Extended Data Fig. 1: Motion distinguishes translating from nontranslating secretome mRNAs.
From: Secretome translation shaped by lysosomes and lunapark-marked ER junctions
a, Golgi-like distribution of SiT-EGFP MS2 mRNA in U-2 OS cells. SiT-EGFP (green), MS2 (cyan), ER (orange). b, Mean squared displacement (MSD, µm2) vs lag time (τ, sec) for SiT-EGFP MS2 mRNAs under control (red) or puromycin (blue). Fitted curves: Dcontrol = 0.004 µm2/s, Dpuro = 0.033 µm2/s. c, MSD vs lag time of SiT-EGFP MS2 trajectories classified as translating (MSDτ=1sec < 0.055 µm2). d, Schematic of cytERM-SUNTAG MS2 construct (upper) and CrPV IRES cytERM-SUNTAG MS2 (lower). e, Boxplot of translating fractions of unmodified cytERM-SUNTAG MS2 in control (N = 20 cells), LNPK KD (N = 38), and CLIMP63 KD (N = 39). f, MSD vs lag time of SUNTAG(+) cytERM-SUNTAG MS2 mRNAs, fitted Dapp=0.007 µm2/s. g, Violin plots of log(MSDτ=1sec) for SUNTAG(+) cytERM-SUNTAG MS2 (n = 72), CD4-EGFP MS2 (n = 251), SiT-EGFP MS2 (n = 1616), Calreticulin-mEmerald MS2 (n = 250), ER5-mEmerald MS2 (n = 1155), ER3-mEmerald MS2 (n = 2475), β-actin-Halo MS2 (n = 100), SUNTAG-Sec61β MS2 (n = 314), TOMM20-Halo MS2 (n = 233), SiT+puromycin (n = 1608), and SUNTAG(–) cytERM-SUNTAG MS2 (n = 680). Red dotted line, MSD = 0.055 µm2. h, Time-lapse images of Actin-Halo MS2 mRNA (green) and ER (magenta). Scale bars, 1 µm.
