Seroatlas · Human Serome Atlas

PIK3R5

Phosphoinositide 3-kinase regulatory subunit 5

Also known as: p101, P101-PI3K, PI3R5_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q8WYR1
Gene
PIK3R5
Ensembl
ENSG00000141506
Chromosome
17
Canonical length
880 aa
Protein class
Disease related genes, Human disease related genes, Metabolic proteins, Predicted intracellular proteins
Subcellular location
Centriolar satellite,Cytosol

OverviewNCBI Gene

Phosphatidylinositol 3-kinases (PI3Ks) phosphorylate the inositol ring of phosphatidylinositol at the 3-prime position, and play important roles in cell growth, proliferation, differentiation, motility, survival and intracellular trafficking. The PI3Ks are divided into three classes: I, II and III, and only the class I PI3Ks are involved in oncogenesis. This gene encodes the 101 kD regulatory subunit of the class I PI3K gamma complex, which is a dimeric enzyme, consisting of a 110 kD catalytic subunit gamma and a regulatory subunit of either 55, 87 or 101 kD. This protein recruits the catalytic subunit from the cytosol to the plasma membrane through high-affinity interaction with G-beta-gamma proteins. Multiple alternatively spliced transcript variants encoding two distinct isoforms have been found. [provided by RefSeq, Oct 2011]

Canonical amino-acid sequenceUniProt

880 residues, UniProt reviewed canonical sequence.

>Q8WYR1|PIK3R5
     1  MQPGATTCTE DRIQHALERC LHGLSLSRRS TSWSAGLCLN CWSLQELVSR DPGHFLILLE
    61  QILQKTREVQ EKGTYDLLTP LALLFYSTVL CTPHFPPDSD LLLKAASTYH RFLTWPVPYC
   121  SICQELLTFI DAELKAPGIS YQRLVRAEQG LPIRSHRSST VTVLLLNPVE VQAEFLAVAN
   181  KLSTPGHSPH SAYTTLLLHA FQATFGAHCD VPGLHCRLQA KTLAELEDIF TETAEAQELA
   241  SGIGDAAEAR RWLRTKLQAV GEKAGFPGVL DTAKPGKLHT IPIPVARCYT YSWSQDSFDI
   301  LQEILLKEQE LLQPGILGDD EEEEEEEEEV EEDLETDGHC AERDSLLSTS SLASHDSTLS
   361  LASSQASGPA LSRHLLTSFV SGLSDGMDSG YVEDSEESSS EWPWRRGSQE RRGHRRPGQK
   421  FIRIYKLFKS TSQLVLRRDS RSLEGSSDTA LPLRRAGSLC SPLDEPVSPP SRAQRSRSLP
   481  QPKLGTQLPS WLLAPASRPQ RRRPFLSGDE DPKASTLRVV VFGSDRISGK VARAYSNLRR
   541  LENNRPLLTR FFKLQFFYVP VKRSHGTSPG ACPPPRSQTP SPPTDSPRHA SPGELGTTPW
   601  EESTNDISHY LGMLDPWYER NVLGLMHLPP EVLCQQSLKA EAQALEGSPT QLPILADMLL
   661  YYCRFAARPV LLQVYQTELT FITGEKTTEI FIHSLELGHS AATRAIKASG PGSKRLGIDG
   721  DREAVPLTLQ IIYSKGAISG RSRWSNLEKV CTSVNLNKAC RKQEELDSSM EALTLNLTEV
   781  VKRQNSKSKK GFNQISTSQI KVDKVQIIGS NSCPFAVCLD QDERKILQSV VRCEVSPCYK
   841  PEKSDLSSPP QTPPDLPAQA APDLCSLLCL PIMTFSGALP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PIK3R5 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
Cell surface
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.38
Highest tissue expression
84 nTPM

Expression across tissuesHPA

Tissue

  • bone marrow: 84 nTPM
  • spleen: 21 nTPM
  • appendix: 19 nTPM
  • lung: 14 nTPM
  • lymph node: 13 nTPM
  • thymus: 12 nTPM

Single-cell type

  • neutrophils: 2,075 nCPM
  • monocytes: 812 nCPM
  • macrophages: 460 nCPM
  • nk-cells: 383 nCPM
  • cdc: 375 nCPM
  • pdcs: 358 nCPM

Immune cell

  • neutrophil: 35 nTPM
  • non-classical monocyte: 20 nTPM
  • gdT-cell: 19 nTPM
  • total PBMC: 17 nTPM
  • classical monocyte: 16 nTPM
  • memory CD8 T-cell: 16 nTPM

Brain region

  • thalamus: 18 nTPM
  • cerebral cortex: 18 nTPM
  • white matter: 13 nTPM
  • medulla oblongata: 10 nTPM
  • pons: 9.8 nTPM
  • spinal cord: 8 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about PIK3R5.

Disease | AllUniProt

Conditions PIK3R5 is implicated in, by any mechanism.

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)
0.39
gnomAD pLI
0.3
gnomAD missense Z
2.86
DepMap mean gene effect
-0.02
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% 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 PIK3R5 as an antibody target. Whether an autoantibody or antibody against PIK3R5 could matter depends on whether native PIK3R5 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PIK3R5 is annotated at the cell surface, where native PIK3R5 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label PIK3R5 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PIK3R5. 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...