Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China.
Acta Pharmacol Sin. 2010 Oct;31(10):1293-302. doi: 10.1038/aps.2010.96. Epub 2010 Aug 16.
To elucidate how krüppel-like factor 4 (KLF4) activates mitofusin 2 (mfn-2) expression in all-trans retinoic acid (ATRA)-induced vascular smooth muscle cell (VSMC) differentiation.
The mfn-2 promoter-reporter constructs and the KLF4 acetylation-deficient or phosphorylation-deficient mutants were constructed. Adenoviral vector of KLF4-mediated overexpression and Western blot analysis were used to determine the effect of KLF4 on mfn-2 expression. The luciferase assay and chromatin immunoprecipitation were used to detect the transactivation of KLF4 on mfn-2 gene expression. Co-immunoprecipitation and GST pull-down assays were used to determine the modification of KLF4 and interaction of KLF4 with p300 in VSMCs.
KLF4 mediated ATRA-induced mfn-2 expression in VSMCs. KLF4 bound directly to the mfn-2 promoter and activated its transcription. ATRA increased the interaction of KLF4 with p300 by inducing KLF4 phosphorylation via activation of JNK and p38 MAPK signaling. KLF4 acetylation by p300 increased its activity to transactivate the mfn-2 promoter.
ATRA induces KLF4 acetylation by p300 and increases the ability of KLF4 to transactivate the mfn-2 promoter in VSMCs.
阐明 Krüppel 样因子 4（KLF4）如何激活全反式视黄酸（ATRA）诱导的血管平滑肌细胞（VSMC）分化中的线粒体融合蛋白 2（mfn-2）表达。
构建 mfn-2 启动子报告构建体和 KLF4 乙酰化缺陷或磷酸化缺陷突变体。使用 KLF4 介导的过表达腺病毒载体和 Western blot 分析来确定 KLF4 对 mfn-2 表达的影响。使用荧光素酶测定和染色质免疫沉淀来检测 KLF4 对 mfn-2 基因表达的转录激活。共免疫沉淀和 GST 下拉测定用于确定 KLF4 的修饰以及 KLF4 与 VSMCs 中 p300 的相互作用。
KLF4 介导 ATRA 诱导的 VSMCs 中的 mfn-2 表达。KLF4 直接结合到 mfn-2 启动子上并激活其转录。ATRA 通过激活 JNK 和 p38 MAPK 信号通路诱导 KLF4 磷酸化，从而增加 KLF4 与 p300 的相互作用。p300 对 KLF4 的乙酰化增加了其转录激活 mfn-2 启动子的活性。
ATRA 通过 p300 诱导 KLF4 乙酰化，并增加 KLF4 在 VSMCs 中转录激活 mfn-2 启动子的能力。
