Promotilin is a secreted protein that belongs to the motilin family. Human Promotilin cDNA encodes a 115 amino acid (aa) precursor that contains a 25 aa signal peptide and a 90 aa with motilin and motilin-associated peptide. It plays an important role in the regulation of interdigestive gastrointestinal motility and indirectly causes rhythmic contraction of duodenal and colonic smooth muscle.