Departamento de Bioquímica, UAM-CSIC, Facultad de Medicina UAM, 28029, Madrid, Spain.
Instituto de Investigaciones Biomédicas "Alberto Sols", UAM-CSIC, Facultad de Medicina UAM, 28029, Madrid, Spain.
Sci Rep. 2021 Apr 1;11(1):7320. doi: 10.1038/s41598-021-86847-2.
DJ-1/PARK7 mutations are linked with familial forms of early-onset Parkinson's disease (PD). We have studied the degradation of untagged DJ-1 wild type (WT) and missense mutants in mouse embryonic fibroblasts obtained from DJ-1-null mice, an approach closer to the situation in patients carrying homozygous mutations. The results showed that the mutants L10P, M26I, A107P, P158Δ, L166P, E163K, and L172Q are unstable proteins, while A39S, E64D, R98Q, A104T, D149A, A171S, K175E, and A179T are as stable as DJ-1 WT. Inhibition of proteasomal and autophagic-lysosomal pathways had little effect on their degradation. Immunofluorescence and biochemical fractionation studies indicated that M26I, A107P, P158Δ, L166P, E163K, and L172Q mutants associate with mitochondria. Silencing of mitochondrial matrix protease LonP1 produced a strong reduction of the degradation of the mitochondrial-associated DJ-1 mutants A107P, P158Δ, L166P, E163K, and L172Q but not of mutant L10P. These results demonstrated a mitochondrial pathway of degradation of those DJ-1 missense mutants implicated in PD pathogenesis.
DJ-1/PARK7 突变与早发性帕金森病（PD）的家族形式有关。我们研究了从 DJ-1 缺失型小鼠获得的鼠胚胎成纤维细胞中未标记 DJ-1 野生型（WT）和错义突变体的降解情况，这种方法更接近携带纯合突变的患者的情况。结果表明，突变体 L10P、M26I、A107P、P158Δ、L166P、E163K 和 L172Q 是不稳定的蛋白质，而 A39S、E64D、R98Q、A104T、D149A、A171S、K175E 和 A179T 与 DJ-1 WT 一样稳定。抑制蛋白酶体和自噬溶酶体途径对它们的降解几乎没有影响。免疫荧光和生化分级分离研究表明，M26I、A107P、P158Δ、L166P、E163K 和 L172Q 突变体与线粒体相关。线粒体基质蛋白酶 LonP1 的沉默导致与线粒体相关的 DJ-1 突变体 A107P、P158Δ、L166P、E163K 和 L172Q 的降解明显减少，但突变体 L10P 则没有。这些结果表明，那些与 PD 发病机制有关的 DJ-1 错义突变体存在一种线粒体降解途径。
