Seroatlas · Human Serome Atlas

ISY1

Pre-mRNA-splicing factor ISY1 homolog

Also known as: fSAP33, ISY1_HUMAN, KIAA1160

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

Protein identityUniProt · HPA

UniProt accession: Q9ULR0
Gene: ISY1
Ensembl: ENSG00000240682
Chromosome: 3
Canonical length: 285 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nuclear speckles

OverviewNCBI Gene

Enables RNA binding activity. Involved in mRNA splicing, via spliceosome. Located in nucleus. Part of U2-type catalytic step 1 spliceosome and catalytic step 2 spliceosome. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

285 residues, UniProt reviewed canonical sequence.

>Q9ULR0|ISY1
     1  MARNAEKAMT ALARFRQAQL EEGKVKERRP FLASECTELP KAEKWRRQII GEISKKVAQI
    61  QNAGLGEFRI RDLNDEINKL LREKGHWEVR IKELGGPDYG KVGPKMLDHE GKEVPGNRGY
   121  KYFGAAKDLP GVRELFEKEP LPPPRKTRAE LMKAIDFEYY GYLDEDDGVI VPLEQEYEKK
   181  LRAELVEKWK AEREARLARG EKEEEEEEEE EINIYAVTEE ESDEEGSQEK GGDDSQQKFI
   241  AHVPVPSQQE IEEALVRRKK MELLQKYASE TLQAQSEEAR RLLGY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ISY1 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): 0.48
Highest tissue expression: 48 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 48 nTPM
skeletal muscle: 33 nTPM
lymph node: 30 nTPM
tonsil: 28 nTPM
thymus: 21 nTPM
placenta: 21 nTPM

Single-cell type

choroid plexus epithelial cells: 17 nCPM
brain excitatory neurons: 15 nCPM
brain inhibitory neurons: 14 nCPM
oligodendrocytes: 14 nCPM
microglia: 14 nCPM
other brain neurons: 13 nCPM

Immune cell

eosinophil: 94 nTPM
neutrophil: 91 nTPM
NK-cell: 85 nTPM
basophil: 79 nTPM
T-reg: 74 nTPM
myeloid DC: 63 nTPM

Brain region

cerebellum: 14 nTPM
medulla oblongata: 13 nTPM
midbrain: 13 nTPM
cerebral cortex: 13 nTPM
amygdala: 13 nTPM
hypothalamus: 13 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): 0.11
gnomAD pLI: 1
gnomAD missense Z: 1.24
DepMap mean gene effect: -1.04
DepMap dependency class: common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 12% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

RNA binding

Cellular components

Protein domainsUniProt · Pfam · InterPro

Helix hairpin bin domain superfamily
Pre-mRNA-splicing factor Isy1
Pre-mRNA-splicing factor Isy1 superfamily
Isy1-like splicing family

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of ISY1 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 ISY1 as an antibody target. Whether an autoantibody or antibody against ISY1 could matter depends on whether native ISY1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

ISY1 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 ISY1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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