Brassard Raelynn, Arutyunova Elena, Takyi Emmanuella, Espinoza-Fonseca L Michel, Young Howard S, Touret Nicolas, Lemieux M Joanne
Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta, Canada.
Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.
J Biol Chem. 2025 Mar;301(3):108253. doi: 10.1016/j.jbc.2025.108253. Epub 2025 Feb 3.
Parkinson's disease is a devastating neurodegenerative disease resulting from the death of dopaminergic neurons in the substantia nigra pars compacta of the midbrain. Familial and sporadic forms of the disease have been linked to mitochondrial dysfunction. Pathology has been identified with mutations in the PARK6 gene encoding PTEN-induced kinase 1 (PINK1), a quality control protein in the mitochondria. Disease-associated mutations at the transmembrane (TM) region of PINK1 protein were predicted to disrupt the cleavage of the TM region by the PARL (presenilin-associated rhomboid-like) protease at the inner mitochondrial membrane. Here, using microscopy, kinetic analysis, and molecular dynamics simulations, we analyzed three Parkinson's disease-associated TM mutations; PINK1-C92F, PINK1-R98W, and PINK1-I111S, and found that mitochondrial localization and cleavage by the PARL protease were not significantly impaired. However, clearance of hydrolyzed PINK1-R98W appears to be compromised because of altered positioning of the protein in the outer mitochondrial membrane, preventing association with translocase of the outer membrane complexes and slowing cleavage by PARL. This single amino acid change slows degradation of proteolyzed PINK1, increasing its accumulation at the outer mitochondrial membrane and resulting in increased mitophagy and decreased mitochondrial content among these cells.
帕金森病是一种毁灭性的神经退行性疾病，由中脑黑质致密部多巴胺能神经元死亡所致。该疾病的家族性和散发性形式均与线粒体功能障碍有关。已发现其病理学与编码PTEN诱导激酶1（PINK1）的PARK6基因突变有关，PINK1是线粒体中的一种质量控制蛋白。预测PINK1蛋白跨膜（TM）区域的疾病相关突变会破坏线粒体内膜上PARL（早老素相关类菱形蛋白酶）对TM区域的切割。在此，我们使用显微镜、动力学分析和分子动力学模拟，分析了三种与帕金森病相关的TM突变；PINK1-C92F、PINK1-R98W和PINK1-I111S，发现线粒体定位和PARL蛋白酶的切割并未受到显著损害。然而，由于PINK1-R98W蛋白在线粒体外膜中的定位改变，其水解产物的清除似乎受到了影响，这阻止了它与外膜转位酶复合物的结合，并减缓了PARL的切割。这一单氨基酸变化减缓了蛋白酶解的PINK1的降解，增加了其在线粒体外膜的积累，导致这些细胞中的线粒体自噬增加和线粒体含量减少。
