Cloning and Characterization of a New Subtype of Thyrotropin-Releasing Hormone Receptors

• Published in: Biochemical and biophysical research communications 1998-09, Vol.250 (1), p.68-71
• Main Authors: Itadani, Hiraku, Nakamura, Takao, Itoh, Junko, Iwaasa, Hisashi, Kanatani, Akio, Borkowski, Joseph, Ihara, Masaki, Ohta, Masataka
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Cloning, Molecular; COS Cells; DNA, Complementary; GTP-Binding Proteins - metabolism; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Molecular Sequence Data; Protein Binding; Rats; Receptors, G-Protein-Coupled; Receptors, Thyrotropin-Releasing Hormone - genetics; RNA, Messenger - genetics; Sequence Homology, Amino Acid
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1998.9268

A new subfamily member of thyrotropin releasing hormone (TRH) receptor gene,TRHR2, was isolated from rat brain cDNAs. The deduced amino acid sequence ofTRHR2is 51 % identical to that of rat TRH receptor gene which was reported previously. Northern blot analysis withTRHR2probe revealed brain-specific expression of a 9.5 kb mRNA. In a binding experiment using the TRHR2-expressing COS cells, specific binding of TRH to TRHR2 was observed with Kd value of 9 nM which was equivalent to the Kd value (= 13 nM) of TRH binding to the TRH receptor previously reported. The active metabolite of TRH, histidyl-proline diketopiperazine, or cyclo(His-Pro), showed no specific binding activity. These results suggest that TRHR2 is a novel subtype of TRH receptor.