Ro. Heurich et al., GLUCAGON INDUCES A RAPID AND SUSTAINED PHOSPHORYLATION OF THE HUMAN GLUCAGON RECEPTOR IN CHINESE-HAMSTER OVARY CELLS, Biochemical and biophysical research communications, 220(3), 1996, pp. 905-910
The glucagon receptor is a member of the G protein-coupled receptor su
perfamily. Since several G protein-coupled receptors undergo phosphory
lation in response to agonist, we investigated the phosphorylation of
the glucagon receptor following the addition of glucagon to a Chinese
hamster ovary cell line expressing the human glucagon receptor (CHO/hG
R). Glucagon induced a rapid, time and concentration-dependent phospho
rylation of its receptor on serine residues. Neither forskolin nor pho
rbol ester increased receptor phosphorylation, suggesting that cAMP-de
pendent protein kinase and protein kinase C do not catalyze this phosp
horylation event. Furthermore, two mutant cell lines expressing glucag
on receptors with successively truncated receptor cytoplasmic tails we
re tested. A strong correlation between the number of potential phosph
orylation sites, receptor phosphorylation and receptor internalization
was observed, suggesting that phosphorylation of the glucagon recepto
r in CHO/hGR cells is functionally linked to its internalization. (C)
1996 Academic Press, Inc.