Bombesin-like receptor 3
Encyclopedia
The bombesin receptor subtype 3 also known as BRS-3 or BB3 is a protein
which in humans is encoded by the BRS3 gene
.
-like peptides are widely distributed in the central nervous system
as well as in the gastrointestinal tract
, where they modulate smooth-muscle contraction, exocrine and endocrine processes, metabolism, and behavior. They bind to G protein-coupled receptors on the cell surface to elicit their effects. Bombesin-like peptide receptors include gastrin-releasing peptide receptor
, neuromedin B receptor
, and bombesin-like receptor-3 (BRS3; this article).
BB3 is a G protein-coupled receptor
. BB3 only interacts with known naturally-occurring bombesin-related peptides with low affinity and therefore, as it has no natural high-affinity ligand, is classified as an orphan receptor
.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
which in humans is encoded by the BRS3 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
Function
Mammalian bombesinBombesin
Bombesin is a 14-amino acid peptide originally isolated from the skin of a frog. It has two known homologs in mammals called neuromedin B and gastrin-releasing peptide. It stimulates gastrin release from G cells. It activates three different G-protein-coupled receptors known as BBR1, -2, and -3. It...
-like peptides are widely distributed in the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
as well as in the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
, where they modulate smooth-muscle contraction, exocrine and endocrine processes, metabolism, and behavior. They bind to G protein-coupled receptors on the cell surface to elicit their effects. Bombesin-like peptide receptors include gastrin-releasing peptide receptor
Gastrin-releasing peptide receptor
The gastrin-releasing peptide receptor , now properly known as BB2 is a G protein-coupled receptor whose endogenous ligand is gastrin releasing peptide...
, neuromedin B receptor
Neuromedin B receptor
The neuromedin B receptor , now known as BB1 is a G protein-coupled receptor whose endogenous ligand is neuromedin B ....
, and bombesin-like receptor-3 (BRS3; this article).
BB3 is a G protein-coupled receptor
G protein-coupled receptor
G protein-coupled receptors , also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors , comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal...
. BB3 only interacts with known naturally-occurring bombesin-related peptides with low affinity and therefore, as it has no natural high-affinity ligand, is classified as an orphan receptor
Orphan receptor
An orphan receptor is an apparent receptor that has a similar structure to other identified receptors but whose endogenous ligand has not yet been identified. If a ligand for an orphan receptor is later discovered, the receptor is referred to as an "adopted orphan".-Examples:Examples of orphan...
.