Identification of peptides interfering with the LRRK2/PP1 interaction

Area of Science:

• Biochemistry
• Neuroscience
• Molecular Biology

Background:

• Serine/threonine phosphatases regulate protein kinase activity, influencing various pathologies.
• Leucine-Rich Repeat Kinase 2 (LRRK2) is a protein associated with Parkinson's disease.
• The interaction between LRRK2 and Protein Phosphatase 1 (PP1) is a potential target for therapeutic intervention.

Purpose of the Study:

• To identify and characterize peptides that can disrupt the LRRK2/PP1 interaction.
• To develop cell-penetrating and blood-brain barrier-penetrating peptides for studying LRRK2/PP1 in pathological conditions.
• To create novel tools for investigating the role of LRRK2/PP1 interaction in normal and disease states.

Main Methods:

• PEP-scan approach to identify LRRK2 peptides interacting with PP1.
• Synthesis of interfering peptides and fusion with cell-penetrating peptides.
• FITC-labeling for cellular internalization studies and ELISA for protein association confirmation.
• Fusion with blood-brain barrier shuttle peptides and protease degradation assays.

Main Results:

• Identified two peptides (Mut3DPT-LRRK2-Short and Mut3DPT-LRRK2-Long) that disrupt LRRK2/PP1 interaction.
• Confirmed peptide internalization into cell lines and primary human cells.
• Demonstrated association of Mut3DPT-LRRK2-Long with purified PP1.
• Developed protease-resistant, blood-brain barrier-penetrating peptides (BBB-LRRK2-Short and BBB-LRRK2-Long) that block LRRK2/PP1 interaction and enter cells.

Conclusions:

• Novel interfering peptides effectively disrupt the LRRK2/PP1 interaction.
• Cell-penetrating and blood-brain barrier-penetrating versions of these peptides have been successfully developed.
• These peptides serve as valuable new tools for exploring the LRRK2/PP1 interaction in Parkinson's disease and other related conditions.