Study Rationale:
Our present understanding of LRRK2 is held back by a lack of structural information. Our
interdisciplinary team will solve structures of specific familial (inherited) mutants of LRRK2 that drive
Parkinson's disease (PD), and, in parallel, we will engineer mutants that mimic the
familial mutations. These mutants all lock LRRK2 into stable structural states that become
trapped on microtubules (cell structure supports). Using crystallography (study of crystal structure) and high-resolution cryo-electron microscopy (magnification of images under very cold temperatures; cryoEM), we will solve structures of purified mutants and will also characterize these same mutants in cells using cryo-electron tomography (magnification of structures under very cold temperatures; cryoET).
Hypothesis:
We hypothesize that familial mutations and our engineered mutants will trap stable
structural states of LRRK2 onto microtubules that will enable the characterization of the
protein both in purified form and in cells using a combination of crystallography and state-of-the
art high resolution techniques.
Study Design:
We will characterize familial LRRK2 mutants using mutagenesis (changes in genes), crystallography and
electron microscopy (EM). We will design mutations that mimic the familial mutations and that generate hyperactive forms of LRRK2, we will characterize and solve the structures of purified familial mutants using crystallography and cryoEM and we will explain lower-resolution structures of the proteins trapped onto microtubules in their cellular context. This work will be essential in understanding how different
structural dynamics affect their functional role.
Impact on Diagnosis/Treatment of Parkinson's Disease:
Our structures will lay the foundation for designing novel therapeutic agents that will target the
LRRK2 pathogenic mutants. They will also help determine the molecular basis for regulating
the structural states of LRRK2 and show how this regulation is disrupted in pathogenic
states.
Next Steps for Development:
Our goal is to determine the mechanisms that trap LRRK2 mutants into pathogenic states and to
provide structures for the research community to design novel types of inhibitors to intervene with this
pathogenesis.