Seroatlas · Human Serome Atlas

ZBTB21

Zinc finger and BTB domain-containing protein 21

Also known as: KIAA1227, ZBT21_HUMAN, ZNF295

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

Protein identityUniProt · HPA

UniProt accession: Q9ULJ3
Gene: ZBTB21
Ensembl: ENSG00000173276
Chromosome: 21
Canonical length: 1066 aa
Protein class: Plasma proteins, Predicted intracellular proteins, Transcription factors
Subcellular location: Nucleoplasm
Quaternary structure: Homodimer

OverviewNCBI Gene

Enables several functions, including DNA-binding transcription repressor activity, RNA polymerase II-specific; POZ domain binding activity; and methyl-CpG binding activity. Involved in negative regulation of transcription by RNA polymerase II. Located in cytosol and nucleoplasm. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

1066 residues, UniProt reviewed canonical sequence.

>Q9ULJ3|ZBTB21
     1  MEGLLHYINP AHAISLLSAL NEERLKGQLC DVLLIVGDQK FRAHKNVLAA SSEYFQSLFT
    61  NKENESQTVF QLDFCEPDAF DNVLNYIYSS SLFVEKSSLA AVQELGYSLG ISFLTNIVSK
   121  TPQAPFPTCP NRKKVFVEDD ENSSQKRSVI VCQSRNEAQG KTVSQNQPDV SHTSRPSPSI
   181  AVKANTNKPH VPKPIEPLHN LSLTEKSWPK DSSVVYAKSL EHSGSLDDPN RISLVKRNAV
   241  LPSKPLQDRE AMDDKPGVSG QLPKGKALEL ALKRPRPPVL SVCSSSETPY LLKETNKGNG
   301  QGEDRNLLYY SKLGLVIPSS GSGSGNQSID RSGPLVKSLL RRSLSMDSQV PVYSPSIDLK
   361  SSQGSSSVSS DAPGNVLCAL SQKSSLKDCS EKTALDDRPQ VLQPHRLRSF SASQSTDREG
   421  ASPVTEVRIK TEPSSPLSDP SDIIRVTVGD AATTAAASSS SVTRDLSLKT EDDQKDMSRL
   481  PAKRRFQADR RLPFKKLKVN EHGSPVSEDN FEEGSSPTLL DADFPDSDLN KDEFGELEGT
   541  RPNKKFKCKH CLKIFRSTAG LHRHVNMYHN PEKPYACDIC HKRFHTNFKV WTHCQTQHGI
   601  VKNPSPASSS HAVLDEKFQR KLIDIVRERE IKKALIIKLR RGKPGFQGQS SSQAQQVIKR
   661  NLRSRAKGAY ICTYCGKAYR FLSQFKQHIK MHPGEKPLGV NKVAKPKEHA PLASPVENKE
   721  VYQCRLCNAK LSSLLEQGSH ERLCRNAAVC PYCSLRFFSP ELKQEHESKC EYKKLTCLEC
   781  MRTFKSSFSI WRHQVEVHNQ NNMAPTENFS LPVLDHNGDV TGSSRPQSQP EPNKVNHIVT
   841  TKDDNVFSDS SEQVNFDSED SSCLPEDLSL SKQLKIQVKE EPVEEAEEEA PEASTAPKEA
   901  GPSKEASLWP CEKCGKMFTV HKQLERHQEL LCSVKPFICH VCNKAFRTNF RLWSHFQSHM
   961  SQASEESAHK ESEVCPVPTN SPSPPPLPPP PPLPKIQPLE PDSPTGLSEN PTPATEKLFV
  1021  PQESDTLFYH APPLSAITFK RQFMCKLCHR TFKTAFSLWS HEQTHN

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ZBTB21 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): 0.59
Highest tissue expression: 39 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 39 nTPM
adrenal gland: 34 nTPM
parathyroid gland: 13 nTPM
retina: 13 nTPM
endometrium: 13 nTPM
testis: 11 nTPM

Single-cell type

basal keratinocytes: 62 nCPM
respiratory deuterosomal cells: 60 nCPM
innate lymphoid cells: 57 nCPM
neutrophils: 56 nCPM
suprabasal keratinocytes: 53 nCPM
endometrial stromal cells: 51 nCPM

Immune cell

non-classical monocyte: 3.3 nTPM
intermediate monocyte: 2.8 nTPM
memory B-cell: 2.6 nTPM
naive CD4 T-cell: 2.6 nTPM
classical monocyte: 2.4 nTPM
myeloid DC: 2.4 nTPM

Brain region

hypothalamus: 32 nTPM
midbrain: 32 nTPM
cerebral cortex: 28 nTPM
medulla oblongata: 28 nTPM
thalamus: 27 nTPM
pons: 27 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): 0.25
gnomAD pLI: 1
gnomAD missense Z: 0.51
DepMap mean gene effect: 0.08
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% 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 ZBTB21 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 ZBTB21 as an antibody target. Whether an autoantibody or antibody against ZBTB21 could matter depends on whether native ZBTB21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

ZBTB21 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 ZBTB21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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