Seroatlas · Human Serome Atlas

PPP1CA

Serine/threonine-protein phosphatase PP1-alpha catalytic subunit

Also known as: PP-1A, PP1A, PP1A_HUMAN, PP1alpha, PPP1A

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

Protein identityUniProt · HPA

UniProt accession
P62136
Gene
PPP1CA
Ensembl
ENSG00000172531
Chromosome
11
Canonical length
330 aa
Protein class
Enzymes, Metabolic proteins, Plasma proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Plasma membrane,Cytosol,Flagellar centriole,Mid piece,End piece

OverviewNCBI Gene

The protein encoded by this gene is one of the three catalytic subunits of protein phosphatase 1 (PP1). This broadly expressed gene encodes the alpha subunit of the PP1 complex that associates with over 200 regulatory proteins to form holoenzymes which dephosphorylate their biological targets with high specificity. PP1 is a serine/threonine specific protein phosphatase known to be involved in the regulation of a variety of cellular processes, such as cell division, glycogen metabolism, muscle contractility, protein synthesis, and HIV-1 viral transcription. Increased PP1 activity has been observed in the end stage of heart failure. Studies suggest that PP1 is an important regulator of cardiac function and that PP1 deregulation is implicated in diabetes and multiple types of cancer. Three alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2020]

Canonical amino-acid sequenceUniProt

330 residues, UniProt reviewed canonical sequence.

>P62136|PPP1CA
     1  MSDSEKLNLD SIIGRLLEVQ GSRPGKNVQL TENEIRGLCL KSREIFLSQP ILLELEAPLK
    61  ICGDIHGQYY DLLRLFEYGG FPPESNYLFL GDYVDRGKQS LETICLLLAY KIKYPENFFL
   121  LRGNHECASI NRIYGFYDEC KRRYNIKLWK TFTDCFNCLP IAAIVDEKIF CCHGGLSPDL
   181  QSMEQIRRIM RPTDVPDQGL LCDLLWSDPD KDVQGWGEND RGVSFTFGAE VVAKFLHKHD
   241  LDLICRAHQV VEDGYEFFAK RQLVTLFSAP NYCGEFDNAG AMMSVDETLM CSFQILKPAD
   301  KNKGKYGQFS GLNPGGRPIT PPRNSAKAKK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PPP1CA 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)
0.24
Highest tissue expression
181 nTPM

Expression across tissuesHPA

Tissue

  • esophagus: 181 nTPM
  • tonsil: 146 nTPM
  • spleen: 141 nTPM
  • lymph node: 138 nTPM
  • liver: 125 nTPM
  • skeletal muscle: 124 nTPM

Single-cell type

  • esophageal apical cells: 821 nCPM
  • extravillous trophoblasts: 647 nCPM
  • syncytiotrophoblasts: 475 nCPM
  • esophageal suprabasal cells: 458 nCPM
  • cytotrophoblasts: 416 nCPM
  • esophageal basal cells: 412 nCPM

Immune cell

  • total PBMC: 2,042 nTPM
  • eosinophil: 1,237 nTPM
  • non-classical monocyte: 1,191 nTPM
  • T-reg: 1,102 nTPM
  • intermediate monocyte: 964 nTPM
  • basophil: 925 nTPM

Brain region

  • basal ganglia: 64 nTPM
  • medulla oblongata: 60 nTPM
  • white matter: 60 nTPM
  • thalamus: 57 nTPM
  • spinal cord: 51 nTPM
  • pons: 51 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)
0.27
gnomAD pLI
0.99
gnomAD missense Z
3.26
DepMap mean gene effect
-0.64
DepMap dependency class
common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% 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 PPP1CA 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 PPP1CA as an antibody target. Whether an autoantibody or antibody against PPP1CA could matter depends on whether native PPP1CA is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PPP1CA 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 PPP1CA as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PPP1CA. 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...