Objective/Rationale:
Mutations in the leucine-rich repeat kinase 2 (LRRK2) are the most common known cause of PD. A major gap in our understanding of how LRRK2 causes PD is the lack of knowledge of LRRK2 physiological substrate(s). Thus, we propose to identify LRRK2 substrate(s) using a newly developed Protein Microarray technology with human proteins.
Project Description:
Increasing evidence suggests that LRRK2 is an upstream kinase in the signaling cascade that phosphorylates the downstream effectors (substrates). Thus, we will indentify LRRK2 substrate(s) by using a home-made high-throughput proteome chip with 4200 human proteins purified from a yeast expression system. We will then confirm the positive hits by various cell biology and biochemistry approaches.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
Identification of LRRK2 substrates will facilitate understanding of the molecular pathogenesis of LRRK2-related PD, provide potential innovative therapeutic targets, and help to develop the specific LRRK2 kinase assay and to screen for LRRK2 inhibitors to treat PD in future.
Anticipated Outcome:
We anticipate that we will indentify LRRK2 substrate(s) from protein arrays and post confirmation experiments. If we identify a real substrate, it will lead to a series interesting projects for future studies: exploring the role of this substrate in PD pathogenesis and developing rational therape
Final Outcome
Dr. Smith identified five possible candidate hits for LRRK2 substrates using a protein array. One protein in particular, a kinase, was shown to interact with G2019S-LRRK2 and to be primarily expressed within the cytoplasm. Dr. Smith is working to further validate this candidate protein.