Figure 5.
Panel A presents a schematic model illustrating capture of PC1 condensates at endoplasmic reticulum exit sites. Panel B illustrates progression of the PC1 condensate from the endoplasmic reticulum exit site toward the ER-Golgi intermediate compartment. An upward arrow indicates directional movement through the endoplasmic reticulum exit site to ER-Golgi intermediate compartment conduit, potentially driven by capillary action or extrusion forces. Panel C illustrates dissociation of PC1 from associated chaperones after entry into the ER-Golgi intermediate compartment. Col1A1-containing material advances through the secretory pathway, while TANGO1 remains retained at the endoplasmic reticulum exit site.
Model for the liquid-like mode of PC1 export. (A) ER luminal domain of TANGO1 captures PC1 condensates at ERES. (B) PC1 progresses from the ERES to the ERGIC due to capillary action or forced extrusion at the ER-ERES junction. (C) Changes in pH and/or calcium within the ERES-ERGIC conduit dissociate PC1 from chaperones. PC1 then moves forward along the secretory pathway, whereas TANGO1 is retained at the ERES. Elements in the figure have been generated using BioRender.