Seroatlas · Human Serome Atlas

KCTD18

BTB/POZ domain-containing protein KCTD18

Also known as: 6530404F10Rik, FLJ31322, FLJ37818, KCD18_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q6PI47
Gene: KCTD18
Ensembl: ENSG00000155729
Chromosome: 2
Canonical length: 426 aa
Protein class: Predicted intracellular proteins
Subcellular location: Mitochondria

OverviewNCBI Gene

Predicted to enable identical protein binding activity. Predicted to be involved in monoatomic ion transmembrane transport and protein homooligomerization. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

426 residues, UniProt reviewed canonical sequence.

>Q6PI47|KCTD18
     1  MEGHKAEEEV LDVLRLNVGG CIYTARRESL CRFKDSMLAS MFSGRFPLKT DESGACVIDR
    61  DGRLFKYLLD YLHGEVQIPT DEQTRIALQE EADYFGIPYP YSLSDHLANE METYSLRSNI
   121  ELKKALTDFC DSYGLVCNKP TVWVLHYLNT SGASCESRII GVYATKTDGT DAIEKQLGGR
   181  IHSKGIFKRE AGNNVQYIWS YYSVAELKKM MDAFDAWEGK GVSYWRVPHE LIECWTLEER
   241  PLLGSLRHMA PIRKRRLITF NEADESVNYK TGPKPVRFLG PSTSTQIKVK NSASVTVSPA
   301  SAIQTSAGAT ANRFQSGSRR KAAQRSAPSR ATALVGTGAP GHPQASPGAA SAENGGTHLP
   361  PAKVLLSDKK PTPQRVIKLK RTPLCATAPC LPSPTATRQA NSLKPLPGEA ARALGVRTEN
   421  GKNKGN

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against KCTD18 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: Unknown
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.51
Highest tissue expression: 13 nTPM

Expression across tissuesHPA

Tissue

thyroid gland: 13 nTPM
blood vessel: 12 nTPM
spinal cord: 12 nTPM
pancreas: 11 nTPM
prostate: 10 nTPM
lymph node: 10 nTPM

Single-cell type

early primary spermatocytes: 30 nCPM
platelets: 28 nCPM
gonadotrophs: 25 nCPM
megakaryocytes: 25 nCPM
early spermatids: 24 nCPM
respiratory ciliated cells: 24 nCPM

Immune cell

basophil: 7.9 nTPM
eosinophil: 6.4 nTPM
naive CD4 T-cell: 5.2 nTPM
naive CD8 T-cell: 5.1 nTPM
T-reg: 5 nTPM
MAIT T-cell: 4.9 nTPM

Brain region

basal ganglia: 9.9 nTPM
medulla oblongata: 9.4 nTPM
white matter: 9.3 nTPM
choroid plexus: 9 nTPM
midbrain: 9 nTPM
spinal cord: 9 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): 1.42
gnomAD pLI: 0
gnomAD missense Z: 0.37
DepMap mean gene effect: -0.02
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

protein homooligomerization

Molecular functions

identical protein binding

Protein domainsUniProt · Pfam · InterPro

Potassium channel tetramerisation-type BTB domain
SKP1/BTB/POZ domain superfamily
BTB/POZ domain
BTB/POZ domain-containing protein KCTD18, C-terminal domain
BTB/POZ domain-containing protein KCTD18 C-terminus

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads KCTD18 as an antibody target. Whether an autoantibody or antibody against KCTD18 could matter depends on whether native KCTD18 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

KCTD18 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 KCTD18 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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