Her Song, Patel Paresh D, Schatzberg Alan F, Lyons David M
Department of Psychiatry, Stanford University Medical Center, Stanford, CA 94305-5485, USA.
J Steroid Biochem Mol Biol. 2005 Mar;94(4):319-26. doi: 10.1016/j.jsbmb.2004.11.010. Epub 2005 Feb 24.
To identify the determinants of impaired glucocorticoid receptor (GR) signaling in a model of glucocorticoid resistance, cloned GR from Guyanese squirrel monkeys (gsmGR) was tagged with enhanced green fluorescent protein, and nuclear translocation was examined in transfected COS1 cells. In keeping with evidence that gsmGR transactivational competence is impaired, we found that nuclear translocation is likewise diminished in gsmGR relative to human GR (hGR). Experiments with GR chimeras revealed that replacement of the gsmGR ligand binding domain (LBD) with that from hGR increased translocation. Truncated gsmGR constructs lacking the LDB after amino acid 552 also showed increased translocation even in the absence of cortisol. Three back-mutations of gsmGR to hGR (Thr551Ser, Ala616Ser, and Ser618Ala) in the LBD confirmed that these amino acids play a role in diminished translocation.
为了在糖皮质激素抵抗模型中确定糖皮质激素受体（GR）信号受损的决定因素，将来自圭亚那松鼠猴的克隆GR（gsmGR）用增强型绿色荧光蛋白进行标记，并在转染的COS1细胞中检测核转位。与gsmGR反式激活能力受损的证据一致，我们发现相对于人类GR（hGR），gsmGR中的核转位同样减少。GR嵌合体实验表明，用hGR的配体结合域（LBD）替换gsmGR的LBD可增加转位。即使在没有皮质醇的情况下，缺少552位氨基酸后LDB的截短gsmGR构建体也显示出转位增加。LBD中gsmGR到hGR的三个反向突变（Thr551Ser、Ala616Ser和Ser618Ala）证实这些氨基酸在转位减少中起作用。
