MLNR | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
Aliases | MLNR , GPR38, MTLR1, motilin receptor | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 602885; HomoloGene: 74398; GeneCards: MLNR; OMA:MLNR - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Motilin receptor is a G protein-coupled receptor (previously GPCR38) [3] [4] [5] that binds motilin. [6] [7] It was first cloned in 1999 by Merck Laboratories. [8] and scientists have since been searching for compounds to modify its behavior. [9]
The primary structure of the motilin receptor consists of 412 amino acids, [8] while its tertiary structure resembles a golf club. [10] The protein C-terminal protein protects from enzymatic degradation, while the N-terminal is essential for binding. [10]
The primary function of the motilin receptor is to contract gastric smooth muscle during phase III of the migrating motor complex (MMC). [8] In this final phase of the MMC, N-type motilin receptors in the distal antral pump of the stomach are activated. [11] This causes contraction of the gastric smooth muscle, sieving food into the small intestine, and priming the stomach for the next meal. [12]
Motilin is an intestinal peptide that stimulates the contraction of gastric smooth muscle via the motilin receptor. [8] It is produced by enteroendocrine cells in the proximal small intestine [3] [13] and secreted cyclically. [14] Motilin mimetics could be used to increase gastric motility in patients with gastroparesis e.g., constipation-predominant irritable bowel syndrome. [15] However, none of the candidate drugs that have been tested so far have made it to market. [4] [16]