Small ubiquitin-like modifier-2 modification of retinoic acid receptor-alpha regulates its subcellular localization and transcriptional activity.
Small ubiquitin-like modifier-2 modification of retinoic acid receptor-alpha regulates its subcellular localization and transcriptional activity.
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DOI：
10.1210/en.2009-0868
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发表时间：
2009-12
期刊：
影响因子：
4.8
通讯作者：
Li Zhu;N. C. Santos;K. Kim
中科院分区：
文献类型：
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作者：
Li Zhu;N. C. Santos;K. Kim
维甲酸受体- α (Rara)基因对睾丸生殖细胞发育至关重要，不育的Rara敲除雄性小鼠证明了这一点。Rara编码蛋白（Rara）在支持细胞和生殖细胞中均有表达，但并不总是在细胞核中表达。以前，全反式维甲酸（ATRA）被证明可以增加支持细胞中RARA的核定位和转录活性。在这里，我们发现了一个小的泛素样修饰物-2 （SUMO-2）修饰作为一种新的翻译后调控机制，控制atra依赖的RARA亚细胞定位和转录。ATRA增加了对RARA的SUMO-2修改。当ATRA存在时，RARA的赖氨酸166 （K166）和K171在SUMO-2的生理浓度下被修饰，而当ATRA不存在时，K399是唯一被修饰的位点，但在较高的SUMO-2浓度下。然而，K399对atra控制的核ara贩运至关重要。在ATRA存在的情况下，K399对精氨酸的突变导致了K399R突变体的细胞质定位，这表明K166和K171的酰化对核定位有抑制作用。这可能是由于SUMO/sentrin特异性肽酶6 （SENP6）不能结合K399R突变体使支持细胞中的K166和K171脱氧，而它可以结合RARA和完整的K399。另一方面，当K399完整时，需要功能性的K166和K171位点进行sumo化才能获得完整的转录活性。这些结果共同表明，K166和K171的summoylation和去summoylation对优化RARA功能至关重要。
The retinoic acid receptor-alpha (Rara) gene is critical for germ cell development in the testis, as demonstrated by infertile Rara knockout male mice. The encoded protein for Rara (RARA) is expressed in both Sertoli cells and germ cells, but it is not always in the nucleus. Previously, all-trans retinoic acid (ATRA) was shown to increase the nuclear localization and transcriptional activity of RARA in Sertoli cells. Here, we identified a small ubiquitin-like modifier-2 (SUMO-2) modification as a novel posttranslational regulatory mechanism controlling the ATRA-dependent RARA subcellular localization and transcription. ATRA increased the SUMO-2 modification of RARA. In the presence of ATRA, lysine 166 (K166) and K171 of RARA were modified at a physiological concentration of SUMO-2, whereas in the absence of ATRA, K399 was the only site that was modified, but at a higher SUMO-2 concentration. However, K399 was critical for ATRA-controlled nuclear trafficking of RARA. In the presence of ATRA, a K399 mutation to arginine resulted in the cytoplasmic localization of K399R mutant, indicating that K166 and K171 sumoylations were inhibitory to nuclear localization. This may be due to SUMO/sentrin-specific peptidase 6 (SENP6) not being able to bind K399R mutant to desumoylate K166 and K171 in Sertoli cells, whereas it can bind RARA with intact K399. On the other hand, functional K166 and K171 sites for sumoylation were required for a full transcriptional activity, when K399 was intact. These results together suggest that both K166 and K171 sumoylation and desumoylation are critical for optimal RARA function.