Seroatlas · Human Serome Atlas

HP1BP3

Heterochromatin protein 1-binding protein 3

Also known as: HP1-BP74, HP1B3_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q5SSJ5
Gene: HP1BP3
Ensembl: ENSG00000127483
Chromosome: 1
Canonical length: 553 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nuclear speckles

OverviewNCBI Gene

Enables DNA binding activity and nucleosome binding activity. Involved in several processes, including cellular response to hypoxia; heterochromatin organization; and regulation of nucleus size. Located in chromosome and nuclear speck. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

553 residues, UniProt reviewed canonical sequence.

>Q5SSJ5|HP1BP3
     1  MATDTSQGEL VHPKALPLIV GAQLIHADKL GEKVEDSTMP IRRTVNSTRE TPPKSKLAEG
    61  EEEKPEPDIS SEESVSTVEE QENETPPATS SEAEQPKGEP ENEEKEENKS SEETKKDEKD
   121  QSKEKEKKVK KTIPSWATLS ASQLARAQKQ TPMASSPRPK MDAILTEAIK ACFQKSGASV
   181  VAIRKYIIHK YPSLELERRG YLLKQALKRE LNRGVIKQVK GKGASGSFVV VQKSRKTPQK
   241  SRNRKNRSSA VDPEPQVKLE DVLPLAFTRL CEPKEASYSL IRKYVSQYYP KLRVDIRPQL
   301  LKNALQRAVE RGQLEQITGK GASGTFQLKK SGEKPLLGGS LMEYAILSAI AAMNEPKTCS
   361  TTALKKYVLE NHPGTNSNYQ MHLLKKTLQK CEKNGWMEQI SGKGFSGTFQ LCFPYYPSPG
   421  VLFPKKEPDD SRDEDEDEDE SSEEDSEDEE PPPKRRLQKK TPAKSPGKAA SVKQRGSKPA
   481  PKVSAAQRGK ARPLPKKAPP KAKTPAKKTR PSSTVIKKPS GGSSKKPATS ARKEVKLPGK
   541  GKSTMKKSFR VKK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against HP1BP3 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): 0.53
Highest tissue expression: 134 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 134 nTPM
ovary: 128 nTPM
thymus: 125 nTPM
cervix: 115 nTPM
blood vessel: 111 nTPM
endometrium: 109 nTPM

Single-cell type

neutrophil progenitors: 397 nCPM
monocyte progenitors: 322 nCPM
myonuclei: 319 nCPM
sertoli cells: 298 nCPM
erythrocyte progenitors: 298 nCPM
lacrimal acinar cells: 257 nCPM

Immune cell

eosinophil: 204 nTPM
basophil: 103 nTPM
naive CD4 T-cell: 81 nTPM
T-reg: 72 nTPM
memory B-cell: 71 nTPM
neutrophil: 67 nTPM

Brain region

white matter: 249 nTPM
basal ganglia: 188 nTPM
cerebral cortex: 181 nTPM
thalamus: 179 nTPM
cerebellum: 179 nTPM
medulla oblongata: 179 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about HP1BP3.

Disease | ImmuneIEDB

Conditions an epitope on HP1BP3 was assayed in.

rheumatoid arthritis B cell

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): 0.3
gnomAD pLI: 0.98
gnomAD missense Z: 2.21
DepMap mean gene effect: 0.04
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

cellular response to hypoxia
heterochromatin organization
nucleosome assembly
regulation of cell population proliferation
regulation of DNA-templated transcription
regulation of nucleus size

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of HP1BP3 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 HP1BP3 as an antibody target. Whether an autoantibody or antibody against HP1BP3 could matter depends on whether native HP1BP3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

HP1BP3 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 HP1BP3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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