Biology subjects

Yoshii, G.

Publications and source records attributed to Yoshii, G..

3 recordsLinked to original sources

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↗

bioRxiv2023

The V-ATPase-ATG16L1 axis recruits LRRK2 to facilitate lysosomal stress responses

Leucine-rich repeat kinase 2 (LRRK2), a Rab kinase associated with Parkinsons disease and several inflammatory diseases, has been shown to localize to stressed lysosomes and get activated to regulate lysosomal homeostasis. However, the mechanisms of LRRK2 recruitment and activation have not been well understood. Here we found that the ATG8 conjugation system regulates the recruitment of LRRK2 as well as LC3 onto single membranes of stressed lysosomes/phagosomes. This recruitment did not require FIP200-containing autophagy initiation complex, nor did it occur on double-membrane autophagosomes, suggesting independence from canonical autophagy. Consistently, LRRK2 recruitment was regulated by the V-ATPase-ATG16L1 axis, which requires the WD40 domain of ATG16L1 and specifically mediates ATG8 lipidation on single membranes. This mechanism was also responsible for the lysosomal stress-induced activation of LRRK2 and the resultant regulation of lysosomal secretion and enlargement. These results indicate that the V-ATPase-ATG16L1 axis serves a novel non-autophagic role in the maintenance of lysosomal homeostasis by recruiting LRRK2.

molecular biology↗

bioRxiv2020

Roles of lysosomotropic agents on LRRK2 activation and Rab10 phosphorylation

Leucine-rich repeat kinase 2 (LRRK2), the major causative gene product of autosomal-dominant Parkinsons disease, is a protein kinase that phosphorylates a subset of Rab GTPases. Since pathogenic LRRK2 mutations increase its ability to phosphorylate Rab GTPases, elucidating the mechanisms of how Rab phosphorylation is regulated by LRRK2 is of great importance. We have previously reported that chloroquine-induced lysosomal stress facilitates LRRK2 phosphorylation of Rab10 to maintain lysosomal homeostasis. Here we reveal that Rab10 phosphorylation by LRRK2 is potently stimulated by treatment of cells with a set of lysosome stressors and clinically used lysosomotropic drugs. These agents commonly promoted the formation of LRRK2-coated enlarged lysosomes and extracellular release of lysosomal enzyme cathepsin B, the latter being dependent on LRRK2 kinase activity. In contrast to the increase in Rab10 phosphorylation, treatment with lysosomotropic drugs did not increase the enzymatic activity of LRRK2, as monitored by its autophosphorylation at Ser1292 residue, but rather enhanced the molecular proximity between LRRK2 and its substrate Rab GTPases on the cytosolic surface of lysosomes. Lysosomotropic drug-induced upregulation of Rab10 phosphorylation was likely a downstream event of Rab29 (Rab7L1)-mediated enzymatic activation of LRRK2. These results suggest a regulated process of Rab10 phosphorylation by LRRK2 that is associated with lysosomal overload stress, and provide insights into the novel strategies to halt the aberrant upregulation of LRRK2 kinase activity.

molecular biology↗