ABSTRACT
Leucine-rich repeat kinase 2 (LRRK2) is the most commonly mutated gene in familial Parkinson's disease1 and is also linked to its idiopathic form2. LRRK2 has been proposed to function in membrane trafficking3 and colocalizes with microtubules4. Despite the fundamental importance of LRRK2 for understanding and treating Parkinson's disease, structural information on the enzyme is limited. Here we report the structure of the catalytic half of LRRK2, and an atomic model of microtubule-associated LRRK2 built using a reported cryo-electron tomography in situ structure5. We propose that the conformation of the LRRK2 kinase domain regulates its interactions with microtubules, with a closed conformation favouring oligomerization on microtubules. We show that the catalytic half of LRRK2 is sufficient for filament formation and blocks the motility of the microtubule-based motors kinesin 1 and cytoplasmic dynein 1 in vitro. Kinase inhibitors that stabilize an open conformation relieve this interference and reduce the formation of LRRK2 filaments in cells, whereas inhibitors that stabilize a closed conformation do not. Our findings suggest that LRRK2 can act as a roadblock for microtubule-based motors and have implications for the design of therapeutic LRRK2 kinase inhibitors.
Subject(s)
Cryoelectron Microscopy , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/chemistry , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Microtubules/chemistry , Microtubules/metabolism , Parkinson Disease/metabolism , Benzamides/pharmacology , Biocatalysis/drug effects , Dimerization , Dyneins/antagonists & inhibitors , Dyneins/metabolism , Humans , Kinesins/antagonists & inhibitors , Kinesins/metabolism , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/antagonists & inhibitors , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/ultrastructure , Microtubules/ultrastructure , Models, Molecular , Movement/drug effects , Protein Binding , Protein Domains/drug effects , Pyrazoles/pharmacology , WD40 RepeatsABSTRACT
Oscillatory mode coupling between two coherent laser beams is produced when an interference pattern moves against a quasi-static electrically strobed grating in a photorefractive AlGaAs/GaAs multiple-quantum-well diode operated in the quantum-confined Stark geometry. The oscillation frequency is equal to the frequency difference between the two laser beams and provides a method to measure high-frequency Doppler shifts or large surface displacements for laser-based ultrasound. Combined photorefractive gains (normally forbidden by symmetry in the Stark geometry) and absorptive gains approach 1200cm(-1)during two-wave mixing using moving gratings.
ABSTRACT
The temporal dynamics of photorefractive and absorptive gains during two-wave mixing in Stark geometry photorefractive quantum wells are investigated using moving gratings to break the symmetry of the photorefractive diodes to achieve nonreciprocal energy transfer between two coherent laser beams.
ABSTRACT
We present what is to our knowledge the first demonstration of photorefractive AlGaAs/GaAs quantum wells operated in the reflection geometry, using the quantum-confined Stark effect. This photorefractive geometry relies on volume reflection gratings of a small number of periods written in a nonstoichiometric multiple-quantum-well layer with counterpropagating beams. Combined absorptive and photorefractive twowave mixing gains as large as 1500 cm(-1) are observed under reverse bias of the diode.