The structural basis for LRRK2's activation and autoinhibition

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• Mutations in Leucine-Rich Repeat Kinase 2 (LRRK2) are a significant cause of autosomal-dominant Parkinson's disease (PD).
• Elevated LRRK2 kinase activity is implicated in idiopathic PD, highlighting LRRK2 as a key therapeutic target.
• LRRK2 is a large enzyme comprising Ras-like GTPase (ROC) and kinase domains.

Purpose of the Study:

• To elucidate the regulatory mechanism of LRRK2.
• To understand how PD-associated mutations affect LRRK2 function.
• To identify potential therapeutic strategies targeting LRRK2 activity.

Main Methods:

• Cryo-electron microscopy (cryo-EM) for structural analysis.
• Biochemical reconstitution assays to study enzyme activity.
• Cell-based assays to validate findings in a biological context.

Main Results:

• The ROC GTPase domain controls LRRK2's switch between autoinhibited and active states.
• GTP binding promotes LRRK2 activation, whereas GDP binding induces autoinhibition.
• Common PD mutations (G2019S, R1441C/G/H) activate LRRK2 via distinct structural pathways, indicating genotype-specific dysregulation.

Conclusions:

• A unified framework for LRRK2 regulation is established, linking GTPase activity to kinase function.
• Stabilizing the GDP-bound state offers a potential inhibitory strategy for LRRK2 in PD.
• Modulating LRRK2 activity, particularly the GTP-bound state, may have context-specific benefits, such as in the lung.