Radiation inactivation analysis of progesterone receptor in human uterine cytosol.
It is believed that human progesterone receptor (PR) contains a ligand binding subunit A (83 kDa) or subunit B (120 kDa) and 2 copies of heat shock proteins (hsp90) of molecular weight 90 kDa. To elucidate the mechanism of hormone binding, we employed radiation inactivation to determine its functional size. The functional masses determined in the presence of glycerol, molybdate and potassium chloride were 120+/-14, 124+/-13 and 130+/-20 kDa, respectively. From scatchard plot analysis, the radiation decreased the binding sites and increased the binding affinity of PR with ligand. The functional masses of PR dissolved in the three variant buffers were similar to the molecular weight of PR subunit B. The results implied that PR subunit B could bind with ligand despite hsp90 and hsp90 was not involved in the PR binding to progesterone.
Wu
Chi-Ming
CM
Graduate Institute of Basic Medical Science, Chang Gung University, Taoyuan 333. chimingwu@adm.cgmh.org.tw
Liu
Tse-Jia
TJ
Hsieh
Ling-Ling
LL
Pan
Rong-Long
RL
D003600:Cytosol / Q000737:chemistry; D005260:Female; D005720:Gamma Rays; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D011374:Progesterone / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000528:radiation effects; D017434:Protein Structure, Tertiary / Q000528:radiation effects; D011980:Receptors, Progesterone / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D014599:Uterus / Q000737:chemistry*
D018841:HSP90 Heat-Shock Proteins; D011980:Receptors, Progesterone; D011374:Progesterone