MTMR 2/3/4/7 KD disrupts the PM localization and nanoclustering of CTK. (A) MCF-7 cells stably co-expressing GFP-CTK (the C-terminal membrane anchor of KRAS without the G-domain) and shRNA targeting MTMR 2, 3, 4, or 7 were fixed with 4% PFA and imaged by confocal microscopy. (B) Intact basal PM sheets of cells from A were prepared, labeled with anti-GFP–conjugated gold particles, and visualized by EM. The graph shows a mean number of gold particles ± SEM (n ≥ 15). (C) Spatial mapping of the same gold-labeled PM sheets was performed. The peak value, Lmax, representing the extent of CTK spatial organization, is shown as a bar graph (n ≥ 15). Significant differences between control (SCR-expressing) and MTMR-silenced cells were assessed by one-way ANOVA tests for (B) and bootstrap tests for (C) (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001). SCR, scrambled shRNA.