Seroatlas · Human Serome Atlas

KPTN

KICSTOR complex protein kaptin

Also known as: 2E4, KICS4, KPTN_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9Y664
Gene
KPTN
Ensembl
ENSG00000118162
Chromosome
19
Canonical length
436 aa
Protein class
Disease related genes, Human disease related genes, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Vesicles,Plasma membrane

OverviewNCBI Gene

This gene encodes a filamentous-actin-associated protein, which is involved in actin dynamics and plays an important role in neuromorphogenesis. This protein is part of the KICSTOR protein complex that localizes to lysosomes. Mutations in this gene result in an autosomal recessive form of intellectual disability. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Jul 2017]

Canonical amino-acid sequenceUniProt

436 residues, UniProt reviewed canonical sequence.

>Q9Y664|KPTN
     1  MMGEAAVAAG PCPLREDSFT RFSSQSNVYG LAGGAGGRGE LLAATLKGKV LGFRYQDLRQ
    61  KIRPVAKELQ FNYIPVDAEI VSIDTFNKSP PKRGLVVGIT FIKDSGDKGS PFLNIYCDYE
   121  PGSEYNLDSI AQSCLNLELQ FTPFQLCHAE VQVGDQLETV FLLSGNDPAI HLYKENEGLH
   181  QFEEQPVENL FPELTNLTSS VLWLDVHNFP GTSRRLSALG CQSGYVRVAH VDQRSREVLQ
   241  MWSVLQDGPI SRVIVFSLSA AKETKDRPLQ DEYSVLVASM LEPAVVYRDL LNRGLEDQLL
   301  LPGSDQFDSV LCSLVTDVDL DGRPEVLVAT YGQELLCYKY RGPESGLPEA QHGFHLLWQR
   361  SFSSPLLAMA HVDLTGDGLQ ELAVVSLKGV HILQHSLIQA SELVLTRLRH QVEQRRRRLQ
   421  GLEDGAGAGP AENAAS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against KPTN 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
Other membrane
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.28
Highest tissue expression
19 nTPM

Expression across tissuesHPA

Tissue

  • cerebellum: 19 nTPM
  • pituitary gland: 10 nTPM
  • basal ganglia: 9.8 nTPM
  • salivary gland: 9.5 nTPM
  • hippocampal formation: 8.9 nTPM
  • cerebral cortex: 8.7 nTPM

Single-cell type

  • differentiating spermatogonia: 23 nCPM
  • pdcs: 20 nCPM
  • cytotrophoblasts: 19 nCPM
  • syncytiotrophoblasts: 17 nCPM
  • esophageal basal cells: 17 nCPM
  • undifferentiated spermatogonia: 16 nCPM

Immune cell

  • plasmacytoid DC: 24 nTPM
  • non-classical monocyte: 5.4 nTPM
  • myeloid DC: 4.6 nTPM
  • classical monocyte: 3.9 nTPM
  • intermediate monocyte: 3.4 nTPM
  • neutrophil: 3.2 nTPM

Brain region

  • cerebellum: 7.4 nTPM
  • medulla oblongata: 6.9 nTPM
  • hippocampal formation: 6.8 nTPM
  • basal ganglia: 6.6 nTPM
  • white matter: 6.5 nTPM
  • midbrain: 6 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about KPTN.

Disease | AllUniProt

Conditions KPTN is implicated in, by any mechanism.

  • Intellectual developmental disorder, autosomal recessive 41 (MRT41) MIM:615637

Disease | GeneticClinVar

23 pathogenic / likely-pathogenic of 232 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

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)
0.81
gnomAD pLI
0
gnomAD missense Z
1.45
DepMap mean gene effect
-0.03
DepMap dependency class
none

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

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

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