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Steroid hormone antagonists at the receptor level: A role for the heat‐shock protein MW 90,000 (hsp 90)
Author(s) -
Baulieu EtienneEmile
Publication year - 1987
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240350209
Subject(s) - receptor , hormone , heat shock protein , hormone receptor , microbiology and biotechnology , biology , hormone response element , chemistry , gene , endocrinology , biochemistry , genetics , estrogen receptor , cancer , breast cancer
Antisteroid hormones compete for hormone binding at the receptor level and prevent the hormonal response. A new concept is proposed for explaining the antiglucocorticosteroid activity of RU 486 in the chick oviduct system. It is based on the ability of the antisteroid to stabilize the hetero‐oligomeric 8S‐form of the glucocorticosteroid receptor (GR), which involves the interaction of the 94k‐receptor and heat‐shock protein MW 90,000 (hsp 90). It is proposed that hsp 90 caps the DNA binding site of the receptor, and this prevents it from binding to the DNA of hormone regulatory elements (HRE) and increasing transcription of regulated genes. This paper reviews other antiglucocorticosteroid and antiestrogen systems with reference to this hypothesis and also describes a four‐step analysis of the molecular mechanism of antisteroid hormone action at the receptor level.