HRH4 HRH4 (histamine receptor H4)
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Multi-pass
Bone Marrow
Eosinophil
Pancreas
Dendritic Cell
Monocyte
Neutrophil
Heart
Kidney
Liver
Lung
Skeletal muscle
Small intestine
Lymph Node
Peripheral blood
Thymus
Leukocyte

Expression
HRH4 is expressed primarily in the bone marrow and eosinophils.  It shows preferential distribution in cells in immunological relevance as T cell, dendritic cells, monocytes, peripheral blood leukocytes and neutrophils.  Expression is in a wide variety of peripheral tissues including the heart, kidney, liver, lung, pancreas, skeletal muscle, thymus, prostate, small intestine, fetal liver and lymph node.  Expression is either up-regulated or down-regulated upon activation of the lymphoid tissues and this regulation may depend on the presence of IL-10 or IL-13.

Structure
MOLECULAR FAMILY NAME: Belongs to the G-protein coupled receptor family.

HRH4 is a multi-pass 390 aa glycoprotein.  In contains an extracellular domain, a transmembrane domain which contains an asp residue in TM1, a DRY motif in TM2, a disulfide bond between the first and third extracellular loops, a trp in TM4 and TM6, a pro in TM5 and TM6 and a NPxxY motif in TM7 and a C-terminal cytoplasmic domain which contains a potential palmitoylation site.  Various actions are mediated by histamine receptors H1, H2, H3 and H4.  HRH4 (histamine receptor H4) belongs to the family 1 of G-protein coupled receptors and has the highest homology to histamine recepotor H3 among known G-protein coupled receptors.  HRH4 amino acid is almost 40% identical to HRH3.

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION: No information.

Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH HRH4: No information.

Function

Histamine is a ubiquitous messenger molecule released from mast cells, enterochromaffin-like cells and neurons.  The H4 subclass of histamine receptors could mediate the histamine signals in perpheral tissues.  HRH4 displays a significant level of constitutive activity and spontaneous activity in the absence of agonist.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF HRH4 IN INTACT ANIMAL

HRH4 may mediate signals in peripheral tissues and thus have a somewhat different physiology, particularly in immune regulation and inflammatory processes.  It is suggested that different agonists and antogonists will be required for therapy and biologic anlaysis.



Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF HRH4: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY HRH4: No information.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene59340Q9H3N8
Antibodies

Revised June 25, 2008


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