Seroatlas · Human Serome Atlas

PABPC4

Polyadenylate-binding protein 4

Also known as: APP-1, iPABP, PABP4_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q13310
Gene
PABPC4
Ensembl
ENSG00000090621
Chromosome
1
Canonical length
644 aa
Protein class
Predicted intracellular proteins
Subcellular location
Cytosol

OverviewNCBI Gene

Poly(A)-binding proteins (PABPs) bind to the poly(A) tail present at the 3-prime ends of most eukaryotic mRNAs. PABPC4 or IPABP (inducible PABP) was isolated as an activation-induced T-cell mRNA encoding a protein. Activation of T cells increased PABPC4 mRNA levels in T cells approximately 5-fold. PABPC4 contains 4 RNA-binding domains and proline-rich C terminus. PABPC4 is localized primarily to the cytoplasm. It is suggested that PABPC4 might be necessary for regulation of stability of labile mRNA species in activated T cells. PABPC4 was also identified as an antigen, APP1 (activated-platelet protein-1), expressed on thrombin-activated rabbit platelets. PABPC4 may also be involved in the regulation of protein translation in platelets and megakaryocytes or may participate in the binding or stabilization of polyadenylates in platelet dense granules. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. This protein has also been found to interact with coronavirus nucleocapsid proteins and is thought to inhibit coronavirus replication. [provided by RefSeq, Nov 2021]

Canonical amino-acid sequenceUniProt

644 residues, UniProt reviewed canonical sequence.

>Q13310|PABPC4
     1  MNAAASSYPM ASLYVGDLHS DVTEAMLYEK FSPAGPVLSI RVCRDMITRR SLGYAYVNFQ
    61  QPADAERALD TMNFDVIKGK PIRIMWSQRD PSLRKSGVGN VFIKNLDKSI DNKALYDTFS
   121  AFGNILSCKV VCDENGSKGY AFVHFETQEA ADKAIEKMNG MLLNDRKVFV GRFKSRKERE
   181  AELGAKAKEF TNVYIKNFGE EVDDESLKEL FSQFGKTLSV KVMRDPNGKS KGFGFVSYEK
   241  HEDANKAVEE MNGKEISGKI IFVGRAQKKV ERQAELKRKF EQLKQERISR YQGVNLYIKN
   301  LDDTIDDEKL RKEFSPFGSI TSAKVMLEDG RSKGFGFVCF SSPEEATKAV TEMNGRIVGS
   361  KPLYVALAQR KEERKAHLTN QYMQRVAGMR ALPANAILNQ FQPAAGGYFV PAVPQAQGRP
   421  PYYTPNQLAQ MRPNPRWQQG GRPQGFQGMP SAIRQSGPRP TLRHLAPTGS ECPDRLAMDF
   481  GGAGAAQQGL TDSCQSGGVP TAVQNLAPRA AVAAAAPRAV APYKYASSVR SPHPAIQPLQ
   541  APQPAVHVQG QEPLTASMLA AAPPQEQKQM LGERLFPLIQ TMHSNLAGKI TGMLLEIDNS
   601  ELLHMLESPE SLRSKVDEAV AVLQAHHAKK EAAQKVGAVA AATS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PABPC4 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)
0.44
Highest tissue expression
448 nTPM

Expression across tissuesHPA

Tissue

  • skeletal muscle: 448 nTPM
  • pancreas: 339 nTPM
  • tongue: 229 nTPM
  • stomach: 113 nTPM
  • heart muscle: 96 nTPM
  • ovary: 82 nTPM

Single-cell type

  • kupffer cells: 566 nCPM
  • pancreatic acinar cells: 444 nCPM
  • plasma cells: 320 nCPM
  • undifferentiated spermatogonia: 287 nCPM
  • parietal cells: 286 nCPM
  • gastric chief cells: 244 nCPM

Immune cell

  • non-classical monocyte: 33 nTPM
  • naive CD4 T-cell: 25 nTPM
  • intermediate monocyte: 23 nTPM
  • memory CD4 T-cell: 21 nTPM
  • naive B-cell: 20 nTPM
  • myeloid DC: 19 nTPM

Brain region

  • white matter: 80 nTPM
  • medulla oblongata: 75 nTPM
  • thalamus: 74 nTPM
  • choroid plexus: 70 nTPM
  • spinal cord: 69 nTPM
  • pons: 69 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)
0.23
gnomAD pLI
1
gnomAD missense Z
2.92
DepMap mean gene effect
-0.12
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

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of PABPC4 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 PABPC4 as an antibody target. Whether an autoantibody or antibody against PABPC4 could matter depends on whether native PABPC4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PABPC4 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 PABPC4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PABPC4. 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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