Biology subjects

Suenaga, S.

Publications and source records attributed to Suenaga, S..

4 recordsLinked to original sources

bioRxiv2026

STING activation drives pericentrosomal positioning of acidic organelles via the VAIL-LRRK2-Rab35 pathway

The cGAS-STING pathway is an innate immune system that responds to cytoplasmic double-stranded DNA, but recent studies have highlighted its noncanonical role in facilitating lysosomal stress responses. Specifically, STING activation has been shown to trigger V-ATPase-ATG16L1-induced LC3 lipidation (VAIL) and to activate LRRK2, a Parkinson disease-associated kinase, but the detailed molecular mechanism and the physiological roles of the activation have remained unclear. Here, we found that STING activation in microglia induces the translocation of LRRK2 to the pericentrosomal area, where lysosomes and recycling endosomes (REs) concentrate. This process was VAIL-dependent, and LRRK2 was found to be localized to the organelles. The translocation of LRRK2 required intact microtubule structures and was mediated by LRRK2 kinase activity, its substrate Rab35 and the motor adaptor proteins including JIP4. All these proteins were concentrated at the pericentrosomal area upon STING stimulation. The hyperactivating G2019S mutation of LRRK2 promoted the pericentrosomal translocation of these proteins. Overall, we propose a novel STING-induced noncanonical pathway that involves LRRK2 to facilitate pericentrosomal organelle positioning.

cell biology↗

bioRxiv2026

Subtype-specific secretion of extracellular vesicles by LRRK2 and Rab GTPases under lysosomal stress

LRRK2, the Parkinsons disease-associated kinase, phosphorylates a subset of Rab GTPases and regulates membrane dynamics. We previously reported that lysosomal stress activates LRRK2 and thereby induces the exocytic secretion of lysosomal contents, but the detailed secretion mechanism remained unclear. Here we found that, under lysosomal stress, endolysosomal luminal and membrane components were secreted with extracellular vesicles (EVs) via LRRK2. Bis(monoacylglycerol)phosphate, an endolysosomal lipid and a urinary marker of LRRK2 activity, was similarly secreted via LRRK2, whereas CD9-positive EVs were not involved. Further dissection of the secreted EVs revealed that Alix-positive EVs were secreted via Rab8a as well as the ESCRT component VPS4, whereas LAMP1/cathepsin B-positive EVs were secreted via Rab10/Rab35, and SNARE proteins syntaxin 2 and VAMP8 regulated the secretion of both EV subtypes. These findings suggest a distinctive stress-induced secretory mechanism whereby LRRK2 facilitates the secretion of multiple EV subtypes by controlling Rab GTPases involved in each pathway.

cell biology↗

bioRxiv2025

LRRK2 is activated by phosphatidylinositol 3-phosphate in conjunction with CASM

LRRK2 is a Parkinsons disease (PD)-associated kinase that phosphorylates Rab GTPases. Hyperactivation of LRRK2, which is thought to cause PD, occurs on stressed endolysosomal membranes via CASM (conjugation of ATG8 to single membranes) and Rab, whereas the involvement of specific membrane lipids remained unclear. Here, we found that LRRK2 was potently activated upon treatment with PIKfyve inhibitors that increase cellular phosphatidylinositol 3-phosphate (PI3P) levels, and that additional treatment with the class III phosphoinositide 3-kinase (PI3K) inhibitors blocking PI3P generation suppressed LRRK2 activation. Cellular PI3P levels were indeed correlated with the LRRK2 kinase activity. CASM-induced LRRK2 activation, but not CASM itself, was suppressed by PI3K inhibitors, whereas inhibition of CASM or Rab12/Rab29 suppressed LRRK2 activation induced by PIKfyve inhibitors. LRRK2 and phospho-Rab10 were co-localized with PI3P on LAMP1-positive enlarged vacuoles, and LRRK2 directly bound PI3P in vitro via its N-terminal positively charged amino acids. Together, we propose an updated mechanism of LRRK2 activation that requires CASM, Rab and PI3P-rich membranes.

cell biology↗

bioRxiv2021

Actively growing cells are the predominant persisters in exponential phase of Escherichia coli

Bacterial persistence is a phenomenon in which a small fraction of isogenic bacterial cells survives a lethal dose of antibiotics. Although the refractoriness of persistent cell populations has classically been attributed to growth-inactive cells generated before drug exposure, evidence is accumulating that actively growing cell fractions can also generate persister cells. However, single-cell characterization of persister cell history remains limited due to the extremely low frequencies of persisters. Here, we visualize the responses of over one million individual cells of wildtype Escherichia coli to lethal doses of antibiotics, sampling cells from different growth phases and culture media into a microfluidic device. We show that when cells sampled from exponentially growing populations were treated with ampicillin or ciprofloxacin, most persisters were growing before antibiotic treatment. Growing persisters exhibited heterogeneous survival dynamics, including continuous growth and fission with L-form-like morphologies, responsive growth arrest, or post-exposure filamentation. Incubating cells under stationary phase conditions increased both the frequency and the probability of survival of non-growing cells to ampicillin. Under ciprofloxacin, however, all persisters identified were growing before the antibiotic treatment, including samples from post-stationary phase culture. These results reveal diverse persister cell dynamics that depend on antibiotic types and pre-exposure history.

microbiology↗