Regulation of Secretory Activation by Akt1 the Fatty Acid Switch

乳腺上皮细胞分化为能够维持哺乳的分泌细胞具有重要意义 对新生儿健康很重要。分泌激活发生在分娩时，标志着晚期 妊娠和哺乳，并依赖Akt。由于糖尿病和肥胖症等疾病 与Aktl活性相关，并对哺乳产生不利影响。了解Akt如何在 分泌激活将为了解由这些疾病引起的哺乳缺陷提供手段。 对这种转变背后的事件的大部分分子分析都集中在牛奶的调节上。 蛋白质基因表达。然而，乳脂提供了支持生长和大脑的关键营养物质。 后代的发育。在分泌激活时发生的依赖AKT的代谢变化包括 葡萄糖转运增加和脂肪生成增加，从而保持牛奶中的脂肪成分不变。我们 假设Akt1是分泌激活的关键遗传调节因子，这在 在这一转变过程中发生的代谢变化。我们设计了三个具体的目标来检验这一假设：1)我们 将确定乳腺上皮特异的基因，其表达受Aktl在 利用qPCR和全局表达阵列进行分泌分化和激活。2)我们将测试这些Akt 依赖调节因子恢复成脂分化和分泌激活的能力 乳腺上皮细胞株的体外培养和体内Aktl缺失乳腺上皮细胞的培养。我们将确定是否 这些基因中的任何一个都可以刺激脂肪酸的生物合成，在缺乏 分化刺激。3)我们将确定乳腺上皮特异的磷酸化蛋白底物 利用多个蛋白质组研究成脂分化和分泌激活所必需的AktL 识别磷酸化蛋白质的平台。累积起来，Akt1依赖基因的鉴定， 加上Aktl依赖的蛋白质底物，将使我们能够阐明正常乳腺上皮的功能 阿克特尔。我们最终将为加强下列妇女的哺乳障碍提供坚实的基础 患有糖尿病和/或肥胖症。 相关性(请参阅说明)： Aktl在妊娠和哺乳期调节乳腺上皮细胞的成脂分化；然而， 它还整合了细胞生存、增殖和能量代谢的信号。因为Aktl是由 糖尿病和肥胖症，它整合了正常和异常刺激，调节乳腺功能。 了解Akt的功能可能会改善肥胖和糖尿病女性的哺乳期。

The differentiation of mammary epithelial cells into secretory cells capable of sustaining lactation is of great mportance to newborn health. Secretory activation occurs at parturition, marks the transition between late pregnancy and lactation, and is dependent on Akt. Since diseases such as diabetes and obesity are correlated with Aktl activity and adversely effect lactation. Understanding how Akt functions normally during secretory activation will provide the means to understand lactation defects resulting from these disorders. Much of the molecular analysis of events that underlie this transition has focused upon the regulation of milk protein gene expression. However, milk fat provides the crucial nutrient that supports both growth and brain development of the offspring. Akt dependent metabolic changes that occur at secretory activation include increased glucose transport and elevated lipogenesis that maintain a constant fat composition in milk. We hypothesize that Aktl is a critical genetic regulator of secretory activation that is particularly important in the metabolic switch that occurs at this transition. Three specific aims are designed to test this hypothesis: 1) We will identify genes specific to the mammary epithelium whose expression is regulated by Aktl during secretory differentiation and activation using qPCR and global expression arrays. 2) We will test these Akt dependent regulators for ability to restore lipogenic differentiation and secretory activation in established mammary epithelial cell lines in vitro and in Aktl null mammary epithelium in vivo. We will determine whether any of these genes can stimulate fatty acid biosynthesis to form cytoplasmic lipid droplets in the absence of differentiation stimuli. 3) We will identify mammary epithelium specific phosphorylated protein substrates for Aktl that are necessary for lipogenic differentiation and secretory activation by using multiple proteomic platforms that identify phosphorylated proteins. Cumulatively, the identification of Aktl dependent genes, plus Aktl dependent protein substrates, will allow us to elucidate normal mammary epithelium function of Aktl. We ultimately will provide a strong foundation toward enhancing the impaired lactation of women who are afflicted by diabetes and/or obesity. RELEVANCE (See instructions): Aktl regulates lipogenic differentiation of mammary epithelial cells during pregnancy and lactation; however, it also integrates signals for cell survival, proliferation, and energy metabolism. Because Aktl is activated by diabetes and obesity, it integrates both normal and abnormal stimuli to modulate mammary gland function. Understanding how Akt functions may improve lactation in obese and diabetic women.