Seroatlas · Human Serome Atlas

CSN2

Beta-casein

Also known as: CASB, CASB_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P05814
Gene
CSN2
Ensembl
ENSG00000135222
Chromosome
4
Canonical length
226 aa
Protein class
Predicted secreted proteins
Secretome location
Secreted in female reproductive system

OverviewNCBI Gene

This gene is a member of the beta casein family. There are two types of casein protein, beta (encoded by this gene) and kappa, both of which are secreted in human milk. Beta casein is the principal protein in human milk and the primary source of essential amino acids for a suckling infant. Beta and kappa casein proteins acting together form spherical micelles which bind within them important dietary minerals, such as calcium and phosphorous. In addition, the C-terminal 14 aa of the protein has antimicrobial activity, especially in preterm milk, displaying antibacterial activity against S. aureus and Y. enterocolitica. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2020]

Canonical amino-acid sequenceUniProt

226 residues, UniProt reviewed canonical sequence.

>P05814|CSN2
     1  MKVLILACLV ALALARETIE SLSSSEESIT EYKQKVEKVK HEDQQQGEDE HQDKIYPSFQ
    61  PQPLIYPFVE PIPYGFLPQN ILPLAQPAVV LPVPQPEIME VPKAKDTVYT KGRVMPVLKS
   121  PTIPFFDPQI PKLTDLENLH LPLPLLQPLM QQVPQPIPQT LALPPQPLWS VPQPKVLPIP
   181  QQVVPYPQRA VPVQALLLNQ ELLLNPTHQI YPVTQPLAPV HNPISV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CSN2 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
Secreted
Secreted
Yes
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.68
Highest tissue expression
538 nTPM

Expression across tissuesHPA

Tissue

  • breast: 538 nTPM
  • thymus: 5.2 nTPM
  • salivary gland: 2.9 nTPM
  • seminal vesicle: 0.4 nTPM
  • smooth muscle: 0.1 nTPM
  • testis: 0.1 nTPM

Single-cell type

  • breast lactating cells: 333,043 nCPM
  • breast hormone-responsive cells: 11 nCPM
  • breast secretory cells: 7.7 nCPM
  • salivary acinar cells: 5 nCPM
  • salivary myoepithelial cells: 4.5 nCPM
  • innate lymphoid cells: 2.4 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

  • midbrain: 0.6 nTPM
  • thalamus: 0.2 nTPM
  • amygdala: 0 nTPM
  • basal ganglia: 0 nTPM
  • cerebellum: 0 nTPM
  • cerebral cortex: 0 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)
1.37
gnomAD pLI
0
gnomAD missense Z
-1.47
DepMap mean gene effect
0.04
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 1% 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 CSN2 as an antibody target. Whether an autoantibody or antibody against CSN2 could matter depends on whether native CSN2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CSN2 is annotated as secreted, so native CSN2 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label CSN2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CSN2. 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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