通过去泛素化酶 OTUB2 调控 Gli2 的稳定性。
Regulation of Gli2 stability by deubiquitinase OTUB2.
机构信息
King's Lab, School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China; Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
King's Lab, School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
出版信息
Biochem Biophys Res Commun. 2018 Oct 20;505(1):113-118. doi: 10.1016/j.bbrc.2018.09.071. Epub 2018 Sep 19.
The transcription factor Gli2 plays crucial roles in the transduction of Hedgehog (Hh) signals, yet the mechanisms that control Gli2 degradation remain unclear. Here we have identified the eubiquitinating enzyme otubain2 (OTUB2) as a regulator of Gli2 protein degradation. We found that OTUB2 was coimmunoprecipitated with Gli2. Knockdown of OTUB2 decreased Gli2 protein level while the proteasome inhibitor MG-132 treatment restored Gli2 expression. Additionally, OTUB2 overexpression stabilized Gli2 protein in U2OS cells and extended the half-life of Gli2. We also found that knockdown of OTUB2 reduced deubiquitination of Gli2 in vivo. In vitro deubiquitination assay showed that ubiquitinated Gli2 was decreased by wild-type OTUB2 but not OTUB2 mutations. We also found that OTUB2 knockdown suppressed the ALP activity and the expression of the common markers BMP2 and RUNX2 during osteogenesis of MSCs in response to Shh and Smo agonists, which indicated OTUB2 may have effect on osteogenic differentiation by regulating Hh signaling.
转录因子 Gli2 在 Hedgehog(Hh)信号转导中发挥着关键作用,但控制 Gli2 降解的机制仍不清楚。在这里,我们已经确定泛素连接酶 otubain2(OTUB2)是 Gli2 蛋白降解的调节因子。我们发现 OTUB2 与 Gli2 共免疫沉淀。OTUB2 的敲低降低了 Gli2 蛋白水平,而蛋白酶体抑制剂 MG-132 处理恢复了 Gli2 的表达。此外,OTUB2 的过表达稳定了 U2OS 细胞中的 Gli2 蛋白,并延长了 Gli2 的半衰期。我们还发现,OTUB2 的敲低减少了 Gli2 在体内的去泛素化。体外去泛素化实验表明,野生型 OTUB2 减少了泛素化的 Gli2,但 OTUB2 突变体则没有。我们还发现,OTUB2 的敲低抑制了 MSC 成骨过程中对 Shh 和 Smo 激动剂的响应中碱性磷酸酶(ALP)活性和常见标志物 BMP2 和 RUNX2 的表达,这表明 OTUB2 可能通过调节 Hh 信号对成骨分化有影响。