Takahashi S, Odani N, Tomokiyo K, Furuta K, Suzuki M, Ichikawa A, Negishi M
Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Biochem J. 1998 Oct 1;335 ( Pt 1)(Pt 1):35-42. doi: 10.1042/bj3350035.
Cyclopentenone prostaglandins (PGs) are transported into cells and stimulate the expression of various stress genes, such as that coding for BiP (an ER luminal protein). To reveal the site of action of the PGs for the induction of stress-gene expression, we introduced a fluorescent probe, pyrene, into two types of PG analogue, GIF0010 (a cyclopentenone type) and GIF0037 (a cyclopentanone type) and examined their intracellular localization in normal rat kidney cells and their ability to induce the BiP gene expression. GIF0010 accumulated around the nuclei and coincided with BiP, a resident protein in the endoplasmic reticulum (ER) and markedly induced BiP gene expression. By contrast, GIF0037 and pyrene neither accumulated in the cell nor induced BiP gene expression. Thus the ER localization of GIF0010 and the induction of gene expression by GIF0010 are ascribed to the cyclopentenone structure. Treatment with cycloheximide inhibited both the accumulation of GIF0010 and the induction of the BiP mRNA, suggesting that the ER localization of the PG and subsequent gene expression require the nascent protein synthesis. These results demonstrate that the cyclopentenone PG is specifically accumulated in the ER, transducing a signal for BiP gene expression in the nuclei.
环戊烯酮前列腺素（PGs）被转运进入细胞并刺激各种应激基因的表达，比如编码BiP（一种内质网腔蛋白）的基因。为了揭示PGs诱导应激基因表达的作用位点，我们将荧光探针芘引入两种PG类似物GIF0010（环戊烯酮型）和GIF0037（环戊酮型）中，并检测它们在正常大鼠肾细胞中的细胞内定位以及诱导BiP基因表达的能力。GIF0010在细胞核周围聚集，与内质网（ER）中的驻留蛋白BiP相符，并显著诱导BiP基因表达。相比之下，GIF0037和芘既不聚集在细胞内，也不诱导BiP基因表达。因此，GIF0010的内质网定位以及GIF0010对基因表达的诱导归因于环戊烯酮结构。用环己酰亚胺处理可抑制GIF0010的聚集和BiP mRNA的诱导，这表明PG的内质网定位及随后的基因表达需要新生蛋白质合成。这些结果表明，环戊烯酮PG特异性地在内质网中积累，传递细胞核中BiP基因表达的信号。
