Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
Cell Rep. 2023 Aug 29;42(8):112960. doi: 10.1016/j.celrep.2023.112960. Epub 2023 Aug 8.
The small ubiquitin-like modifier (SUMO) protease SENP6 disassembles SUMO chains from cellular substrate proteins. We use a proteomic method to identify putative SENP6 substrates based on increased apparent molecular weight after SENP6 depletion. Proteins of the lamin family of intermediate filaments show substantially increased SUMO modification after SENP6 depletion. This is accompanied by nuclear structural changes remarkably like those associated with laminopathies. Two SUMO attachment sites on lamin A/C are close to sites of mutations in Emery-Driefuss and limb girdle muscular dystrophy. To establish a direct link between lamin SUMOylation and the observed phenotype, we developed proximity-induced SUMO modification (PISM), which fuses a lamin A/C targeting DARPin to a SUMO E3 ligase domain. This directly targets lamin A/C for SUMO conjugation and demonstrates that enhanced lamin SUMO modification recapitulates the altered nuclear structure manifest after SENP6 depletion. This shows SENP6 activity protects the nucleus against hyperSUMOylation-induced laminopathy-like alterations.
小泛素样修饰物 (SUMO) 蛋白酶 SENP6 从细胞底物蛋白中解离 SUMO 链。我们使用蛋白质组学方法基于 SENP6 耗竭后表观分子量增加来鉴定潜在的 SENP6 底物。中间丝层粘连蛋白家族的蛋白质在 SENP6 耗竭后表现出明显增加的 SUMO 修饰。这伴随着核结构的显著变化，与 laminopathies 相关的变化非常相似。 lamin A/C 上的两个 SUMO 附着位点靠近 Emery-Driefuss 和肢体带肌营养不良症中的突变位点。为了在 lamin SUMOylation 和观察到的表型之间建立直接联系，我们开发了邻近诱导 SUMO 修饰 (PISM)，它将 lamin A/C 靶向 DARPin 融合到 SUMO E3 连接酶结构域中。这直接将 lamin A/C 靶向 SUMO 缀合，并证明增强的 lamin SUMO 修饰再现了 SENP6 耗竭后改变的核结构。这表明 SENP6 活性可保护核免受 hyperSUMOylation 诱导的 laminopathy 样改变。
