The metabolic and signaling functions of lysosomes depend on their intracellular positioning and trafficking, but the underlying mechanisms are little understood. Here, we have discovered a novel septin GTPase–based mechanism for retrograde lysosome transport. We found that septin 9 (SEPT9) associates with lysosomes, promoting the perinuclear localization of lysosomes in a Rab7-independent manner. SEPT9 targeting to mitochondria and peroxisomes is sufficient to recruit dynein and cause perinuclear clustering. We show that SEPT9 interacts with both dynein and dynactin through its GTPase domain and N-terminal extension, respectively. Strikingly, SEPT9 associates preferentially with the dynein intermediate chain (DIC) in its GDP-bound state, which favors dimerization and assembly into septin multimers. In response to oxidative cell stress induced by arsenite, SEPT9 localization to lysosomes is enhanced, promoting the perinuclear clustering of lysosomes. We posit that septins function as GDP-activated scaffolds for the cooperative assembly of dynein–dynactin, providing an alternative mechanism of retrograde lysosome transport at steady state and during cellular adaptation to stress.
A septin GTPase scaffold of dynein–dynactin motors triggers retrograde lysosome transport
- Views Icon Views
- Share Icon Share
- Search Site
Ilona A. Kesisova, Benjamin P. Robinson, Elias T. Spiliotis; A septin GTPase scaffold of dynein–dynactin motors triggers retrograde lysosome transport. J Cell Biol 1 February 2021; 220 (2): e202005219. doi: https://doi.org/10.1083/jcb.202005219
Download citation file: