Min Wang Ki, Kwak Jun Soo, Kwon Dae Hwan, Kim Sung-Il, Park Sang Woo, Ahn Jiyoung, Cho Soobin, Kim Myung-Jin, Lee Seung Ju, Song Jong Tae, Kim Yonghwan, Seo Hak Soo
Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Korea.
Department of Biological Sciences, Research Institute of Women's Health and Digital Humanity Center, Sookmyung Women's University, Seoul, 04310, Korea.
Plant J. 2025 Apr;122(2):e70166. doi: 10.1111/tpj.70166.
Vacuolar protein sorting 29 (VPS29) functions in retrograde protein transport as a component of the retromer complex. However, the role of VPS29 in the regulation of post-translational modifications, such as sumoylation and ubiquitination, has not been elucidated. In this study, we demonstrate that VPS29 positively regulates SIZ/PIAS-type E3 SUMO (Small ubiquitin-related modifier) ligase-mediated sumoylation systems. In Arabidopsis, vps29-3 mutants display upregulated salicylic acid (SA) signaling pathways and reactive oxygen species accumulation, similar to those observed in siz1 mutants. Arabidopsis VPS29 (AtVPS29) directly interacts with the Arabidopsis E3 SUMO ligase SIZ1 (AtSIZ1) and localizes not only to the cytoplasm but also to the nucleus. The loss of AtVPS29 leads to a depletion of AtSIZ1, whereas the E3 ubiquitin ligase constitutive photomorphogenic 1 (COP1), an upstream regulator of AtSIZ1, accumulates in vps29-3 mutants. Conversely, overexpression of AtVPS29 results in the accumulation of AtSIZ1 and the depletion of COP1 in transgenic Arabidopsis. Similarly, in human cells, silencing of hVPS29 leads to the depletion of the E3 SUMO ligase, PIAS1, and the accumulation of huCOP1. Under heat stress conditions, the levels of SUMO-conjugates are significantly lower in Arabidopsis vps29-3 mutants, indicating a regulatory role of AtVPS29 on AtSIZ1 activity. Moreover, AtVPS29 inhibits ubiquitination pathway-dependent degradation of AtSIZ1. Notably, AtSIZ1 forms a complex with AtVPS29 and trimeric retromer proteins. Taken together, our results indicate that VPS29 plays an essential role in signal transduction by regulating SIZ/PIAS-type E3 ligase-dependent sumoylation in both plants and animals.
液泡蛋白分选29（VPS29）作为逆向转运蛋白复合物的一个组成部分，在逆向蛋白运输中发挥作用。然而，VPS29在翻译后修饰调控中的作用，如SUMO化和泛素化，尚未阐明。在本研究中，我们证明VPS29正向调控SIZ/PIAS型E3 SUMO（小泛素相关修饰物）连接酶介导的SUMO化系统。在拟南芥中，vps29 - 3突变体表现出上调的水杨酸（SA）信号通路和活性氧积累，类似于在siz1突变体中观察到的情况。拟南芥VPS29（AtVPS29）直接与拟南芥E3 SUMO连接酶SIZ1（AtSIZ1）相互作用，不仅定位于细胞质，还定位于细胞核。AtVPS29的缺失导致AtSIZ1的减少，而E3泛素连接酶组成型光形态建成1（COP1），即AtSIZ1的上游调节因子，在vps29 - 3突变体中积累。相反，AtVPS29的过表达导致转基因拟南芥中AtSIZ1的积累和COP1的减少。同样，在人类细胞中，hVPS29的沉默导致E3 SUMO连接酶PIAS1的减少和huCOP1的积累。在热胁迫条件下，拟南芥vps29 - 3突变体中SUMO缀合物的水平显著降低，表明AtVPS29对AtSIZ1活性具有调节作用。此外，AtVPS29抑制AtSIZ1的泛素化途径依赖性降解。值得注意的是，AtSIZ1与AtVPS29和三聚体逆向转运蛋白形成复合物。综上所述，我们的结果表明VPS29在植物和动物中通过调节SIZ/PIAS型E3连接酶依赖性SUMO化在信号转导中起重要作用。
