Seroatlas · Human Serome Atlas

ISYNA1

Inositol-3-phosphate synthase 1

Also known as: Ino1, INO1_HUMAN, INOS, IPS

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

Protein identityUniProt · HPA

UniProt accession
Q9NPH2
Gene
ISYNA1
Ensembl
ENSG00000105655
Chromosome
19
Canonical length
558 aa
Protein class
Enzymes, Metabolic proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Cytosol

OverviewNCBI Gene

This gene encodes an inositol-3-phosphate synthase enzyme. The encoded protein plays a critical role in the myo-inositol biosynthesis pathway by catalyzing the rate-limiting conversion of glucose 6-phosphate to myoinositol 1-phosphate. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene, and a pseudogene of this gene is located on the short arm of chromosome 4. [provided by RefSeq, Nov 2011]

Canonical amino-acid sequenceUniProt

558 residues, UniProt reviewed canonical sequence.

>Q9NPH2|ISYNA1
     1  MEAAAQFFVE SPDVVYGPEA IEAQYEYRTT RVSREGGVLK VHPTSTRFTF RTARQVPRLG
    61  VMLVGWGGNN GSTLTAAVLA NRLRLSWPTR SGRKEANYYG SLTQAGTVSL GLDAEGQEVF
   121  VPFSAVLPMV APNDLVFDGW DISSLNLAEA MRRAKVLDWG LQEQLWPHME ALRPRPSVYI
   181  PEFIAANQSA RADNLIPGSR AQQLEQIRRD IRDFRSSAGL DKVIVLWTAN TERFCEVIPG
   241  LNDTAENLLR TIELGLEVSP STLFAVASIL EGCAFLNGSP QNTLVPGALE LAWQHRVFVG
   301  GDDFKSGQTK VKSVLVDFLI GSGLKTMSIV SYNHLGNNDG ENLSAPLQFR SKEVSKSNVV
   361  DDMVQSNPVL YTPGEEPDHC VVIKYVPYVG DSKRALDEYT SELMLGGTNT LVLHNTCEDS
   421  LLAAPIMLDL ALLTELCQRV SFCTDMDPEP QTFHPVLSLL SFLFKAPLVP PGSPVVNALF
   481  RQRSCIENIL RACVGLPPQN HMLLEHKMER PGPSLKRVGP VAATYPMLNK KGPVPAATNG
   541  CTGDANGHLQ EEPPMPTT

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ISYNA1 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
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.28
Highest tissue expression
220 nTPM

Expression across tissuesHPA

Tissue

  • testis: 220 nTPM
  • choroid plexus: 200 nTPM
  • kidney: 126 nTPM
  • ovary: 94 nTPM
  • blood vessel: 81 nTPM
  • fallopian tube: 77 nTPM

Single-cell type

  • cytotrophoblasts: 1,352 nCPM
  • syncytiotrophoblasts: 1,149 nCPM
  • migrating cytotrophoblasts: 793 nCPM
  • granulosa cells: 649 nCPM
  • late spermatids: 382 nCPM
  • fallopian secretory cells: 345 nCPM

Immune cell

  • NK-cell: 15 nTPM
  • naive CD8 T-cell: 9 nTPM
  • memory CD4 T-cell: 8.2 nTPM
  • gdT-cell: 8.1 nTPM
  • memory CD8 T-cell: 6.9 nTPM
  • MAIT T-cell: 6.2 nTPM

Brain region

  • choroid plexus: 466 nTPM
  • hypothalamus: 42 nTPM
  • hippocampal formation: 30 nTPM
  • thalamus: 30 nTPM
  • midbrain: 29 nTPM
  • medulla oblongata: 26 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)
0.84
gnomAD pLI
0
gnomAD missense Z
1.27
DepMap mean gene effect
-0.26
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

  • inositol-3-phosphate synthase activity

Cellular components

Protein domainsUniProt · Pfam · InterPro

  • NAD(P)-binding domain superfamily
  • Myo-inositol-1-phosphate synthase
  • Myo-inositol-1-phosphate synthase, GAPDH-like
  • Myo-inositol-1-phosphate synthase
  • Myo-inositol-1-phosphate synthase

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads ISYNA1 as an antibody target. Whether an autoantibody or antibody against ISYNA1 could matter depends on whether native ISYNA1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

ISYNA1 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 ISYNA1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/ISYNA1. 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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