HRH2

Histamine is a ubiquitous messenger molecule released from mast cells, enterochromaffin-like cells, and neurons. Its various actions are mediated by histamine receptors H1, H2, H3 and H4. Histamine receptor H2 belongs to the family 1 of G protein-coupled receptors. It is an integral membrane protein and stimulates gastric acid secretion. It also regulates gastrointestinal motility and intestinal secretion and is thought to be involved in regulating cell growth and differentiation. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Aug 2008]

Full Name

Histamine Receptor H2

Function

The H2 subclass of histamine receptors mediates gastric acid secretion. Also appears to regulate gastrointestinal motility and intestinal secretion. Possible role in regulating cell growth and differentiation. The activity of this receptor is mediated by G proteins which activate adenylyl cyclase and, through a separate G protein-dependent mechanism, the phosphoinositide/protein kinase (PKC) signaling pathway (By similarity).

Biological Process

Chemical synaptic transmission Source: GO_Central
Gastric acid secretion Source: InterPro
G protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messenger Source: GO_Central
Immune response Source: ProtInc
Positive regulation of vasoconstriction Source: InterPro

Cellular Location

Cell membrane

Topology

Extracellular: 1-22
Helical: 23-44
Cytoplasmic: 45-57
Helical: 58-81
Extracellular: 82-92
Helical: 93-114
Cytoplasmic: 115-134
Helical: 135-159
Extracellular: 160-180
Helical: 181-204
Cytoplasmic: 205-234
Helical: 235-258
Extracellular: 259-267
Helical: 268-289
Cytoplasmic: 290-359