title: LRRK2 secretion in exosomes is regulated by 14-3-3.
abstract: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause late-onset Parkinson's disease (PD). Emerging evidence suggests a role for LRRK2 in the endocytic pathway. Here, we show that LRRK2 is released in extracellular microvesicles (i.e. exosomes) from cells that natively express LRRK2. LRRK2 localizes to collecting duct epithelial cells in the kidney that actively secrete exosomes into urine. Purified urinary exosomes contain LRRK2 protein that is both dimerized and phosphorylated. We provide a quantitative proteomic profile of 1673 proteins in urinary exosomes and find that known LRRK2 interactors including 14-3-3 are some of the most abundant exosome proteins. Disruption of the 14-3-3 LRRK2 interaction with a 14-3-3 inhibitor or through acute LRRK2 kinase inhibition potently blocks LRRK2 release in exosomes, but familial mutations in LRRK2 had no effect on secretion. LRRK2 levels were overall comparable but highly variable in urinary exosomes derived from PD cases and age-matched controls, although very high LRRK2 levels were detected in some PD affected cases. We further characterized LRRK2 exosome release in neurons and macrophages in culture, and found that LRRK2-positive exosomes circulate in cerebral spinal fluid (CSF). Together, these results define a pathway for LRRK2 extracellular release, clarify one function of the LRRK2 14-3-3 interaction and provide a foundation for utilization of LRRK2 as a biomarker in clinical trials.
authors.affiliation: Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics.
authors.forename: Kyle B
authors.initials: KB
authors.lastname: Fraser
authors.forename: Mark S
authors.initials: MS
authors.lastname: Moehle
authors.forename: João P L
authors.initials: JP
authors.lastname: Daher
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Webber
authors.forename: Jeri Y
authors.initials: JY
authors.lastname: Williams
authors.forename: Carrie A
authors.initials: CA
authors.lastname: Stewart
authors.forename: Talene A
authors.initials: TA
authors.lastname: Yacoubian
authors.forename: Rita M
authors.initials: RM
authors.lastname: Cowell
authors.forename: Terje
authors.initials: T
authors.lastname: Dokland
authors.forename: Tong
authors.initials: T
authors.lastname: Ye
authors.forename: Dongquan
authors.initials: D
authors.lastname: Chen
authors.forename: Gene P
authors.initials: GP
authors.lastname: Siegal
authors.forename: Robert A
authors.initials: RA
authors.lastname: Galemmo
authors.forename: Elpida
authors.initials: E
authors.lastname: Tsika
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Moore
authors.forename: David G
authors.initials: DG
authors.lastname: Standaert
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kojima
authors.forename: James A
authors.initials: JA
authors.lastname: Mobley
authors.forename: Andrew B
authors.initials: AB
authors.lastname: West
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D000818:Animals; D004847:Epithelial Cells / Q000378:metabolism; D055354:Exosomes / Q000378:metabolism*; D006801:Humans; D007685:Kidney Tubules, Collecting / Q000378:metabolism; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; D008264:Macrophages / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D009154:Mutation; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D051381:Rats; D055647:Rats, Transgenic
chemical_list: D048948:14-3-3 Proteins; C495280:LRRK2 protein, human; C547428:LRRK2 protein, rat; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; C495279:Lrrk2 protein, mouse; D017346:Protein Serine-Threonine Kinases