Identification of peptides interfering the lrrk2/pp1 interaction

ABSTRACT Serine/threonine phosphatases are responsible for counteracting the effect of the protein kinases implicated in the development of several pathologies. Here we identified by PEP-scan approach the sequence of a fragment of LRRK2, a Parkinson’s disease associated protein, interacting with the phosphatase PP1. The fragment, that is located in a LRRK2 domain of undefined function, was associated in N-terminal to an optimized cell penetrating peptide in order to study their in vitro and in vivo biological activity. From this original sequence, we developed and studied five interfering peptides (IPs) and identified two peptides able to disrupt the LRRK2/PP1 interaction by in vitro competition in anti-LRRK2 immunoprecipitates. Using FITC-labelled peptides, we confirmed the internalization of the peptides in cell lines as well as in and primary human normal and pathological cells. Finally, we have confirmed by ELISA test the association of Mut3DPT-LRRK2-Long and Mut3DPT-LRRK2-Short peptides to purified PP1 protein in a selective manner. The shortest peptides, MuteDPT-LRRK2-5 to 8 with either N or C-terminal deletions are not able neither disrupt the association LRRK2/PP1 nor to associate to purified PP1 protein. The peptides Mut3DPT-LRRK2-Long and Mut3DPT-LRRK2-Short may be new tools to study the role of LRRK2/PP1 interaction in normal and pathological conditions.