Panel A shows fluorescence microscopy images and enlarged insets displaying endogenous Hsp47, GalNT, and TANGO1 localization around distinct endoplasmic reticulum exit site regions. Panel B shows a scatter plot comparing Sec31 fluorescence intensities between endoplasmic reticulum exit sites associated or not associated with PC1 condensates. The vertical axis represents Sec31 intensity in arbitrary units, while the horizontal axis represents condensate association categories. Panel C shows enlarged fluorescence microscopy images illustrating Col1A1 condensates positioned near Sec31-positive puncta structures. Panel D shows fluorescence microscopy images and zoomed insets comparing endogenous TANGO1 and Sec31 localization after non-targeting and TANGO1 knockdown treatments. Panel E shows a scatter plot comparing intracellular Col1A1 integrated density between wild-type and TANGO1 knockdown conditions. The vertical axis represents Col1A1 integrated density in arbitrary units, while the horizontal axis represents treatment categories. Panel F shows a scatter plot quantifying PC1 condensate numbers per cell after wild-type and TANGO1 knockdown treatments. The vertical axis represents the number of PC1 condensates per cell, while the horizontal axis represents treatment conditions.
Functional division of labor among ERES. (A) Fluorescence images of activated LX-2 cells stained for endogenous Hsp47 (magenta), GalNT (yellow), and TANGO1 (green) (top), and zoomed insets (bottom) showing two distinct pools of ERES bounded by dashed white lines. Region 1 shows the ERES pool associated with the Golgi, and region 2 shows the ERES pool associated with Col1A1 condensates (scale bars: 10 µm; inset: 5 µm). (B) Plot comparing the fluorescence intensity of Sec31 puncta in ERES that are associated with PC1 condensates vs those that are not associated with PC1 condensates. A total of 144 ERES associated with condensates and 127 ERES not associated with condensates from two independent experiments were analyzed (****P < 0.0001). (C) Panel showing different Col1A1 condensates (green) and associated Sec31 puncta (magenta) used to generate the fluorescence intensity profiles in Fig. 4 B (scale bar: 1 µm). (D) Fluorescence images of activated LX-2 cells treated with either NT siRNAs or siRNAs targeting TANGO1 (TANGO1 KD) stained for antibodies against endogenous TANGO1 (green) and Sec31 (magenta) (top), and zoomed insets (bottom) showing reduced TANGO1 levels upon knockdown (scale bars: 10 µm; inset: 5 µm). (E) Plot comparing Col1A1 integrated density in cells treated with either NT siRNAs (WT) or siRNAs targeting TANGO1 (TANGO1 KD). 97 cells in WT and 88 cells in TANGO1 KD from two independent experiments were analyzed (****P < 0.0001). (F) Plot quantifying the number of PC1 condensates in cells treated with either NT siRNAs (WT) or siRNAs targeting TANGO1 (TANGO1 KD) (ns: not significant). NT, nontargeting.