Seroatlas · Human Serome Atlas

BYSL

Bystin

Also known as: BYST_HUMAN, Enp1

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

Protein identityUniProt · HPA

UniProt accession
Q13895
Gene
BYSL
Ensembl
ENSG00000112578
Chromosome
6
Canonical length
437 aa
Protein class
Predicted intracellular proteins
Subcellular location
Nucleoplasm,Nucleoli,Nucleoli rim,Mitotic chromosome

OverviewNCBI Gene

Bystin is expressed as a 2-kb major transcript and a 3.6-kb minor transcript in SNG-M cells and in human trophoblastic teratocarcinoma HT-H cells. Protein binding assays determined that bystin binds directly to trophinin and tastin, and that binding is enhanced when cytokeratins 8 and 18 are present. Immunocytochemistry of HT-H cells showed that bystin colocalizes with trophinin, tastin, and the cytokeratins, suggesting that these molecules form a complex in trophectoderm cells at the time of implantation. Using immunohistochemistry it was determined that trophinin and bystin are found in the placenta from the sixth week of pregnancy. Both proteins were localized in the cytoplasm of the syncytiotrophoblast in the chorionic villi and in endometrial decidual cells at the uteroplacental interface. After week 10, the levels of trophinin, tastin, and bystin decreased and then disappeared from placental villi. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

437 residues, UniProt reviewed canonical sequence.

>Q13895|BYSL
     1  MPKFKAARGV GGQEKHAPLA DQILAGNAVR AGVREKRRGR GTGEAEEEYV GPRLSRRILQ
    61  QARQQQEELE AEHGTGDKPA APRERTTRLG PRMPQDGSDD EDEEWPTLEK AATMTAAGHH
   121  AEVVVDPEDE RAIEMFMNKN PPARRTLADI IMEKLTEKQT EVETVMSEVS GFPMPQLDPR
   181  VLEVYRGVRE VLSKYRSGKL PKAFKIIPAL SNWEQILYVT EPEAWTAAAM YQATRIFASN
   241  LKERMAQRFY NLVLLPRVRD DVAEYKRLNF HLYMALKKAL FKPGAWFKGI LIPLCESGTC
   301  TLREAIIVGS IITKCSIPVL HSSAAMLKIA EMEYSGANSI FLRLLLDKKY ALPYRVLDAL
   361  VFHFLGFRTE KRELPVLWHQ CLLTLVQRYK ADLATDQKEA LLELLRLQPH PQLSPEIRRE
   421  LQSAVPRDVE DVPITVE

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against BYSL 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)
0.38
Highest tissue expression
28 nTPM

Expression across tissuesHPA

Tissue

  • skeletal muscle: 28 nTPM
  • urinary bladder: 14 nTPM
  • adrenal gland: 14 nTPM
  • esophagus: 13 nTPM
  • tonsil: 12 nTPM
  • adipose tissue: 12 nTPM

Single-cell type

  • oocytes: 60 nCPM
  • esophageal basal cells: 42 nCPM
  • epicardial cells: 36 nCPM
  • decidual stromal cells: 33 nCPM
  • differentiating spermatogonia: 32 nCPM
  • migrating cytotrophoblasts: 30 nCPM

Immune cell

  • plasmacytoid DC: 9.2 nTPM
  • NK-cell: 6.1 nTPM
  • myeloid DC: 6 nTPM
  • MAIT T-cell: 5.9 nTPM
  • naive B-cell: 5.6 nTPM
  • gdT-cell: 4.3 nTPM

Brain region

  • pons: 9 nTPM
  • hypothalamus: 8.5 nTPM
  • midbrain: 8.4 nTPM
  • cerebral cortex: 7.2 nTPM
  • white matter: 7.2 nTPM
  • medulla oblongata: 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)
0.81
gnomAD pLI
0
gnomAD missense Z
0.49
DepMap mean gene effect
-1.37
DepMap dependency class
pan

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 9% 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

  • Bystin
  • Bystin

KeywordsUniProt

InteractionsUniProt · HPA

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

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

Canonical record: https://seroatlas.com/gene/BYSL. 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).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...