Heregulin Beta 1 Enhances Nuclear Localization of BRCA1

描述（由申请人提供）：Heregulin （HRG）是一种调节生长、分化和生存的生长因子。Heregulin通过直接结合ErbB受体刺激信号通路。heregulin的下游靶点信号通路包括Ras/ERK通路和PI3K/Akt通路。Altiok等人证明，当heregulin处理乳腺癌细胞时，BRCA1通过PI3K/AKT通路被磷酸化（Altiok等）。BRCA1是一种细胞周期调控的肿瘤抑制因子，在多个氨基酸上被磷酸化。据报道，BRCA1对DNA损伤的磷酸化会改变蛋白质的亚细胞定位状态（Ruffner, et al. 1999）。然而，生长因子诱导的BRCA1磷酸化对其亚细胞定位的影响尚未被研究。因此，本项目将测试PI3K/Akt磷酸化BRCA1与亚细胞定位的相关性。假设：Heregulin- beta1通过PI3K/Akt通路增强BRCA1的核定位。

DESCRIPTION (provided by applicant): Heregulin (HRG) is a growth factor that regulates growth, differentiation, and survival. Heregulin stimulates signaling pathways through direct binding to the ErbB receptors. Signaling pathways that are downstream targets of heregulin include the Ras/ERK pathway, and the PI3K/Akt pathway. Altiok et al demonstrated that when breast cancer cells are treated with heregulin, BRCA1 is phosphorylated through the PI3K/AKT pathway (Altiok, et al). BRCA1 is a cell cycle-regulated tumor suppressor that is phosphorylated at multiple amino acids. It has been reported that phosphorylation of BRCA1 in response to DNA damage changes the subcellular localization state of the protein (Ruffner, et al. 1999). However, the effects of phosphorylation of BRCA1 induced by a growth factor on its subcellular localization have not been investigated. Therefore, this project will test the correlation of phosphorylation of BRCA1 by PI3K/Akt and subcellular localization. The hypothesis is: Heregulin- beta1 enhances BRCA1 nuclear localization through the PI3K/Akt pathway.