Seroatlas · Human Serome Atlas

TMEM18

Transmembrane protein 18

Also known as: DKFZp434C1714, lncND, TMM18_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q96B42
Gene: TMEM18
Ensembl: ENSG00000151353
Chromosome: 2
Canonical length: 140 aa
Protein class: Predicted membrane proteins, Transporters
Subcellular location: Endoplasmic reticulum,Mitochondria
Quaternary structure: Homooligomer

OverviewNCBI Gene

Predicted to enable DNA binding activity. Involved in cell migration. Located in nuclear membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

140 residues, UniProt reviewed canonical sequence.

>Q96B42|TMEM18
     1  MPSAFSVSSF PVSIPAVLTQ TDWTEPWLMG LATFHALCVL LTCLSSRSYR LQIGHFLCLV
    61  ILVYCAEYIN EAAAMNWRLF SKYQYFDSRG MFISIVFSAP LLVNAMIIVV MWVWKTLNVM
   121  TDLKNAQERR KEKKRRRKED

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against TMEM18 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: 3
Mean surface accessibility (rSASA): 0.37
Highest tissue expression: 31 nTPM

Expression across tissuesHPA

Tissue

ovary: 31 nTPM
skeletal muscle: 25 nTPM
pancreas: 22 nTPM
spinal cord: 20 nTPM
blood vessel: 19 nTPM
adrenal gland: 18 nTPM

Single-cell type

oocytes: 111 nCPM
esophageal apical cells: 104 nCPM
early primary spermatocytes: 99 nCPM
epididymal principal cells: 99 nCPM
syncytiotrophoblasts: 97 nCPM
ovarian stromal cells: 94 nCPM

Immune cell

plasmacytoid DC: 22 nTPM
NK-cell: 19 nTPM
memory B-cell: 19 nTPM
non-classical monocyte: 19 nTPM
T-reg: 17 nTPM
myeloid DC: 17 nTPM

Brain region

white matter: 11 nTPM
hypothalamus: 9.9 nTPM
pons: 9.5 nTPM
medulla oblongata: 9.3 nTPM
cerebral cortex: 8.8 nTPM
midbrain: 8.7 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): 1.32
gnomAD pLI: 0
gnomAD missense Z: 0.01
DepMap mean gene effect: 0.01
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

DNA binding

Cellular components

Protein domainsUniProt · Pfam · InterPro

Transmembrane protein 18
Transmembrane protein 18

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads TMEM18 as an antibody target. Whether an autoantibody or antibody against TMEM18 could matter depends on whether native TMEM18 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

TMEM18 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 TMEM18 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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