TRIM1 coexpression recruits LRRK2 to microtubules. Live-cell confocal microscopy of fluorescently tagged LRRK2 and tubulin, TRIM1, or TRIM18 constructs transiently transfected into H1299 cells. Insets in a–e show higher magnification of region identified by the yellow box. (a) In the presence of mCherry-tubulin, GFP-LRRK2 is diffusely cytoplasmic. From left to right: mCherry-tubulin, GFP-LRRK2, and merged image. (b) In the presence of mCherry-TRIM1, GFP-LRRK2 localizes to microtubules. From left to right: mCherry-TRIM1, GFP-LRRK2, and merged image. (c) In the presence of mCherry-TRIM18, GFP-LRRK2 is diffusely cytoplasmic. From left to right: mCherry-TRIM18, GFP-LRRK2, and merged image. (d) mCherry-TRIM1 C is cytoplasmic. When coexpressed with GFP-LRRK2, both remain diffusely cytoplasmic. From left to right: mCherry-TRIM1 C, GFP-LRRK2, and merged image. (e) GFP-TRIM1 ∆RF maintains microtubule localization and colocalizes with mCherry-LRRK2. From left to right: GFP-TRIM1 ∆RF, mCherry-LRRK2, and merged image. (f) Quantification of cells with microtubule-associated LRRK2 when coexpressed with indicated proteins in H1299 cells. 100 cells were evaluated in each condition in each of three independent experiments; bars show mean ± SD. Significance testing for f was performed using Kruskal–Wallis with post hoc Dunn test and Bonferroni correction. Scale bars = 10 µm.