title: Production of n-octanoyl-modified ghrelin in cultured cells requires prohormone processing protease and ghrelin O-acyltransferase, as well as n-octanoic acid.
abstract: Ghrelin was originally isolated from rat stomach as an endogenous ligand for the GH secretagogue receptor. The major active form of ghrelin is a 28-amino acid peptide modified by an n-octanoic acid on the serine 3 residue, and this lipid modification is essential for the biological activity of ghrelin. However, it is not clear whether prohormone convertase (PC) and ghrelin O-acyltransferase (GOAT) are the minimal requirements for synthesis of acyl-modified ghrelin in cultured cells. By using three cultured cell lines, TT, AtT20 and COS-7, in which the expression levels of processing proteases and GOAT vary, we examined the processing patterns of ghrelin precursor. We found that not only PC1/3 but also both PC2 and furin could process proghrelin to the 28-amino acid ghrelin. Moreover, the presence of PC and GOAT in the cells, as well as n-octanoic acid in the culture medium, was necessary to produce n-octanoyl ghrelin.
authors.affiliation: Molecular Genetics, Institute of Life Science, Kurume University, Kurume, Fukuoka 839-0864, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Takahashi
authors.forename: Takanori
authors.initials: T
authors.lastname: Ida
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sato
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Akihiko
authors.initials: A
authors.lastname: Tsuji
authors.forename: Masayasu
authors.initials: M
authors.lastname: Kojima
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002210:Caprylates / Q000378:metabolism*; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D005215:Fasting; D045683:Furin / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D005822:Genetic Vectors / Q000235:genetics; D054439:Ghrelin / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D043484:Proprotein Convertases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013270:Stomach / Q000201:enzymology; D014162:Transfection
chemical_list: D002210:Caprylates; D054439:Ghrelin; D012333:RNA, Messenger; C422650:ghrelin, des-n-octanoyl; D000217:Acyltransferases; D043484:Proprotein Convertases; D045683:Furin; C031492:octanoic acid