Objective/Rationale:
Our aim is the biochemical and structural characterization of the Roco family of proteins. Structures of different Roco constructs will give important insights in the molecular mechanism of LRRK2 activation, and how mutations of LRRK2 result in neuronal toxicity. In this way we hope to elucidate the function and mechanism of LRRK2 activation and thereby contribute to the understanding of the biochemical pathways responsible for LRRK2-linked PD and help to identify therapeutic targets for PD and related neurodegenerative disorders.
Project Description:
During the last several years, LRRK2 has been intensively studied. However all attempts to purify and determine the structure of full length LRRK2 and/or domains thereof have failed so far. Therefore, we propose to use related proteins, which can serve as models to understand the complex structure and regulatory mechanism of LRRK2. The project is divided into two parts: the first project will concentrate on the biochemical and structural characterization of the conserved RocCOR module of different bacterial Roco family proteins. The second part will focus on the elucidation of the structure and function of prototypes of LRRK2 in eukaryotes. Dictyostelium discoideum Roco proteins have similar domain architecture and very similar characteristics as LRRK2, but are biochemically and hopefully structurally more tractable
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
Our studies are intended to show how mutations spread over all parts of the multi-domain protein LRRK2 produces presumably a similar pathogenic output signal. We will construct the full complexity model for LRRK2 from structural analysis of the component parts using related domains from other organism. This should be crucial for identifying the target for interfering with pathogenic LRRK2. High resolution structure of the different domains would allow a high quality model of human LRRK2 protein to be built and used for computer-aided drug development.
Anticipated Outcome:
Structures of the different Roco construct will answer key questions for the intramolecular regulation of LRRK2 and give insight in the mechanism by which the Roc domain regulates kinase activity, how GTP binding and GTP activities of Roco proteins are regulated, the role that COR plays in this process and importantly how the PD-linked missense mutations alter the interactions between the different domains.