THE ROLES OF PROHIBITINS (PHBS) IN 3T3-L1 ADIPOCYTE DIFFERENTIATION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 A.具体目标 本研究的目的是确定抑制素在3T3-L1脂肪细胞分化过程中的功能意义。我们的初步数据显示，在3T3-L1前脂肪细胞的脂肪细胞分化过程中，这两种抑制素(PHBs)，包括PHB1和PHB2(雌激素受体活性抑制因子，REA)，都显著增加。此外，siRNA-PHB1或siRNA-REA同时下调PHBs蛋白后，3T3-L1脂肪细胞的分化受到抑制。因此，我们的第一个目标是研究PHBs在脂肪形成过程中的作用机制(磷酸化和亚细胞转位)。基于生物信息学分析，我们在小鼠和人PHBs启动子中发现了几个推测的Egr-1转录因子结合位点。此外，我们观察到，在3T3-L1脂肪细胞分化过程中，Egr-1的表达先于PHBs的增加而被诱导。此外，在脂肪转基因Egr-1小鼠的脂肪组织中，PHBs蛋白的表达上调。我们的第二个目标是确定Egr-1是3T3-L1脂肪细胞分化过程中PHBs上调的关键调节器。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A. Specific Aims The goal of this proposal is to determine the functional significance of prohibitins during 3T3-L1 adipocyte differentiation. Our preliminary data showed that both of these prohibitins (PHBs), including PHB1 and PHB2 (repressor of estrogen receptor activity, REA), were significantly increased during the adipocyte differentiation of 3T3-L1 preadipocytes. Moreover, 3T3-L1 adipocyte differentiation was impaired after the simultaneous knockdown of either PHBs protein by siRNA-PHB1 or siRNA-REA. So, our first aim is to examine the functional mechanism (phosphorylation and subcellular translocation) of PHBs during adipogenesis. Based on the bioinformatics analyses, we found several putative Egr-1 transcription factor binding sites in the mouse and human PHBs promoters. In addition, we observed that Egr-1 expression was induced prior to the increase of PHBs during 3T3-L1 adipocyte differentiation. Furthermore, the expression of PHBs proteins was upregulated in the adipose tissue in adipose-transgenic Egr-1 mice. Our second aim is to determine that Egr-1 is a critical modulator of PHBs upregulation during 3T3-L1 adipocyte differentiation.