Apelin (APLN)

Apelin also known as APLN is a peptide which is encoded by the APLN gene. Apelin is the endogenous ligand for the G-protein-coupled APJ receptor that is expressed at the surface of some cell types. It is widely expressed in various organs such as the heart, lung, kidney, liver, adipose tissue,gastrointestinal tract, brain, adrenal glands, endothelium, and human plasma.

The gene encodes a 77-amino acid polypeptide that includes a secretory signal sequence. Synthetic 36-amino acid apelin (apelin-36), corresponding to the most C-terminal 36 residues of preproapelin, caused the acidification of cells expressing transfected APJ, but not other receptors. Apelin is an endogenous ligand for the APJ receptor.