Seroatlas · Human Serome Atlas

PIK3R2

Phosphatidylinositol 3-kinase regulatory subunit beta

Also known as: p85, P85B, P85B_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
O00459
Gene
PIK3R2
Ensembl
ENSG00000105647
Chromosome
19
Canonical length
728 aa
Protein class
Cancer-related genes, Disease related genes, Human disease related genes, Metabolic proteins, Plasma proteins, Predicted intracellular proteins, RAS pathway related proteins
Subcellular location
Golgi apparatus

OverviewNCBI Gene

Phosphatidylinositol 3-kinase (PI3K) is a lipid kinase that phosphorylates phosphatidylinositol and similar compounds, creating second messengers important in growth signaling pathways. PI3K functions as a heterodimer of a regulatory and a catalytic subunit. The protein encoded by this gene is a regulatory component of PI3K. Three transcript variants, one protein coding and the other two non-protein coding, have been found for this gene. [provided by RefSeq, Apr 2019]

Canonical amino-acid sequenceUniProt

728 residues, UniProt reviewed canonical sequence.

>O00459|PIK3R2
     1  MAGPEGFQYR ALYPFRRERP EDLELLPGDV LVVSRAALQA LGVAEGGERC PQSVGWMPGL
    61  NERTRQRGDF PGTYVEFLGP VALARPGPRP RGPRPLPARP RDGAPEPGLT LPDLPEQFSP
   121  PDVAPPLLVK LVEAIERTGL DSESHYRPEL PAPRTDWSLS DVDQWDTAAL ADGIKSFLLA
   181  LPAPLVTPEA SAEARRALRE AAGPVGPALE PPTLPLHRAL TLRFLLQHLG RVASRAPALG
   241  PAVRALGATF GPLLLRAPPP PSSPPPGGAP DGSEPSPDFP ALLVEKLLQE HLEEQEVAPP
   301  ALPPKPPKAK PASTVLANGG SPPSLQDAEW YWGDISREEV NEKLRDTPDG TFLVRDASSK
   361  IQGEYTLTLR KGGNNKLIKV FHRDGHYGFS EPLTFCSVVD LINHYRHESL AQYNAKLDTR
   421  LLYPVSKYQQ DQIVKEDSVE AVGAQLKVYH QQYQDKSREY DQLYEEYTRT SQELQMKRTA
   481  IEAFNETIKI FEEQGQTQEK CSKEYLERFR REGNEKEMQR ILLNSERLKS RIAEIHESRT
   541  KLEQQLRAQA SDNREIDKRM NSLKPDLMQL RKIRDQYLVW LTQKGARQKK INEWLGIKNE
   601  TEDQYALMED EDDLPHHEER TWYVGKINRT QAEEMLSGKR DGTFLIRESS QRGCYACSVV
   661  VDGDTKHCVI YRTATGFGFA EPYNLYGSLK ELVLHYQHAS LVQHNDALTV TLAHPVRAPG
   721  PGPPPAAR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PIK3R2 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)
0.35
Highest tissue expression
34 nTPM

Expression across tissuesHPA

Tissue

  • cerebral cortex: 34 nTPM
  • hippocampal formation: 33 nTPM
  • basal ganglia: 29 nTPM
  • skin: 25 nTPM
  • amygdala: 25 nTPM
  • esophagus: 22 nTPM

Single-cell type

  • ependymal cells: 21 nCPM
  • oligodendrocyte progenitor cells: 18 nCPM
  • brain inhibitory neurons: 14 nCPM
  • brain excitatory neurons: 14 nCPM
  • astrocytes: 13 nCPM
  • oligodendrocytes: 12 nCPM

Immune cell

  • eosinophil: 0.5 nTPM
  • naive B-cell: 0.2 nTPM
  • naive CD8 T-cell: 0.1 nTPM
  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • gdT-cell: 0 nTPM

Brain region

  • cerebral cortex: 105 nTPM
  • hippocampal formation: 105 nTPM
  • amygdala: 73 nTPM
  • basal ganglia: 66 nTPM
  • white matter: 51 nTPM
  • thalamus: 39 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about PIK3R2.

Disease | AllUniProt

Conditions PIK3R2 is implicated in, by any mechanism.

  • Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1 (MPPH1) MIM:603387

Disease | GeneticClinVar

16 pathogenic / likely-pathogenic of 584 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

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)
0.49
gnomAD pLI
0.02
gnomAD missense Z
2.33
DepMap mean gene effect
-0.13
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

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of PIK3R2 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 PIK3R2 as an antibody target. Whether an autoantibody or antibody against PIK3R2 could matter depends on whether native PIK3R2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PIK3R2 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 PIK3R2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PIK3R2. 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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