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FLASH GENE
Symbol HP contributors: mct/npt - updated : 17-12-2009
HGNC name haptoglobin
HGNC id 5141
EXPRESSION
Type restricted
constitutive of
   expressed in (based on citations)
organ(s)
SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
Digestiveliver   highly
Reproductivefemale systemovary   
Visualeyeanterior segmentcornea  
tissue
SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
Muscularstriatumskeletal  
cell lineage
cell lines
fluid/secretion
at STAGE
PROTEIN
PHYSICAL PROPERTIES
STRUCTURE
motifs/domains
  • N-terminal AA sequence has striking similarities to the light chain of human gamma-globulins (Tripathi 2009)
  • a short consensus repeat
  • a peptidase S1 domain
  • growth factor-like repeats
  • 2 sushi structures (see F13B, SRCP1)
  • only the beta-chain of haptoglobin is involved in receptor recognition (Cd163) (Nielsen 2007)
  • secondary structure
  • mature HPs are heterodimeric plasma glycoproteins composed of alpha- and beta-polypeptide chains that are covalently associated by disulfide bonds and in which only the beta-chain is glycosylated (Tripathi 2009)
  • conjugated GlycoP
    mono polymer heteromer , tetramer
    isoforms Precursor including alpha (1 or 2,84/143AAs) and beta chains (244AAs)
    HOMOLOGY
    interspecies homolog to murine Hp
    Homologene
    FAMILY
  • peptidase S1 family
  • CATEGORY transport carrier
    SUBCELLULAR LOCALIZATION extracellular
    basic FUNCTION
  • combines with free plasma hemoglobin, preventing loss of iron through the kidneys and protecting the kidneys from damage by hemoglobin, while making the hemoglobin accessible to degradative enzymes
  • binds the apolipoprotein (Apo) A-I domain, which is involved in stimulating the enzyme lecithin-cholesterol acyltransferase (LCAT) for cholesterol esterification (Salvatore 2009)
  • protects Hb when oxidatively challenged with H(2)O(2) preserving CD163-mediated Hb clearance under oxidative stress conditions (Buehler 2009)
  • CELLULAR PROCESS
    PHYSIOLOGICAL PROCESS
    PATHWAY
    metabolism
    signaling
    a component
  • heterotetramer alpha 2/beta 2 complexing with free oxyhemoglobin to be removed and degraded in liver
  • dimer of alphabeta-chains covalently linked by a disulphide bond between the Cys15 residue of each alpha-chain (Polticelli 2008)
  • INTERACTION
    DNA
    RNA
    small molecule
    protein
  • binding free oxyhemoglobin
  • cell & other
    REGULATION
    ASSOCIATED DISORDERS
    corresponding disease(s) HP
    Susceptibility
    Variant & Polymorphism
    Candidate gene
    Marker
    Therapy target
    ANIMAL & CELL MODELS