The Parkinson’s disease (PD)-associated kinase Leucine-Rich Repeat Kinase 2 (LRRK2) is a crucial modulator of the autophagy-lysosome pathway, but unclarity exists on the precise mechanics of its role and the direction of this modulation. In particular, LRRK2 is involved in the degradation of pathological alpha-synuclein, with pathogenic mutations precipitating neuropathology in cellular and animal models of PD, and a significant proportion of LRRK2 patients presenting Lewy neuropathology. Defects in autophagic processing and lysosomal degradation of alpha-synuclein have been postulated to underlie its accumulation and onset of neuropathology. Thus, it is critical to obtain a comprehensive knowledge on LRRK2-associated pathology. Here, we investigated a G2019S-LRRK2 recombinant cell line exhibiting accumulation of endogenous, phosphorylated alpha-synuclein. We found that G2019S-LRRK2 leads to accumulation of LC3 and abnormalities in lysosome morphology and proteolytic activity in a kinase-dependent fashion, but independent from constitutively active Rab10. Notably, LRRK2 inhibition was ineffective upon upstream blockade of autophagosome-lysosome fusion events, highlighting this step as critical for alpha-synuclein clearance.

帕金森病 (PD) 相关激酶富含亮氨酸重复激酶 2 (LRRK2) 是自噬-溶酶体途径的重要调节剂，但其作用的精确机制和这种调节的方向尚不清楚。特别是，LRRK2 参与病理性 α-突触核蛋白的降解，致病性突变可促进 PD 细胞和动物模型中的神经病理学，并且很大一部分 LRRK2 患者呈现路易神经病理学。α-突触核蛋白的自噬处理和溶酶体降解的缺陷被认为是其积累和神经病理学发作的基础。因此，获得 LRRK2 相关病理学的全面知识至关重要。在这里，我们研究了 G2019S-LRRK2 重组细胞系，该细胞系表现出内源性磷酸化 α-突触核蛋白的积累。我们发现 G2019S-LRRK2 以激酶依赖性方式导致 LC3 积累以及溶酶体形态和蛋白水解活性异常，但独立于组成型活性 Rab10。值得注意的是，LRRK2 抑制在上游阻断自噬体-溶酶体融合事件时无效，突出显示该步骤对于 α-突触核蛋白清除至关重要。