Missense mutations along the leucine-rich repeat kinase
2 (LRRK2)
protein are a major contributor to Parkinson’s Disease (PD),
the second most commonly occurring neurodegenerative disorder worldwide.
We recently reported the development of allosteric constrained peptide
inhibitors that target and downregulate LRRK2 activity through disruption
of LRRK2 dimerization. In this study, we designed doubly constrained
peptides with the objective of inhibiting C-terminal of Roc (COR)–COR
mediated dimerization at the LRRK2 dimer interface. We show that the
doubly constrained peptides are cell-permeant, bind wild-type and
pathogenic LRRK2, inhibit LRRK2 dimerization and kinase activity,
and inhibit LRRK2-mediated neuronal apoptosis, and in contrast to
ATP-competitive LRRK2 kinase inhibitors, they do not induce the mislocalization
of LRRK2 to skein-like structures in cells. This work highlights the
significance of COR-mediated dimerization in LRRK2 activity while
also highlighting the use of doubly constrained peptides to stabilize
discrete secondary structural folds within a peptide sequence.