title: Re-examination of the dimerization state of leucine-rich repeat kinase 2: predominance of the monomeric form.
abstract: Mutations in the LRRK2 (leucine-rich repeat kinase 2) gene have been identified in PARK8, a major form of autosomal-dominantly inherited familial Parkinson's disease, although the biochemical properties of LRRK2 are not fully understood. It has been proposed that LRRK2 predominantly exists as a homodimer on the basis of the observation that LRRK2, with a theoretical molecular mass of 280 kDa, migrates at 600 kDa (p600 LRRK2) on native polyacrylamide gels. In the present study, we biochemically re-examined the nature of p600 LRRK2 and found that p600 LRRK2 was fractionated with a single peak at ~272 kDa by ultracentrifugation on a glycerol gradient. In addition, p600 LRRK2 behaved similarly to monomeric proteins upon two-dimensional electrophoretic separation. These results suggested a monomeric composition of p600 LRRK2 within cells. The p600 LRRK2 exhibited kinase activity as well as GTP-binding activity, and forced dimerization of LRRK2 neither upregulated its kinase activity nor altered its subcellular localization. Collectively, we conclude that the monomer form of LRRK2 is predominant within cells, and that dimerization is dispensable for its enzymatic activity.
authors: Department of Neuropathology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-0033, Japan.
authors: Genta
authors: G
authors: Ito
authors: Takeshi
authors: T
authors: Iwatsubo
mesh_terms: D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D057809:HEK293 Cells; D006801:Humans; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; D051379:Mice; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D009994:Osmolar Concentration; D055503:Protein Multimerization / Q000187:drug effects / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis / Q000187:drug effects; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D041701:Swiss 3T3 Cells; D014162:Transfection
chemical_list: D046912:Multiprotein Complexes; D012967:Sodium Dodecyl Sulfate; C495280:LRRK2 protein, human; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; D017346:Protein Serine-Threonine Kinases