Cloning and characterization of a new subtype of thyrotropin-releasing hormone receptors.
A new subfamily member of thyrotropin releasing hormone (TRH) receptor gene, TRHR2, was isolated from rat brain cDNAs. The deduced amino acid sequence of TRHR2 is 51 % identical to that of rat TRH receptor gene which was reported previously. Northern blot analysis with TRHR2 probe 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.
Itadani
H
H
Banyu Tsukuba Research Institute, Okubo 3, Tsukuba, 300-2611, Japan.
Nakamura
T
T
Itoh
J
J
Iwaasa
H
H
Kanatani
A
A
Borkowski
J
J
Ihara
M
M
Ohta
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D003001:Cloning, Molecular; D018076:DNA, Complementary; D019204:GTP-Binding Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D043562:Receptors, G-Protein-Coupled; D018025:Receptors, Thyrotropin-Releasing Hormone / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D008565:Membrane Proteins; C114581:Mlnr protein, rat; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D018025:Receptors, Thyrotropin-Releasing Hormone; D019204:GTP-Binding Proteins