SUMO-1 modification of PIASy, an E3 ligase, is necessary for PIASy-dependent activation of Tcf-4
SUMO-1 modification of PIASy, an E3 ligase, is necessary for PIASy-dependent activation of Tcf-4
复制标题
DOI：
10.1128/mcb.25.9.3506-3518.2005
复制
发表时间：
2005-05-01
影响因子：
5.3
通讯作者：
Kikuchi, A
中科院分区：
文献类型：
--
作者：
Ihara, M;Yamamoto, H;Kikuchi, A
我们以前已经表明，修饰Tcf-4，转录因子在Writ途径，与SUMO通过PIASy，SUMO E3连接酶，增强其转录活性。由于PIASy本身也被SUMO-1修饰，我们研究了PIASy的SUMO化在Tcf-4调节中的作用。发现Lys（35）是PIASy的SUMO化位点。其中Lys（35）突变为Arg的PIASy（K35 R）不增强Tcf-4的类小泛素化，尽管该PIASy突变体不丧失对其它蛋白质类小泛素化的连接酶活性。野生型PIASy和PIASyK 35 R在细胞核中显示出不同的分布，尽管两者都与Tef-4共定位。早幼粒细胞白血病蛋白，这是参与转录调控，与PIASy（K35 R）更频繁地比野生型PIASy在细胞核中。PIASy（K35 R）不能刺激Tcf-4的转录活性，而SUMO-1与PIASy（K35 R）的氨基末端结合既不能增强Tcf-4的SUMO化，也不能刺激Tcf-4的转录活性。这些结果表明，PIASy中Lys（35）的小泛素化决定了PIASy的核定位，并且它对于PIASy依赖的小泛素化和Tcf-4的转录激活是必需的。
We have previously shown that modification of Tcf-4, a transcription factor in the Writ pathway, with SUMO by PIASy, a SUMO E3 ligase, enhances its transcriptional activity. Since PIASy itself was also modified with SUMO-1, we studied the role of sumoylation of PIASy in the regulation of Tcf-4. Lys(35) was found to be a sumoylation site of PIASy. PIASy(K35R), in which Lys(35) was mutated to Arg, did not enhance sumoylation of Tcf-4, although this PIASy mutant did not lose the ligase activity of sumoylation for other proteins. Wild-type PIASy and PIASyK35R showed a distinct distribution in the nucleus, although both were colocallized with Tef-4. Promyelocytic leukemia protein, which is involved in transcriptional regulation, was associated with PIASy(K35R) more frequently than wild-type PIASy in the nucleus. PIASy(K35R) could not stimulate the transcriptional activity of Tcf-4 under the conditions in which wild-type PIASy enhanced it. Conjugation of SUMO-1 to the amino terminus of PIASy(K35R) neither enhanced sumoylation of Tcf-4 nor stimulated the transcriptional activity of Tcf-4. These results suggest that sumoylation of Lys(35) in PIASy determines the nuclear localization of PIASy and that it is necessary for PIASy-dependent sumoylation and transcriptional activation of Tcf-4.