RNF4可以促進AP-1反應單元的活性

RNF4 enhances AP-1 response element activity

劉靜穎(Ching-Yin Liu)

指導教授 ： 李玉梅

國立臺灣大學/生命科學院/生化科學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01633

摘要

RNF4是個分布在細胞核中，具有RING finger的蛋白質，目前已知可以與許多不同細胞核中的蛋白質作用，此外，能夠調控以類固醇受器為主的以及一些細胞中基礎的轉錄機制。另外，RNF4也被發現可以作為協同的抑制因子或是活化因子來影響轉錄機制的進行。在這次的研究中，我們發現了RNF4可以促進AP-1的轉錄活性。而且，藉由Luciferase assay的實驗中，我們發現在RNF4促進AP-1的轉錄活性過程中，c-Jun amino-terminal kinase (JNK) 以及extracellular signal-regulated kinases (ERK)這兩類的蛋白質都參與其中。除此之外，進一步的利用免疫沉澱的方式，我們也證明了RNF4能夠與活化狀態的磷酸化JNK及磷酸化的ERK有直接的作用。在截短的RNF4實驗中，我們也發現了RNF4失去了C端的RING finger區域對於RNF4促進AP-1的轉錄活性就會消失。而在RNF4上胺基酸序列第127的Threonine和第166的Serine這兩個磷酸化的位置，如果被突變成Alanine之後也會失去部分活化AP-1的能力。

關鍵字

ERK ； JNK ； RNF4 ； AP-1

並列摘要

The small nuclear RING finger protein 4 (RNF4) contain C3HC4-type RING motif in the c-terminal region. RNF4 modulates both steroid-receptor-dependent and basal transcription and interacts with a variety of nuclear proteins. RNF4 can also act as a transcriptional co-repressor or co-activator. In this study, we demonstrated that RNF4 enhance AP-1 (activating protein-1) transcriptional activity. Using luciferase assay, we showed that RNF4 regulates AP-1 through c-Jun amino-terminal kinase (JNK) and extracellular signal-regulated kinases (ERK) pathway. In addition, GST-pull down assay indicated that RNF4 can interact with p-JNK and p-ERK. When RING finger motif is deleted, RNF4 loses its ability to enhance AP-1 activity. T127, S166 phosphorylation sites of RNF4 is critical to activate AP-1 transcription. If the two phosphorylation sites mutated to Alanine, RNF4 lose the enhancement of AP-1 activity. Based on these results, we propose that RNF4 enhance AP-1 transcription activity.

並列關鍵字

JNK ； RNF4 ； ERK ； AP-1

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