Seroatlas · Human Serome Atlas

TMEM268

Transmembrane protein 268

Also known as: C9orf91, DKFZp547P234, FLJ38045, TM268_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q5VZI3
Gene: TMEM268
Ensembl: ENSG00000157693
Chromosome: 9
Canonical length: 342 aa
Protein class: Predicted membrane proteins
Subcellular location: Plasma membrane,Cytosol

OverviewNCBI Gene

Predicted to be located in plasma membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

342 residues, UniProt reviewed canonical sequence.

>Q5VZI3|TMEM268
     1  MACEPQVDPG ATGPLPPSSP GWSALPGGSP PGWGQELHNG QVLTVLRIDN TCAPISFDLG
    61  AAEEQLQTWG IQVPADQYRS LAESALLEPQ VRRYIIYNSR PMRLAFAVVF YVVVWANIYS
   121  TSQMFALGNH WAGMLLVTLA AVSLTLTLVL VFERHQKKAN TNTDLRLAAA NGALLRHRVL
   181  LGVTDTVEGC QSVIQLWFVY FDLENCVQFL SDHVQEMKTS QESLLRSRLS QLCVVMETGV
   241  SPATAEGPEN LEDAPLLPGN SCPNERPLMQ TELHQLVPEA EPEEMARQLL AVFGGYYIRL
   301  LVTSQLPQAM GTRHTNSPRI PCPCQLIEAY ILGTGCCPFL AR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against TMEM268 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: Cell surface
Secreted: No
Transmembrane segments: 2
Mean surface accessibility (rSASA): 0.37
Highest tissue expression: 20 nTPM

Expression across tissuesHPA

Tissue

cerebral cortex: 20 nTPM
parathyroid gland: 13 nTPM
spleen: 13 nTPM
prostate: 11 nTPM
basal ganglia: 10 nTPM
hippocampal formation: 9.8 nTPM

Single-cell type

retinal pigment epithelial cells: 162 nCPM
prostatic glandular cells: 69 nCPM
pdcs: 49 nCPM
kupffer cells: 44 nCPM
microglia: 37 nCPM
respiratory ionocytes: 36 nCPM

Immune cell

plasmacytoid DC: 4.6 nTPM
naive B-cell: 2.1 nTPM
classical monocyte: 1.3 nTPM
memory B-cell: 1.3 nTPM
intermediate monocyte: 1 nTPM
neutrophil: 1 nTPM

Brain region

cerebral cortex: 43 nTPM
basal ganglia: 31 nTPM
white matter: 31 nTPM
hippocampal formation: 24 nTPM
thalamus: 22 nTPM
choroid plexus: 22 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): 1.24
gnomAD pLI: 0
DepMap mean gene effect: 0.14
DepMap dependency class: none

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

Cellular components

plasma membrane

Protein domainsUniProt · Pfam · InterPro

Protein of unknown function DUF4481
Domain of unknown function (DUF4481)

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of TMEM268 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 TMEM268 as an antibody target. Whether an autoantibody or antibody against TMEM268 could matter depends on whether native TMEM268 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

TMEM268 is annotated at the cell surface, where native TMEM268 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label TMEM268 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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