIT T-cell: 0.1 nTPM
  • memory CD8 T-cell: 0.1 nTPM
  • plasmacytoid DC: 0.1 nTPM
  • T-reg: 0.1 nTPM

Brain region

  • choroid plexus: 104 nTPM
  • cerebral cortex: 25 nTPM
  • hippocampal formation: 23 nTPM
  • cerebellum: 14 nTPM
  • amygdala: 14 nTPM
  • basal ganglia: 12 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)
1.69
gnomAD pLI
0
gnomAD missense Z
-0.18
DepMap mean gene effect
-0.19
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Cellular components

Protein domainsUniProt · Pfam · InterPro

  • Placenta-specific protein 9
  • Placenta-specific protein 9

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads PLAC9 as an antibody target. Whether an autoantibody or antibody against PLAC9 could matter depends on whether native PLAC9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PLAC9 is annotated as secreted, so native PLAC9 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label PLAC9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PLAC9. 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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