GPR139, an Orphan Receptor Highly Enriched in the Habenula and Septum, Is Activated by the Essential Amino Acids L-Tryptophan and L-Phenylalanine.
GPR139 is an orphan G-protein-coupled receptor expressed in the central nervous system. To identify its physiologic ligand, we measured GPR139 receptor activity from recombinant cells after treatment with amino acids, orphan ligands, serum, and tissue extracts. GPR139 activity was measured using guanosine 5'-O-(3-[(35)S]thio)-triphosphate binding, calcium mobilization, and extracellular signal-regulated kinases phosphorylation assays. Amino acids L-tryptophan (L-Trp) and L-phenylalanine (L-Phe) activated GPR139, with EC50 values in the 30- to 300-μM range, consistent with the physiologic concentrations of L-Trp and L-Phe in tissues. Chromatography of rat brain, rat serum, and human serum extracts revealed two peaks of GPR139 activity, which corresponded to the elution peaks of L-Trp and L-Phe. With the purpose of identifying novel tools to study GPR139 function, a high-throughput screening campaign led to the identification of a selective small-molecule agonist [JNJ-63533054, (S)-3-chloro-N-(2-oxo-2-((1-phenylethyl)amino)ethyl) benzamide]. The tritium-labeled JNJ-63533054 bound to cell membranes expressing GPR139 and could be specifically displaced by L-Trp and L-Phe. Sequence alignment revealed that GPR139 is highly conserved across species, and RNA sequencing studies of rat and human tissues indicated its exclusive expression in the brain and pituitary gland. Immunohistochemical analysis showed specific expression of the receptor in circumventricular regions of the habenula and septum in mice. Together, these findings suggest that L-Trp and L-Phe are candidate physiologic ligands for GPR139, and we hypothesize that this receptor may act as a sensor to detect dynamic changes of L-Trp and L-Phe in the brain.
Janssen Research & Development LLC, San Diego, California.
Changlu
C
Liu
Janssen Research & Development LLC, San Diego, California Pbonave1@its.jnj.com.
Pascal
P
Bonaventure
Janssen Research & Development LLC, San Diego, California.
Grace
G
Lee
Janssen Research & Development LLC, San Diego, California.
Diane
D
Nepomuceno
Janssen Research & Development LLC, San Diego, California.
Chester
C
Kuei
Janssen Research & Development LLC, San Diego, California.
Jiejun
J
Wu
Janssen Research & Development LLC, San Diego, California.
Qingqin
Q
Li
Janssen Research & Development LLC, San Diego, California.
Victory
V
Joseph
Janssen Research & Development LLC, San Diego, California.
Steven W
SW
Sutton
Janssen Research & Development LLC, San Diego, California.
William
W
Eckert
Janssen Research & Development LLC, San Diego, California.
Xiang
X
Yao
Janssen Research & Development LLC, San Diego, California.
Lynn
L
Yieh
Janssen Research & Development LLC, San Diego, California.
Curt
C
Dvorak
Janssen Research & Development LLC, San Diego, California.
Nicholas
N
Carruthers
Janssen Research & Development LLC, San Diego, California.
Heather
H
Coate
Janssen Research & Development LLC, San Diego, California.
Sujin
S
Yun
Janssen Research & Development LLC, San Diego, California.
Christine
C
Dugovic
Janssen Research & Development LLC, San Diego, California.
Anthony
A
Harrington
Janssen Research & Development LLC, San Diego, California.
Timothy W
TW
Lovenberg
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D057809:HEK293 Cells; D019262:Habenula / Q000737:chemistry*; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000819:agonists / Q000032:analysis / Q000187:drug effects / Q000502:physiology*; D010649:Phenylalanine / Q000097:blood / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000032:analysis / Q000187:drug effects / Q000502:physiology*; D020665:Septum of Brain / Q000737:chemistry*; D014364:Tryptophan / Q000097:blood / Q000502:physiology*
C501535:GPR139 protein, human; D009419:Nerve Tissue Proteins; D043562:Receptors, G-Protein-Coupled; D010649:Phenylalanine; D014364:Tryptophan