Pathogenic LRRK2 compromises the subcellular distribution of lysosomes in a Rab12-RILPL1-dependent manner

Area of Science:

• Cell Biology
• Neuroscience
• Genetics

Background:

• Mutations in leucine-rich repeat kinase 2 (LRRK2) are a significant cause of familial Parkinson's disease (PD).
• LRRK2 is known to phosphorylate Rab family proteins, including Rab12, with pathogenic mutations accelerating this process.

Purpose of the Study:

• To investigate the functional consequences of LRRK2 overexpression on organelle distribution in cultured cells.
• To elucidate the role of Rab12 phosphorylation in LRRK2-associated cellular dysfunction relevant to Parkinson's disease.

Main Methods:

• Overexpression of wild-type and mutant LRRK2 in cultured cells.
• Analysis of lysosomal distribution and organelle clustering.
• Gene knockout studies targeting RAB12 and RILPL1.
• Site-directed mutagenesis to investigate Rab12 phosphorylation at Ser106.

Main Results:

• Overexpression of pathogenic mutant LRRK2 caused perinuclear clustering of lysosomes, dependent on LRRK2 kinase activity.
• Lysosomal clustering was abrogated by knocking out RAB12 or its effector RILPL1.
• Phosphorylation of Rab12 at Ser106 was essential for lysosomal perinuclear clustering.
• Phosphorylated Rab12 accumulated on clustered lysosomes, and its phosphorylation enhanced interaction with RILPL1, disrupting lysosomal transport.

Conclusions:

• Increased Rab12 phosphorylation by pathogenic LRRK2 impairs intracellular lysosomal transport through enhanced Rab12-RILPL1 interaction.
• Abnormal lysosomal transport regulation is implicated in LRRK2-mediated Parkinson's disease pathogenesis.
• These findings offer new insights into the molecular mechanisms underlying familial Parkinson's disease.