%0 Journal Article
%T Mutagenesis of GPR139 reveals ways to create gain or loss of function receptors
%A Amy Shih
%A Changlu Liu
%A Chester Kuei
%A Diane Nepomuceno
%A Frances Fan
%A Grace Lee
%A Jiejun Wu
%A Lien Wang
%A Michelle Wennerholm
%A Pascal Bonaventure
%A Timothy W. Lovenberg
%J Archive of "Pharmacology Research & Perspectives".
%D 2019
%R 10.1002/prp2.466
%X GPR139 is a Gqİ\coupled receptor activated by the essential amino acids Lİ\tryptophan (Lİ\Trp) and Lİ\phenylalanine (Lİ\Phe). We carried out mutagenesis studies of the human GPR139 receptor to identify the critical structural motifs required for GPR139 activation. We applied siteİ\directed and high throughput random mutagenesis approaches using a double addition normalization strategy to identify novel GPR139 sequences coding receptors that have altered sensitivity to endogenous ligands. This approach resulted in GPR139 clones with gainİ\ofİ\function, reductionİ\ofİ\function or lossİ\ofİ\function mutations. The agonist pharmacology of these mutant receptors was characterized and compared to wildİ\type receptor using calcium mobilization, radioligand binding, and protein expression assays. The structureİ\activity data were incorporated into a homology model which highlights that many of the gainİ\ofİ\function mutations are either in or immediately adjacent to the purported orthosteric ligand binding site, whereas the lossİ\ofİ\function mutations were largely in the intracellular Gİ\protein binding area or were disrupters of the helix integrity. There were also some reductionİ\ofİ\function mutations in the orthosteric ligand binding site. These findings may not only facilitate the rational design of novel agonists and antagonists of GPR139, but also may guide the design of transgenic animal models to study the physiological function of GPR139
%K calcium mobilization assay
%K gain of function
%K GPR139
%K homology model
%K random mutagenesis
%K reduction of function
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6367278/