Seroatlas · Human Serome Atlas

PAK4

Serine/threonine-protein kinase PAK 4

Also known as: PAK4_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
O96013
Gene
PAK4
Ensembl
ENSG00000130669
Chromosome
19
Canonical length
591 aa
Protein class
Enzymes, Predicted intracellular proteins, RAS pathway related proteins
Subcellular location
Plasma membrane,Cell Junctions

OverviewNCBI Gene

PAK proteins, a family of serine/threonine p21-activating kinases, include PAK1, PAK2, PAK3 and PAK4. PAK proteins are critical effectors that link Rho GTPases to cytoskeleton reorganization and nuclear signaling. They serve as targets for the small GTP binding proteins Cdc42 and Rac and have been implicated in a wide range of biological activities. PAK4 interacts specifically with the GTP-bound form of Cdc42Hs and weakly activates the JNK family of MAP kinases. PAK4 is a mediator of filopodia formation and may play a role in the reorganization of the actin cytoskeleton. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

591 residues, UniProt reviewed canonical sequence.

>O96013|PAK4
     1  MFGKRKKRVE ISAPSNFEHR VHTGFDQHEQ KFTGLPRQWQ SLIEESARRP KPLVDPACIT
    61  SIQPGAPKTI VRGSKGAKDG ALTLLLDEFE NMSVTRSNSL RRDSPPPPAR ARQENGMPEE
   121  PATTARGGPG KAGSRGRFAG HSEAGGGSGD RRRAGPEKRP KSSREGSGGP QESSRDKRPL
   181  SGPDVGTPQP AGLASGAKLA AGRPFNTYPR ADTDHPSRGA QGEPHDVAPN GPSAGGLAIP
   241  QSSSSSSRPP TRARGAPSPG VLGPHASEPQ LAPPACTPAA PAVPGPPGPR SPQREPQRVS
   301  HEQFRAALQL VVDPGDPRSY LDNFIKIGEG STGIVCIATV RSSGKLVAVK KMDLRKQQRR
   361  ELLFNEVVIM RDYQHENVVE MYNSYLVGDE LWVVMEFLEG GALTDIVTHT RMNEEQIAAV
   421  CLAVLQALSV LHAQGVIHRD IKSDSILLTH DGRVKLSDFG FCAQVSKEVP RRKSLVGTPY
   481  WMAPELISRL PYGPEVDIWS LGIMVIEMVD GEPPYFNEPP LKAMKMIRDN LPPRLKNLHK
   541  VSPSLKGFLD RLLVRDPAQR ATAAELLKHP FLAKAGPPAS IVPLMRQNRT R

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PAK4 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)
0.47
Highest tissue expression
42 nTPM

Expression across tissuesHPA

Tissue

  • esophagus: 42 nTPM
  • salivary gland: 40 nTPM
  • prostate: 39 nTPM
  • skin: 39 nTPM
  • lung: 37 nTPM
  • kidney: 37 nTPM

Single-cell type

  • esophageal apical cells: 106 nCPM
  • extravillous trophoblasts: 96 nCPM
  • syncytiotrophoblasts: 92 nCPM
  • distal convoluted tubule cells: 82 nCPM
  • renal connecting tubule cells: 80 nCPM
  • renal collecting duct intercalated cells: 78 nCPM

Immune cell

  • eosinophil: 1.2 nTPM
  • memory CD8 T-cell: 1.1 nTPM
  • myeloid DC: 0.9 nTPM
  • NK-cell: 0.9 nTPM
  • T-reg: 0.9 nTPM
  • MAIT T-cell: 0.8 nTPM

Brain region

  • basal ganglia: 39 nTPM
  • medulla oblongata: 38 nTPM
  • midbrain: 37 nTPM
  • cerebral cortex: 37 nTPM
  • amygdala: 36 nTPM
  • white matter: 36 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)
0.78
gnomAD pLI
0
gnomAD missense Z
0.59
DepMap mean gene effect
-0.05
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 10% 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 PAK4 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 PAK4 as an antibody target. Whether an autoantibody or antibody against PAK4 could matter depends on whether native PAK4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PAK4 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 PAK4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/PAK4. 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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