Autosomal dominant mutations in the leucine rich repeat kinase 2 (LRRK2) are the most common genetic cause of Parkinson's disease (PD). Despite the presence of multiple domains, the kinase activity of LRRK2 is thought to represent the primary function of the protein. Alterations in LRRK2 kinase activity are thought to underlie the pathogenesis of its PD-linked mutations; however, many questions regarding basic aspects of LRRK2 function remain unclear, including the cellular mechanisms of LRRK2 regulation and the importance of its unique distribution within the cell. Here, we demonstrate for the first time that the subcellular localization of wild-type LRRK2 is associated with changes in four distinct biochemical properties likely crucial for LRRK2 function. Our data demonstrate for the first time that the wild-type LRRK2 dimer possesses greater kinase activity than its more abundant monomeric counterpart. Importantly, we show that this activated form of LRRK2 is substantially enriched at the membrane of cells expressing endogenous or exogenous LRRK2, and that the membrane-associated fraction of LRRK2 likewise possesses greater kinase activity than cytosolic LRRK2. In addition, membraneassociated LRRK2 binds GTP more efficiently than cytosolic LRRK2, but demonstrates a lower degree of phosphorylation. Our observations suggest that multiple events, including altered protein-protein interactions and post-translational modification, contribute to the regulation of LRRK2 function, through modulating membrane association and complex assembly. These findings may have implications for the sites of LRRK2 function within the cell, the identification and localization of bona fide LRRK2 substrates, and efforts to design small molecule inhibitors of LRRK2.Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting 2% of population over the age of 50, with ~1.5 million patients in the US alone (1). Mutations in multiple genes are now known to cause familial PD (2,3), paving the way for molecular approaches to study the disease. The most common mutations in PD are found in the leucine rich repeat kinase 2 (LRRK2). They account for between 5% and 40% of familial parkinsonism and for 0.5-2.0% of sporadic PD cases (2,(4)(5)(6). The vast majority of cases with LRRK2 mutations present pathologically with α-synuclein inclusions, as in classic idiopathic PD (4,6), establishing the likelihood that studying LRRK2 may shed light 1 This work was supported by an Edward R. and Anne G. Lefler Postdoctoral Fellowship (ZB), NIH grant AG023094 (MJL) and the Brigham and Women's Hospital Udall Center of Excellence for Parkinson's Disease Research (NS038375).Correspondence should be addressed to MJL. (mlavoie@rics.bwh.harvard.edu), Phone: . SUPPORTING INFORMATION AVAILABLE Additional analyses of LRRK2 molecular weights, kinase activity, and GTP-binding can be found in the Supplementary Information. This material is available free of charge via the Internet at http://pubs.acs.org. NIH Public Access Author Manus...

We tested the relation between pain behavior, theta (4–8 Hz) oscillations in somatosensory cortex and burst firing in thalamic neurons in vivo. Optically-induced thalamic bursts attenuated cortical theta and mechanical allodynia. It is proposed that thalamic bursts are an adaptive response to pain that de-synchronizes cortical theta and decreases sensory salience.

We present a multimodal method combining quantitative electroencephalography (EEG), behavior and pharmacology for pre-clinical screening of analgesic efficacy in vivo. The method consists of an objective and non-invasive approach for realtime assessment of spontaneous nociceptive states based on EEG recordings of theta power over primary somatosensory cortex in awake rats. Three drugs were chosen: (1) pregabalin, a CNS-acting calcium channel inhibitor; (2) EMA 401, a PNS-acting angiotensin II type 2 receptor inhibitor; and (3) minocycline, a CNS-acting glial inhibitor. Optimal doses were determined based on pharmacokinetic studies and/or published data. The effects of these drugs at single or multiple doses were tested on the attenuation of theta power and paw withdrawal latency (PWL) in a rat model of neuropathic pain. We report mostly parallel trends in the reversal of theta power and PWL in response to administration of pregabalin and EMA 401, but not minocycline. We also note divergent trends at non-optimal doses and following prolonged drug administration, suggesting that EEG theta power can be used to detect false positive and false negative outcomes of the withdrawal reflex behavior, and yielding novel insights into the analgesic effects of these drugs on spontaneous nociceptive states in rats.