Seroatlas · Human Serome Atlas

PPP4R3A

Serine/threonine-protein phosphatase 4 regulatory subunit 3A

Also known as: FLFL1, FLJ20707, KIAA2010, MSTP033, P4R3A_HUMAN, PP4R3, SMEK1, smk-1, smk1

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

Protein identityUniProt · HPA

UniProt accession: Q6IN85
Gene: PPP4R3A
Ensembl: ENSG00000100796
Chromosome: 14
Canonical length: 833 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm,Nuclear speckles,Cytosol

OverviewNCBI Gene

Predicted to enable protein phosphatase activator activity. Predicted to be involved in DNA damage response and regulation of double-strand break repair. Predicted to act upstream of or within positive regulation of gluconeogenesis and protein dephosphorylation. Located in cytosol and nuclear speck. [provided by Alliance of Genome Resources, Apr 2025]

Canonical amino-acid sequenceUniProt

833 residues, UniProt reviewed canonical sequence.

>Q6IN85|PPP4R3A
     1  MTDTRRRVKV YTLNEDRQWD DRGTGHVSSG YVERLKGMSL LVRAESDGSL LLESKINPNT
    61  AYQKQQDTLI VWSEAENYDL ALSFQEKAGC DEIWEKICQV QGKDPSVDIT QDLVDESEEE
   121  RFDDMSSPGL ELPSCELSRL EEIAELVASS LPSPLRREKL ALALENEGYI KKLLELFHVC
   181  EDLENIEGLH HLYEIIKGIF LLNRTALFEV MFSEECIMDV IGCLEYDPAL SQPRKHREFL
   241  TKTAKFKEVI PISDPELKQK IHQTYRVQYI QDMVLPTPSV FEENMLSTLH SFIFFNKVEI
   301  VGMLQEDEKF LTDLFAQLTD EATDEEKRQE LVNFLKEFCA FSQTLQPQNR DAFFKTLSNM
   361  GILPALEVIL GMDDTQVRSA ATDIFSYLVE YNPSMVREFV MQEAQQNDDV SKKLTEQKIT
   421  SKDILLINLI IEHMICDTDP ELGGAVQLMG LLRTLVDPEN MLATANKTEK TEFLGFFYKH
   481  CMHVLTAPLL ANTTEDKPSK DDFQTAQLLA LVLELLTFCV EHHTYHIKNY IINKDILRRV
   541  LVLMASKHAF LALCALRFKR KIIGLKDEFY NRYIMKSFLF EPVVKAFLNN GSRYNLMNSA
   601  IIEMFEFIRV EDIKSLTAHV IENYWKALED VDYVQTFKGL KLRFEQQRER QDNPKLDSMR
   661  SILRNHRYRR DARTLEDEEE MWFNTDEDDM EDGEAVVSPS DKTKNDDDIM DPISKFMERK
   721  KLKESEEKEV LLKTNLSGRQ SPSFKLSLSS GTKTNLTSQS STTNLPGSPG SPGSPGSPGS
   781  PGSVPKNTSQ TAAITTKGGL VGLVDYPDDD EDDDEDEDKE DTLPLSKKAK FDS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PPP4R3A 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): 0.36
Highest tissue expression: 47 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 47 nTPM
lymph node: 27 nTPM
thymus: 26 nTPM
tonsil: 24 nTPM
spleen: 22 nTPM
liver: 21 nTPM

Single-cell type

monocytes: 270 nCPM
b-cells: 231 nCPM
neutrophil progenitors: 202 nCPM
innate lymphoid cells: 192 nCPM
epididymal efferent duct ciliated cells: 190 nCPM
t-cells: 170 nCPM

Immune cell

NK-cell: 9.1 nTPM
naive B-cell: 7.5 nTPM
T-reg: 6.9 nTPM
MAIT T-cell: 6.7 nTPM
basophil: 6.3 nTPM
naive CD4 T-cell: 5.6 nTPM

Brain region

white matter: 28 nTPM
cerebellum: 27 nTPM
choroid plexus: 26 nTPM
thalamus: 23 nTPM
amygdala: 23 nTPM
basal ganglia: 22 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): 0.19
gnomAD pLI: 1
DepMap mean gene effect: -0.25
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

protein phosphatase activator activity

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of PPP4R3A 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 PPP4R3A as an antibody target. Whether an autoantibody or antibody against PPP4R3A could matter depends on whether native PPP4R3A is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PPP4R3A 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 PPP4R3A as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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