Phosphorylation of serine 303 is a prerequisite for the stress-inducible SUMO modification of heat shock factor 1
Phosphorylation of serine 303 is a prerequisite for the stress-inducible SUMO modification of heat shock factor 1
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DOI：
10.1128/mcb.23.8.2953-2968.2003
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发表时间：
2003-04-01
影响因子：
5.3
通讯作者：
Sistonen, L
中科院分区：
文献类型：
--
作者：
Hietakangas, V;Ahlskog, JK;Sistonen, L
热休克反应伴随着热休克蛋白(HSPs)的快速而强劲的上调，是一种高度保守的保护机制，可抵御蛋白质损伤应激。热休克蛋白的诱导主要受应激诱导的热休克因子1(HSF1)在转录水平上的调节。一旦激活，HSF1就会三聚化，与DNA结合，集中在核应激颗粒中，并经历显著的多位点磷酸化，这与其转录活性有关。在这项研究中，我们证明了HSF1是以应力诱导的方式被SUMO-1和SUMO-2修饰的。位于HSF1调节域的赖氨酸298与几个关键的磷酸化位点相邻，其苏莫化作用迅速而短暂地增强。对HSF1磷酸化位点突变体的SUMO分析表明，在体内，缺乏磷酸化的S303突变体没有进行SUMO修饰，而模拟S303磷酸化的突变体在体外促进了HSF1的SUMO修饰，这表明K298的SUMO修饰需要S303的磷酸化。这一发现得到了磷酸多肽定位和S303/7磷酸特异性抗体分析的进一步支持，这表明丝氨酸303是强热诱导磷酸化的靶标，对应于可诱导的HSF1总甲基化。HSF1和SUMO-1在核应激颗粒中的瞬时磷酸化依赖的共定位为HSF1和SUMO之间严格调控的亚核相互作用提供了证据。
The heat shock response, which is accompanied by a rapid and robust upregulation of heat shock proteins (Hsps), is a highly conserved protection mechanism against protein-damaging stress. Hsp induction is mainly regulated at transcriptional level by stress-inducible heat shock factor 1 (HSF1). Upon activation, HSF1 trimerizes, binds to DNA, concentrates in the nuclear stress granules, and undergoes a marked multisite phosphorylation, which correlates with its transcriptional activity. In this study, we show that HSF1 is modified by SUMO-1 and SUMO-2 in a stress-inducible manner. Sumoylation is rapidly and transiently enhanced on lysine 298, located in the regulatory domain of HSF1, adjacent to several critical phosphorylation sites. Sumoylation analyses of HSF1 phosphorylation site mutants reveal that specifically the phosphorylation-deficient S303 mutant remains devoid of SUMO modification in vivo and the mutant mimicking phosphorylation of S303 promotes HSF1 sumoylation in vitro, indicating that S303 phospborylation is required for K298 sumoylation. This finding is further supported by phosphopeptide mapping and analysis with S303/7 phosphospecific antibodies, which demonstrate that serine 303 is a target for strong heat-inducible phosphorylation, corresponding to the inducible HSF1 sumoylation. A transient phosphorylation-dependent colocalization of HSF1 and SUMO-1 in nuclear stress granules provides evidence for a strictly regulated subnuclear interplay between HSF1 and SUMO.