Seroatlas · Human Serome Atlas

HPR

Haptoglobin-related protein

Also known as: HPTR_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: P00739
Gene: HPR
Ensembl: ENSG00000261701
Chromosome: 16
Canonical length: 348 aa
Protein class: Enzymes, Plasma proteins, Predicted secreted proteins
Subcellular location: Vesicles
Secretome location: Secreted to blood

OverviewNCBI Gene

This gene encodes a haptoglobin-related protein that binds hemoglobin as efficiently as haptoglobin. Unlike haptoglobin, plasma concentration of this protein is unaffected in patients with sickle cell anemia and extensive intravascular hemolysis, suggesting a difference in binding between haptoglobin-hemoglobin and haptoglobin-related protein-hemoglobin complexes to CD163, the hemoglobin scavenger receptor. This protein may also be a clinically important predictor of recurrence of breast cancer. [provided by RefSeq, Oct 2011]

Canonical amino-acid sequenceUniProt

348 residues, UniProt reviewed canonical sequence.

>P00739|HPR
     1  MSDLGAVISL LLWGRQLFAL YSGNDVTDIS DDRFPKPPEI ANGYVEHLFR YQCKNYYRLR
    61  TEGDGVYTLN DKKQWINKAV GDKLPECEAV CGKPKNPANP VQRILGGHLD AKGSFPWQAK
   121  MVSHHNLTTG ATLINEQWLL TTAKNLFLNH SENATAKDIA PTLTLYVGKK QLVEIEKVVL
   181  HPNYHQVDIG LIKLKQKVLV NERVMPICLP SKNYAEVGRV GYVSGWGQSD NFKLTDHLKY
   241  VMLPVADQYD CITHYEGSTC PKWKAPKSPV GVQPILNEHT FCVGMSKYQE DTCYGDAGSA
   301  FAVHDLEEDT WYAAGILSFD KSCAVAEYGV YVKVTSIQHW VQKTIAEN

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against HPR 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.32
Highest tissue expression: 759 nTPM

Expression across tissuesHPA

Tissue

liver: 759 nTPM
heart muscle: 129 nTPM
midbrain: 15 nTPM
basal ganglia: 15 nTPM
amygdala: 11 nTPM
blood vessel: 11 nTPM

Single-cell type

hepatocytes: 318 nCPM
cardiomyocytes: 24 nCPM
mesothelial cells: 13 nCPM
cholangiocytes: 11 nCPM
schwann cells: 7.8 nCPM
epicardial cells: 6.8 nCPM

Immune cell

plasmacytoid DC: 0.6 nTPM
T-reg: 0.6 nTPM
naive CD4 T-cell: 0.4 nTPM
gdT-cell: 0.2 nTPM
intermediate monocyte: 0.2 nTPM
naive B-cell: 0.2 nTPM

Brain region

basal ganglia: 8.6 nTPM
thalamus: 8.5 nTPM
midbrain: 7.1 nTPM
medulla oblongata: 7 nTPM
hypothalamus: 6.8 nTPM
amygdala: 6.5 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): 1.6
gnomAD pLI: 0
gnomAD missense Z: -1.52
DepMap mean gene effect: 0.07
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

zymogen activation

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

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

HPR is annotated as secreted, so native HPR circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

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

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