Cross-species divergence of the major recognition pathways of ubiquitylated substrates for ubiquitin/26S proteasome-mediated proteolysis
Cross-species divergence of the major recognition pathways of ubiquitylated substrates for ubiquitin/26S proteasome-mediated proteolysis
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DOI：
10.1111/j.1742-4658.2009.07531.x
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发表时间：
2010-02-01
期刊：
影响因子：
5.4
通讯作者：
Fu, Hongyong
中科院分区：
文献类型：
--
作者：
Fatimababy, Antony S.;Lin, Ya-Ling;Fu, Hongyong
泛素化底物的识别是泛素/26 S蛋白酶体介导的蛋白水解（UPP）的重要组成部分，UPP由蛋白酶体亚基RPN 10和/或RPN 13直接介导，或由含有泛素样结构域和泛素相关结构域的泛素受体间接介导。通过下拉和诱变试验，我们检测到跨物种的主要识别途径的分歧。RPN 10在拟南芥和酵母中的直接识别中起主要作用，这是基于对长链和K48连接的泛素链的强亲和力。相比之下，RPN 10和RPN 13同源物在人类中发挥主要作用。对于间接识别，RAD 23和DSK 2同源物（除了人DSK 2同源物）是主要受体。人RAD 23同源物通过RPN 10和RPN 13同源物靶向26 S蛋白酶体。相比之下，拟南芥分别使用RPN 10的UIM 1和UIM 3来结合DSK 2和RAD 23。酵母在RPN 10中使用UIM，在RPN 1中使用LRR。总体而言，多个蛋白酶体亚基负责直接和/或间接识别酵母和人类中的泛素化底物。相反，一个单一的蛋白酶体亚基，RPN 10，是关键的直接和间接识别途径在拟南芥。与这些结果一致，泛素化底物的积累和营养生长和生殖生长的严重多效性表型与拟南芥T-DNA插入突变体中RPN 10功能的丧失有关。这意味着所涉及的关键调节剂的靶向和蛋白水解受到影响。这些结果支持UPP的泛素化底物的主要识别途径的跨物种机制和功能分歧。
The recognition of ubiquitylated substrates is an essential element of ubiquitin /26S proteasome-mediated proteolysis (UPP), which is mediated directly by the proteasome subunit RPN10 and/or RPN13, or indirectly by ubiquitin receptors containing ubiquitin-like and ubiquitin-associated domains. By pull-down and mutagenesis assays, we detected cross-species divergence of the major recognition pathways. RPN10 plays a major role in direct recognition in Arabidopsis and yeast based on the strong affinity for the long and K48-linked ubiquitin chains. In contrast, both the RPN10 and RPN13 homologs play major roles in humans. For indirect recognition, the RAD23 and DSK2 homologs (except for the human DSK2 homolog) are major receptors. The human RAD23 homolog is targeted to the 26S proteasome by the RPN10 and RPN13 homologs. In comparison, Arabidopsis uses UIM1 and UIM3 of RPN10 to bind DSK2 and RAD23, respectively. Yeast uses UIM in RPN10 and LRR in RPN1. Overall, multiple proteasome subunits are responsible for the direct and/or indirect recognition of ubiquitylated substrates in yeast and humans. In contrast, a single proteasome subunit, RPN10, is critical for both the direct and indirect recognition pathways in Arabidopsis. In agreement with these results, the accumulation of ubiquitylated substrates and severe pleiotropic phenotypes of vegetative and reproductive growth are associated with the loss of RPN10 function in an Arabidopsis T-DNA insertion mutant. This implies that the targeting and proteolysis of the critical regulators involved are affected. These results support a cross-species mechanistic and functional divergence of the major recognition pathways for ubiquitylated substrates of UPP.