Objective/Rationale:
Mutations in Leucine-Rich Repeat Kinase 2 (LRRK2) that increase the kinase’s activity – transferring groups of chemicals called phosphates – have been associated with neurodegeneration in Parkinson’s disease (PD). Despite the importance of LRRK2, current techniques for assessing LRRK2 activity changes in complex biological samples rely on indirect means. This proposal aims to develop a direct activity assay (laboratory procedure) capable of monitoring LRRK2 deviations in complex biological samples.
Project Description:
We propose the use of a phosphorylation-sensitive amino acid (a type of organic compound), which undergoes a dramatic increase in fluorescence in response to phosphorylation of an adjacent residue. We will also use, in combination, a LRRK2-selective peptide (sequence of amino acids) to afford a direct LRRK2 activity sensor. Our preliminary data demonstrates the ability to directly monitor LRRK2 activity using this proposed strategy. The studies outlined in this proposal focus on the further optimization of this assay for directly monitoring LRRK2 activity in complex biological samples.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
The proposed direct LRRK2 kinase activity assay will allow for the quantitative biochemical assessment of PD-associated LRRK2 mutations. Moreover, the availability of such an assay could enable the ability to monitor LRRK2 response to inhibitor treatment in PD models. Therefore this project could lead to an increased understanding of PD biochemistry as well as improved therapeutics for disease treatment.
Anticipated Outcome:
The completion of this project will enable the direct analysis of LRRK2 kinase activity in complex biological samples, without the need of indirect proxies. The availability of this assay will improve the biochemical understanding of PD as well as potentially lead to improved therapeutic strategies.