histamine H4 receptor; HH4R; G-protein coupled receptor 105; GPRv53; SP9144; AXOR35; Pfi-013 (HRH4, GPCR105)

Function: - the H4 subclass of histamine receptors could mediate the histamine signals in peripheral tissues - displays a significant level of constitutive activity (spontaneous activity in the absence of agonist) Structure: belongs to the G-protein coupled receptor 1 family Compartment: cell membrane Expression: - expressed primarily in the bone marrow & eosinophils - preferential expression in cells of immunological relevance such as T-cells, dendritic cells, monocytes, mast cells, neutrophils - also expressed in a wide variety of peripheral tissues, including the heart, kidney, liver, lung, pancreas, skeletal muscle, prostate, small intestine, spleen, testis, colon, fetal liver & lymph node - expression is either up-regulated or down-regulated upon activation of the lymphoid tissues - regulation may depend on the presence of IL-10 or IL-13 Pharmacology: - does not bind diphenhydramine, loratadine, ranitidine, cimetidine or chlorpheniramine - shows shows modest affinity for dimaprit, impromidine, clobenpropit, thioperamide, burimamide clozapine, immepip & imetit - the order of inhibitory activity is imetit > clobenpropit > burimamide > thioperamide - clobenpropit behaves as a partial agonist - dimaprit & impromidine show some agonist activity - clozapine behaves as a full agonist - thioperamide shows inverse agonism (enhances cAMP activity) - the order of inhibitory activity of histamine derivatives was histamine > N-alpha-methylhistamine > R(-)-alpha- methylhistamine > S(+)-alpha-methylhistamine - both N-alpha-methylhistamine > R(-)-alpha-methylhistamine behave as full agonists

General

glycoprotein histamine receptor

Properties

SIZE: MW = 44 kD entity length = 390 aa COMPARTMENT: cellular membrane MOTIF: exoplasmic domain {1-19} MOTIF: N-glycosylation site {N5} N-glycosylation site {N9} transmembrane domain {20-40} cytoplasmic loop {41-52} transmembrane domain {53-73} exoplasmic loop {74-87} MOTIF: cysteine residue {C87} MODIFICATION: cysteine residue {C164} transmembrane domain {88-108} cytoplasmic loop {109-131} transmembrane domain {132-152} exoplasmic loop {153-172} MOTIF: cysteine residue {C164} MODIFICATION: cysteine residue {C87} transmembrane domain {173-193} cytoplasmic loop {194-304} transmembrane domain {305-325} exoplasmic loop {326-341} transmembrane domain {342-362} cytoplasmic domain {363-390} MOTIF: cysteine residue {C374} MODIFICATION: palmitate COMPARTMENT: membrane

Database Correlations

OMIM 606792 UniProt Q9H3N8 Pfam PF00001 Kegg hsa:5934

References

UniProt :accession Q9H3N8