Effect of Site Directed Mutagenesis in the CMGCC Region of the .ALPHA.-Subunit on Immunoreactive Human Thyrotropin

KIYOSHI MIYAI, ICHIRO KUMAZAWA, FUMITAKA SAJI, CHIHIRO AZUMA, MASAYASU KOYAMA, TADASHI KIMURA, YOSHIHIDE NARIZUKA, MASAMI KUSUNOKI, YUJI MURATA
1998 Endocrine journal  
The cDNA of the common a-subunit of human glycoprotein hormone was mutated by site directed mutagenesis in the CMGCC region composed of cysteine-methionine-glycine-cysteine-cysteine (position 28-32). The cDNA of wild-type human thyrotropin (hTSH) f3-subunit and that of wild-type or mutant common a-subunits were co-transfected into COS-I cells. The concentration of hTSH determined by two immunoradiometric assay systems was detectable in culture media of COS-I cells transfected with wild-type
more » ... CC) and a mutant (CMGCC) a-subunits but not four other mutants (YMGCC) (CMRCC) (CMACC) (CMGCC). The present data with the other studies on wild-type or mutant glycoprotein hormones support our hypothesis that an amino acid motif of "C-X-G-X-C" in the common a-(CMGCC in human) and fJ-(CAGYC in human) subunits play an important role in biosynthesis of glycoprotein hormones in all species.
doi:10.1507/endocrj.45.467 pmid:9881895 fatcat:djrf5kvrbfhopgrwnu4yp5gb4q