Seroatlas · Human Serome Atlas

SIGLEC9

Sialic acid-binding Ig-like lectin 9

Also known as: CD329, SIGL9_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9Y336
Gene
SIGLEC9
Ensembl
ENSG00000129450
Chromosome
19
Canonical length
463 aa
Protein class
Predicted membrane proteins

OverviewNCBI Gene

Predicted to enable monosaccharide binding activity and sialic acid binding activity. Predicted to be involved in cell adhesion. Predicted to act upstream of or within negative regulation of inflammatory response and negative regulation of phagocytosis, engulfment. Predicted to be located in external side of plasma membrane. Predicted to be active in plasma membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

463 residues, UniProt reviewed canonical sequence.

>Q9Y336|SIGLEC9
     1  MLLLLLPLLW GRERAEGQTS KLLTMQSSVT VQEGLCVHVP CSFSYPSHGW IYPGPVVHGY
    61  WFREGANTDQ DAPVATNNPA RAVWEETRDR FHLLGDPHTK NCTLSIRDAR RSDAGRYFFR
   121  MEKGSIKWNY KHHRLSVNVT ALTHRPNILI PGTLESGCPQ NLTCSVPWAC EQGTPPMISW
   181  IGTSVSPLDP STTRSSVLTL IPQPQDHGTS LTCQVTFPGA SVTTNKTVHL NVSYPPQNLT
   241  MTVFQGDGTV STVLGNGSSL SLPEGQSLRL VCAVDAVDSN PPARLSLSWR GLTLCPSQPS
   301  NPGVLELPWV HLRDAAEFTC RAQNPLGSQQ VYLNVSLQSK ATSGVTQGVV GGAGATALVF
   361  LSFCVIFVVV RSCRKKSARP AAGVGDTGIE DANAVRGSAS QGPLTEPWAE DSPPDQPPPA
   421  SARSSVGEGE LQYASLSFQM VKPWDSRGQE ATDTEYSEIK IHR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SIGLEC9 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
Cell surface
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.42
Highest tissue expression
20 nTPM

Expression across tissuesHPA

Tissue

  • spleen: 20 nTPM
  • appendix: 17 nTPM
  • bone marrow: 8.5 nTPM
  • lung: 7.8 nTPM
  • adipose tissue: 7.5 nTPM
  • placenta: 7.4 nTPM

Single-cell type

  • neutrophils: 227 nCPM
  • monocytes: 93 nCPM
  • kupffer cells: 86 nCPM
  • hofbauer cells: 60 nCPM
  • macrophages: 46 nCPM
  • monocyte progenitors: 39 nCPM

Immune cell

  • neutrophil: 213 nTPM
  • classical monocyte: 199 nTPM
  • intermediate monocyte: 183 nTPM
  • myeloid DC: 169 nTPM
  • non-classical monocyte: 122 nTPM
  • total PBMC: 85 nTPM

Brain region

  • thalamus: 14 nTPM
  • white matter: 13 nTPM
  • medulla oblongata: 12 nTPM
  • pons: 11 nTPM
  • spinal cord: 8.8 nTPM
  • cerebral cortex: 8.5 nTPM

ReferencesPubMed · IEDB

Publications for SIGLEC9 from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Reference: AutoantibodyPubMed

3 publications

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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)
0.97
gnomAD pLI
0
gnomAD missense Z
0.61
DepMap mean gene effect
0.02
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SIGLEC9 as an antibody target. Whether an autoantibody or antibody against SIGLEC9 could matter depends on whether native SIGLEC9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SIGLEC9 is annotated at the cell surface, where native SIGLEC9 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label SIGLEC9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SIGLEC9. 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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