Abstract：
Spautin-1 is a well-known macroautophagy/autophagy inhibitor via suppressing the deubiquitinases USP10 and USP13 and promoting the degradation of the PIK3C3/VPS34-BECN1 complex, while its effect on selective autophagy remains poorly understood. Mitophagy is a selective form of autophagy for removal of damaged and superfluous mitochondria via the autophagy-lysosome pathway. Here, we report a surprising discovery that, while spautin-1 remains as an effective autophagy inhibitor, it promotes PINK1-PRKN-dependent mitophagy induced by mitochondrial damage agents. Mechanistically, spautin-1 facilitates the stabilization and activation of the full-length PINK1 at the outer mitochondrial membrane (OMM) via binding to components of the TOMM complex (TOMM70 and TOMM20), leading to the disruption of the mitochondrial import of PINK1 and prevention of PARL-mediated PINK1 cleavage. Moreover, spautin-1 induces neuronal mitophagy in Caenorhabditis elegans (C. elegans) in a PINK-1-PDR-1-dependent manner. Functionally, spautin-1 is capable of improving associative learning capability in an Alzheimer disease (AD) C. elegans model. In summary, we report a novel function of spautin-1 in promoting mitophagy via the PINK1-PRKN pathway. As deficiency of mitophagy is closely implicated in the pathogenesis of neurodegenerative disorders, the pro-mitophagy function of spautin-1 might suggest its therapeutic potential in neurodegenerative disorders such as AD.Abbreviations: AD, Alzheimer disease; ATG, autophagy related; BafA1, bafilomycin A1; CALCOCO2/NDP52, calcium binding and coiled-coil domain 2; CCCP, carbonyl cyanide m-chlorophenyl hydrazone; COX4/COX IV, cytochrome c oxidase subunit 4; EBSS, Earle\'s balanced salt; ECAR, extracellular acidification rate; GFP, green fluorescent protein; IA, isoamyl alcohol; IMM, inner mitochondrial membrane; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; MMP, mitochondrial membrane potential; mtDNA, mitochondrial DNA; nDNA, nuclear DNA; O/A, oligomycin-antimycin; OCR, oxygen consumption rate; OMM, outer mitochondrial membrane; OPTN, optineurin; PARL, presenilin associated rhomboid like; PINK1, PTEN induced kinase 1; PRKN, parkin RBR E3 ubiquitin protein ligase; p-Ser65-Ub, phosphorylation of Ub at Ser65; TIMM23, translocase of inner mitochondrial membrane 23; TOMM, translocase of outer mitochondrial membrane; USP10, ubiquitin specific peptidase 10; USP13, ubiquitin specific peptidase 13; VAL, valinomycin; YFP, yellow fluorescent protein.
摘要：
Spautin-1是一种众所周知的巨自噬/自噬抑制剂，通过抑制去泛素酶USP10和USP13并促进PIK3C3/VPS34-BECN1复合物的降解，而其对选择性自噬的影响仍知之甚少。线粒体自噬是一种选择性的自噬形式，通过自噬-溶酶体途径清除受损和多余的线粒体。这里,我们报告了一个令人惊讶的发现，虽然spautin-1仍然是一种有效的自噬抑制剂，它促进线粒体损伤剂诱导的PINK1-PRKN依赖性线粒体自噬。机械上,spauthin-1通过与TOMM复合物的成分（TOMM70和TOMM20）结合，促进线粒体外膜（OMM）上全长PINK1的稳定和激活，导致PINK1线粒体输入的破坏和PARL介导的PINK1裂解的预防。此外，spautin-1诱导秀丽隐杆线虫的神经元线粒体自噬（C.秀丽隐杆线虫）以依赖PINK-1-PDR-1的方式。功能上,spautin-1能够改善阿尔茨海默病(AD)C.elegans模型中的联想学习能力。总之,我们报道了spauthin-1通过PINK1-PRKN途径促进线粒体自噬的新功能。由于线粒体自噬的缺乏与神经退行性疾病的发病机制密切相关，spauthin-1的亲线粒体自噬功能可能提示其在AD等神经退行性疾病中的治疗潜力。
