Seroatlas · Human Serome Atlas

PPP4R1

Serine/threonine-protein phosphatase 4 regulatory subunit 1

Also known as: PP4R1, PP4R1_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q8TF05
Gene
PPP4R1
Ensembl
ENSG00000154845
Chromosome
18
Canonical length
950 aa
Protein class
Predicted intracellular proteins
Subcellular location
Plasma membrane,Actin filaments,Cytosol,Perinuclear theca,Calyx,Mid piece,Principal piece,End piece

OverviewNCBI Gene

This gene encodes one of several alternate regulatory subunits of serine/threonine protein phosphatase 4 (PP4). The protein features multiple HEAT repeats. This protein forms a complex with PP4RC. This complex may have a distinct role from other PP4 complexes, including regulation of HDAC3 (Zhang et al., PMID: 15805470). There is also a transcribed pseudogene on chromosome 20. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jun 2012]

Canonical amino-acid sequenceUniProt

950 residues, UniProt reviewed canonical sequence.

>Q8TF05|PPP4R1
     1  MADLSLLQED LQEDADGFGV DDYSSESDVI IIPSALDFVS QDEMLTPLGR LDKYAASENI
    61  FNRQMVARSL LDTLREVCDD ERDCIAVLER ISRLADDSEP TVRAELMEQV PHIALFCQEN
   121  RPSIPYAFSK FLLPIVVRYL ADQNNQVRKT SQAALLALLE QELIERFDVE TKVCPVLIEL
   181  TAPDSNDDVK TEAVAIMCKM APMVGKDITE RLILPRFCEM CCDCRMFHVR KVCAANFGDI
   241  CSVVGQQATE EMLLPRFFQL CSDNVWGVRK ACAECFMAVS CATCQEIRRT KLSALFINLI
   301  SDPSRWVRQA AFQSLGPFIS TFANPSSSGQ YFKEESKSSE EMSVENKNRT RDQEAPEDVQ
   361  VRPEDTPSDL SVSNSSVILE NTMEDHAAEA SGKPLGEISV PLDSSLLCTL SSESHQEAAS
   421  NENDKKPGNY KSMLRPEVGT TSQDSALLDQ ELYNSFHFWR TPLPEIDLDI ELEQNSGGKP
   481  SPEGPEEESE GPVPSSPNIT MATRKELEEM IENLEPHIDD PDVKAQVEVL SAALRASSLD
   541  AHEETISIEK RSDLQDELDI NELPNCKINQ EDSVPLISDA VENMDSTLHY IHSDSDLSNN
   601  SSFSPDEERR TKVQDVVPQA LLDQYLSMTD PSRAQTVDTE IAKHCAYSLP GVALTLGRQN
   661  WHCLRETYET LASDMQWKVR RTLAFSIHEL AVILGDQLTA ADLVPIFNGF LKDLDEVRIG
   721  VLKHLHDFLK LLHIDKRREY LYQLQEFLVT DNSRNWRFRA ELAEQLILLL ELYSPRDVYD
   781  YLRPIALNLC ADKVSSVRWI SYKLVSEMVK KLHAATPPTF GVDLINELVE NFGRCPKWSG
   841  RQAFVFVCQT VIEDDCLPMD QFAVHLMPHL LTLANDRVPN VRVLLAKTLR QTLLEKDYFL
   901  ASASCHQEAV EQTIMALQMD RDSDVKYFAS IHPASTKISE DAMSTASSTY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PPP4R1 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
68 nTPM

Expression across tissuesHPA

Tissue

  • esophagus: 68 nTPM
  • urinary bladder: 38 nTPM
  • vagina: 34 nTPM
  • testis: 33 nTPM
  • lung: 33 nTPM
  • cervix: 31 nTPM

Single-cell type

  • esophageal apical cells: 725 nCPM
  • neutrophils: 524 nCPM
  • alveolar cells type 1: 395 nCPM
  • urothelial cells: 351 nCPM
  • ocular epithelial cells: 342 nCPM
  • transitional alveolar cells: 281 nCPM

Immune cell

  • neutrophil: 36 nTPM
  • basophil: 15 nTPM
  • eosinophil: 11 nTPM
  • myeloid DC: 7 nTPM
  • classical monocyte: 6.1 nTPM
  • MAIT T-cell: 5 nTPM

Brain region

  • white matter: 32 nTPM
  • choroid plexus: 28 nTPM
  • basal ganglia: 28 nTPM
  • cerebellum: 27 nTPM
  • cerebral cortex: 26 nTPM
  • pons: 26 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)
0.24
gnomAD pLI
1
gnomAD missense Z
2.04
DepMap mean gene effect
0.01
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 7% 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 PPP4R1 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 PPP4R1 as an antibody target. Whether an autoantibody or antibody against PPP4R1 could matter depends on whether native PPP4R1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PPP4R1 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 PPP4R1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PPP4R1. 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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