Mid51/Fis1 mitochondrial oligomerization complex drives lysosomal untethering and network dynamics

作者：Yvette C. Wong, Soojin Kim, Jasmine Cisneros, Catherine G. Molakal, Pingping Song, Steven Lubbe, Dimitri Krainc · 发表于：The Journal of Cell Biology · 年份：2022 · DOI：10.1083/jcb.202206140 · 被引用次数：29 · 研究领域：Mitochondrial Function and Pathology、Autophagy in Disease and Therapy、Lysosomal Storage Disorders Research

Lysosomes are highly dynamic organelles implicated in multiple diseases. Using live super-resolution microscopy, we found that lysosomal tethering events rarely undergo lysosomal fusion, but rather untether over time to reorganize the lysosomal network. Inter-lysosomal untethering events are driven by a mitochondrial Mid51/Fis1 complex that undergoes coupled oligomerization on the outer mitochondrial membrane. Importantly, Fis1 oligomerization mediates TBC1D15 (Rab7-GAP) mitochondrial recruitment to drive inter-lysosomal untethering via Rab7 GTP hydrolysis. Moreover, inhibiting Fis1 oligomerization by either mutant Fis1 or a Mid51 oligomerization mutant potentially associated with Parkinson's disease prevents lysosomal untethering events, resulting in misregulated lysosomal network dynamics. In contrast, dominant optic atrophy-linked mutant Mid51, which does not inhibit Mid51/Fis1 coupled oligomerization, does not disrupt downstream lysosomal dynamics. As Fis1 conversely also regulates Mid51 oligomerization, our work further highlights an oligomeric Mid51/Fis1 mitochondrial complex that mechanistically couples together both Drp1 and Rab7 GTP hydrolysis machinery at mitochondria-lysosome contact sites. These findings have significant implications for organelle networks in cellular homeostasis and human disease.