Seroatlas · Human Serome Atlas

IGSF9

Protein turtle homolog A

Also known as: IGSF9A, KIAA1355, Nrt1, TUTLA_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9P2J2
Gene
IGSF9
Ensembl
ENSG00000085552
Chromosome
1
Canonical length
1179 aa
Protein class
Predicted membrane proteins

OverviewNCBI Gene

Predicted to enable cell-cell adhesion mediator activity. Predicted to be involved in axon guidance; dendrite self-avoidance; and homophilic cell adhesion via plasma membrane adhesion molecules. Predicted to act upstream of or within dendrite development and regulation of synapse organization. Predicted to be located in dendrite and inhibitory synapse. Predicted to be active in axon; glutamatergic synapse; and postsynaptic density membrane. [provided by Alliance of Genome Resources, Apr 2025]

Canonical amino-acid sequenceUniProt

1179 residues, UniProt reviewed canonical sequence.

>Q9P2J2|IGSF9
     1  MVWCLGLAVL SLVISQGADG RGKPEVVSVV GRAGESVVLG CDLLPPAGRP PLHVIEWLRF
    61  GFLLPIFIQF GLYSPRIDPD YVGRVRLQKG ASLQIEGLRV EDQGWYECRV FFLDQHIPED
   121  DFANGSWVHL TVNSPPQFQE TPPAVLEVQE LEPVTLRCVA RGSPLPHVTW KLRGKDLGQG
   181  QGQVQVQNGT LRIRRVERGS SGVYTCQASS TEGSATHATQ LLVLGPPVIV VPPKNSTVNA
   241  SQDVSLACHA EAYPANLTYS WFQDNINVFH ISRLQPRVRI LVDGSLRLLA TQPDDAGCYT
   301  CVPSNGLLHP PSASAYLTVL YPAQVTAMPP ETPLPIGMPG VIRCPVRANP PLLFVSWTKD
   361  GKALQLDKFP GWSQGTEGSL IIALGNEDAL GEYSCTPYNS LGTAGPSPVT RVLLKAPPAF
   421  IERPKEEYFQ EVGRELLIPC SAQGDPPPVV SWTKVGRGLQ GQAQVDSNSS LILRPLTKEA
   481  HGHWECSASN AVARVATSTN VYVLGTSPHV VTNVSVVALP KGANVSWEPG FDGGYLQRFS
   541  VWYTPLAKRP DRMHHDWVSL AVPVGAAHLL VPGLQPHTQY QFSVLAQNKL GSGPFSEIVL
   601  SAPEGLPTTP AAPGLPPTEI PPPLSPPRGL VAVRTPRGVL LHWDPPELVP KRLDGYVLEG
   661  RQGSQGWEVL DPAVAGTETE LLVPGLIKDV LYEFRLVAFA GSFVSDPSNT ANVSTSGLEV
   721  YPSRTQLPGL LPQPVLAGVV GGVCFLGVAV LVSILAGCLL NRRRAARRRR KRLRQDPPLI
   781  FSPTGKSAAP SALGSGSPDS VAKLKLQGSP VPSLRQSLLW GDPAGTPSPH PDPPSSRGPL
   841  PLEPICRGPD GRFVMGPTVA APQERSGREQ AEPRTPAQRL ARSFDCSSSS PSGAPQPLCI
   901  EDISPVAPPP AAPPSPLPGP GPLLQYLSLP FFREMNVDGD WPPLEEPSPA APPDYMDTRR
   961  CPTSSFLRSP ETPPVSPRES LPGAVVGAGA TAEPPYTALA DWTLRERLLP GLLPAAPRGS
  1021  LTSQSSGRGS ASFLRPPSTA PSAGGSYLSP APGDTSSWAS GPERWPRREH VVTVSKRRNT
  1081  SVDENYEWDS EFPGDMELLE TLHLGLASSR LRPEAEPELG VKTPEEGCLL NTAHVTGPEA
  1141  RCAALREEFL AFRRRRDATR ARLPAYRQPV PHPEQATLL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against IGSF9 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)
0.48
Highest tissue expression
26 nTPM

Expression across tissuesHPA

Tissue

  • retina: 26 nTPM
  • liver: 26 nTPM
  • skin: 22 nTPM
  • stomach: 12 nTPM
  • small intestine: 9 nTPM
  • esophagus: 8.8 nTPM

Single-cell type

  • rod photoreceptor cells: 121 nCPM
  • foveolar cells: 81 nCPM
  • colonocytes: 62 nCPM
  • early spermatids: 53 nCPM
  • cone photoreceptor cells: 50 nCPM
  • late spermatids: 45 nCPM

Immune cell

  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • hypothalamus: 1.5 nTPM
  • basal ganglia: 1.3 nTPM
  • medulla oblongata: 1 nTPM
  • midbrain: 0.8 nTPM
  • thalamus: 0.8 nTPM
  • cerebral cortex: 0.7 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)
0.71
gnomAD pLI
0
gnomAD missense Z
0.75
DepMap mean gene effect
-0.06
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% 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

InteractionsUniProt · HPA

Protein binding partners of IGSF9 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 IGSF9 as an antibody target. Whether an autoantibody or antibody against IGSF9 could matter depends on whether native IGSF9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

IGSF9 is annotated at the cell surface, where native IGSF9 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 IGSF9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/IGSF9. 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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